These technical standards provide criteria for the design and construction of onsite wastewater treatment and disposal technologies and components, in order to obtain an OWTS construction permit.
(Ord. 435 § 3, 2018)
Definitions established in Section 15.40.020 (Chapter 15.40) of the Malibu Municipal Code shall apply to this chapter.
(Ord. 435 § 3, 2018)
Any new or replacement OWTS shall comply with the following requirements. Repair of any lawfully existing OWTS, where no expansion or intensification of use is proposed, shall conform to these requirements to the greatest extent practicable as determined by the administrative authority.
A. 
Soil Depth. For conventional OWTS discharging septic tank effluent, minimum depth of soil beneath the bottom of the dispersal field shall be five feet for leaching trenches/beds and 10 feet for seepage pits. Where advanced treatment is provided, minimum soil depth for leaching trenches/beds may be reduced to three feet. Where advanced treatment and subsurface drip dispersal methods are used, minimum soil depth may be reduced to two feet below the drip line.
B. 
Vertical Separation to Groundwater. For new conventional OWTS discharging septic tank effluent, minimum vertical separation between the bottom of the dispersal system and seasonal high groundwater depth level shall be five feet for leaching trenches/beds and 10 feet for seepage pits. For advanced OWTS where supplemental treatment is provided, minimum groundwater separation for leaching trenches and beds may be reduced to three feet. For advanced OWTS where supplemental treatment and either pressure distribution or subsurface drip dispersal methods are used, minimum depth to groundwater may be reduced to two feet below the trench/bed or drip line, as applicable. Determination of compliance with the above groundwater separation requirements shall account for any projected water table rise as determined through groundwater mounding analysis, where applicable (see Section 15.40.090).
C. 
Soil Percolation. For conventional dispersal trenches/beds the soils shall have a demonstrated percolation rate in the range of five to 60 minutes per inch (mpi). Absorption rates for seepage pits must not be less than 0.83 gallons per square foot and must include supplemental treatment. Horizontal dispersal systems (trenches, beds, drip) in soils with percolation rates in the range of one to five mpi (fast percolation) must have supplemental treatment and pressure distribution. Soils with percolation rates of 60 to 120 mpi (slow percolation) are only permissible for effluent disposal with advanced OWTS that includes supplemental treatment and subsurface drip dispersal. The applicable percolation test method is described in the Malibu OWTS Manual.
D. 
Ground Slope. No soil absorption fields shall be located on slopes greater than 45%. Conventional gravity trench leachfields shall not be installed on slopes greater than 30%. Soil absorption fields located on slopes between 30 and 45% shall be designed to address critical factors of soil depth, restrictive horizons, soil permeability, application rates and dispersal methods. Siting of effluent dispersal systems on slopes greater than 10% shall be evaluated to assess possible impacts of lateral migration of effluent. The evaluation results, along with an evaluation of slope stability, shall be submitted for review and approval.
E. 
Horizontal Setbacks. Minimum horizontal setback distances from various site features to OWTS components shall be as listed in Table 15.42.030(E).
Table 15.42.030(E)
Minimum Horizontal Setback Distances for OWTS (feet)
Site Feature
Building Sewer
Septic Tank
Dispersal Trench or Bed
Seepage Pit
Buildings or structures1
2
5
8
8
Property line
Clear2
5
5
8
Water supply wells
 
 
 
 
Domestic
503
150
150
150
Public
503
150
1504
2004
Springs
-
50
100
100
Streams
 
 
 
 
General (from top of bank)
50
100
100
150
Between 1,200'—2,500' of a public water intake5
-
-
200
200
Within 1,200' of a public water system intake5
-
-
400
400
Reservoirs
 
 
 
 
General
50
100
200
200
Within 1,200' of a public water supply intake5
-
-
400
400
Ocean waters (from mean high tide line)6
-
50
100
100
Storm drainage pipe7
 
5
50
50
Cut bank or embankment
-
10
4 x h8
4 x h8
Unstable land mass9
 
100
100
100
Trees
-
10
-
10
Seepage pit
-
5
5
12
Dispersal trench or bed
-
5
4
5
Distribution box
-
-
5
5
Onsite domestic service line
110
5
5
5
Pressure public water main
1011
10
10
10
Notes:
1
Including porches and steps, whether covered or uncovered, breezeways, roofed porte cocheres, roofed patios, carports, covered walks, covered driveways, and similar structures and appurtenances.
2
See California Plumbing Code, Section 321.3.
3
Drainage piping shall clear domestic water supply wells by not less than 50 feet. This distance shall be permitted to be reduced to not less than 25 feet where the drainage piping is constructed of materials approved for use within a building.
4
200 feet for trench or seepage pit 10 feet deep; 2-yr microbial travel study required for seepage pit >20′ deep within 600 feet of public water well, per Statewide OWTS Policy Section 9.4.10.3.
5
For areas tributary to and upstream of water supply intake; setback distance measured from high water mark. Exceptions allowed per Statewide OWTS Policy, as follows: (a) for replacement OWTS, comply to the maximum extent practicable and incorporate supplemental treatment unless the administrative authority finds no impact or significant threat to water source; (b) for new OWTS on pre-existing lot of record (pre-May 13, 2013), comply to maximum extent practicable and incorporate supplemental treatment for pathogens per Sections 10.8 and 10.10 of Statewide OWTS Policy as detailed in the Malibu OWTS Manual.
6
Systems that provide supplemental (secondary or tertiary) effluent treatment prior to discharge to the subsurface effluent dispersal systems are not required to meet these minimum horizontal setback requirements provided that no parts of the OWTS are, at any time, submerged or exposed to direct contact with these surface water bodies. In the case of beachfront developments and redevelopments, the OWTS shall, to the maximum extent feasible, be located at the farthest point from the ocean on a parcel to avoid the construction of protective structures such as sea walls and shoreline protection devices.
7
Where publicly owned storm drainage pipes run across a property rendering it impossible to meet these minimum horizontal setback requirements, the effluent dispersal system is allowed to be located within 50 feet of the pipes provided that these pipes are positioned vertically higher than the bottom of the effluent dispersal system or the applicant demonstrates that the pipes are sealed so that there is no possibility for shallow groundwater to infiltrate the storm drain.
8
"h" equals the height of cut or embankment, in feet. Where a California certified engineering geologist and/or registered geotechnical engineer finds and states in writing that the stability of the fill or cut bank will not be compromised by a shorter horizontal separation and that a shorter horizontal separation will not result in sewage effluent daylighting, a shorter horizontal setback for the effluent dispersal system can be used per the said geologist's recommendation.
9
Setback distance may be reduced in accordance with recommendations provided in a geotechnical report prepared by a civil engineer or professional geologist and addressed in the OWTS design report and accompanying geotechnical report.
10
See California Plumbing Code, Section 720.0.
11
For parallel construction; for crossings, approval by the Health Department shall be required.
F. 
Flood Hazard Areas. Disposal systems shall be located outside of flood hazard areas.
Exception: Where suitable sites outside of flood hazard areas are not available, disposal systems shall be permitted to be located in flood hazard areas on sites where the effects of inundation under conditions of the design flood are minimized.
(Ord. 435 § 3, 2018)
For all locations where an OWTS is proposed to be installed, site evaluations per the OWTS Manual shall be conducted prior to issuance of an OWTS construction permit to verify conformance with applicable soils, groundwater, horizontal setbacks, ground slope and other requirements as prescribed in Chapters 15.40 and 15.42 of the Malibu Municipal Code. In addition, the following reports and tests shall be submitted.
A. 
OWTS Design Report. The permit application for a new or replacement OWTS installation shall include an OWTS design report prepared by a qualified professional. The report shall summarize and integrate the results of supporting geotechnical soils analyses and/or percolation tests, system design specifications and site limitations and special characteristics, as per the technical standards.
B. 
Supporting Geology Report. Site evaluation methods shall include soil profiles, borehole and test pit logs, slope stability report if applicable, and other exploratory tests, as necessary, to verify adequate depth and permeability of soil, soil thickness, and vertical separation between dispersal field and groundwater for both primary and reserve dispersal areas. Information in the report shall include, but not be limited to: soil conditions, characteristics and estimated permeability, depth of zones of saturation, depth to bedrock, surrounding geographic and topographic features, direction of ground contour and percent slopes, distance to drainages, water bodies and potential for flooding. Soils classification testing shall be conducted in accordance with the technical standards contained in this code and guidelines provided in the Malibu OWTS Manual and the results expressed in United States Department of Agriculture classification terminology including descriptions of both soil texture and soil structure. Soils classification for engineering properties shall be conducted by a California registered geotechnical engineer or a California registered civil engineer in the environmental/geo-technical field.
C. 
Percolation/Infiltration Testing. Percolation tests shall be conducted by a California registered geologist, a California registered geotechnical engineer, a California registered civil engineer, or a California registered environmental health specialist. Where the administrative authority has been provided adequate evidence to demonstrate suitable soil conditions and groundwater separation, testing requirements may be waived.
D. 
Land Division. For new divisions of land, soil profiles, percolation tests and groundwater determinations will be required on every parcel unless the administrative authority determines, on a case-by-case basis, that such testing is not necessary due to the availability of sufficient information to demonstrate conformance with applicable siting criteria for all proposed OWTS locations.
(Ord. 435 § 3, 2018)
A. 
General. Daily wastewater flow estimates shall be established by the registered OWTS designer for use in design, evaluation and monitoring of all OWTS. Flow rates are used for sizing treatment unit capacity and sizing of the dispersal system.
Single-Family Residences and Second Units. Wastewater flows used for design of OWTS treatment capacity for single-family residences and second units shall be based on the number of bedrooms in accordance with criteria in Table 15.42.030(B)-1. The flow is calculated as 300 gallons per day for the first bedroom (master) and 150 gallons per day for each additional bedroom. The design flows for a primary residence and secondary dwelling unit shall be determined independently, regardless of whether the flows are treated separately or combined in a single OWTS.
Table 15.42.050(B)-1
Wastewater Design Flows for OWTS Treatment Units Serving Single-Family Residences and Second Units
No. of Bedrooms
Design Flow (gal/day)
1 (Master bedroom)
300
2
450
3
600
4
750
5
900
6
1,050
>6
+ 150 per bedroom
B. 
Multiple Dwelling Units. Wastewater flows used for the design of OWTS for multiple residential units shall be based on the number of dwelling units in accordance with criteria in Table 15.42.030(B)-2. The flow is calculated as 300 gallons per day for the first bedroom (master) and 150 gallons per day for each additional bedroom.
Table 15.42.050(B)-2
Wastewater Design Flows for OWTS Treatment Units Serving Multiple Dwelling Units
No. of Dwelling Units
(1 bedroom each)*
Design Flow (gal/day)
2
600
3
900
4
1,200
5
1,500
6
1,800
7
2,100
8
2,400
9
2,700
10
3,000
>10
+300 per unit
Notes:
*
Extra bedrooms add 150 gallons each.
Commercial and Home Occupation Uses Described in Section 15.40.050(A)(1). Wastewater flows used for design of OWTS for uses other than residential shall be estimated based on the projected activities, occupancy, and facilities, using wastewater generation guidelines provided in Table 15.42.030(B)-3. For facilities not listed in Table 15.42.030(B)-3 the wastewater design flow shall be estimated based on either: (1) appropriate literature references (e.g., US EPA) for the type of facility proposed; or (2) documented wastewater flow monitoring data for no less than three comparable facilities. Additionally, the administrative authority may consider adjustment to the criteria listed in Table 15.42.030(B)-3 for specific facilities based upon documented wastewater flow monitoring data. In all cases, the design proposal shall include sufficient technical information to support the proposed design flow estimate. Notwithstanding the above, minimum design flow for any OWTS shall not be less than 150 gpd.
C. 
Table 15.42.050(B)-3
Estimated Sewage/Waste Flow Rates
Type of Occupancy
Design Flow (gal/day)
Airports
 
-Per employee
15
-Per passenger
5
Auto washers
Per equipment mfg.
Bowling alleys, snack bar only (per lane)
75
Camps (per person)
 
-With central comfort station
35
-With flush toilets, no showers
25
-Day camps, no meals served
15
-Summer and seasonal
50
Churches, sanctuary, religious halls (per seat)
 
-without kitchen
5
-with kitchen waste
7
Dance halls (per person)
5
Day care (per patron, employee)
15
Factories and industrial buildings (per employee)
 
-no showers
25
-with showers
35
-cafeteria, add
5
Hospitals
 
-per bed
250
-kitchen waste only (per bed)
35
-laundry waste only (per bed)
5
Hotels, no kitchen waste (per bed x 2)
60
Institutions (per person)
 
-resident
75
-nursing home
125
-rest home
125
Laundries, self-service
 
-minimum 10 hours per day (per wash cycle)
50
-commercial
Per manufacturer
Motel (per bed space)
 
-no kitchen
50
-with kitchen
60
Offices (per employee)
20
Parks
 
-mobile homes (per space)
250
-picnic parks, toilets only (per parking space)
20
-Recreational vehicles (per space)
 
• without water hook-up
75
• with water and sewer hook-up
100
Restaurants – cafeterias
 
-per seat
50*
-per employee
20
-toilet (per customer)
7
-kitchen waste (per meal
6
-add for cocktail lounge (per customer)
2
-kitchen waste – disposable service (per meal)
2
Schools
 
-staff and office (per person)
20
-elementary students (per student)
15
-intermediate and high (per student)
20
• with gym and showers
5
• with cafeteria, add
3
-boarding, total waste (per person)
100
Service station, toilets
3
-for 1st bay
1,000
-add for each additional bay
500
Stores
 
-per employee
20
-public restrooms, add per 10 ft2 of floor space
1
Swimming pools, public (per person)
10
Theaters
 
-auditoriums (per seat)
5
-drive-in (per space)
10
Notes:
*
Number of seats shall be determined based on 15 square feet per seat in service area.
D. 
Flow Equalization. Flow equalization is the process of controlling the rate of wastewater flow through an OWTS by providing surge capacity storage and timed-dosing of the incoming flow. It allows peak surges in wastewater flow (e.g., from a weekend event) to be temporarily stored and metered into the treatment system and/or dispersal field at a relatively even ("average") rate over an extended number of days (e.g., during the subsequent week). This process may be used for commercial and multifamily systems as recommended by the OWTS designer.
(Ord. 435 § 3, 2018; Ord. 517, 6/24/2024)
Special design measures will be required for high strength wastewater and other instances where it is determined by the administrative authority that the quantity and/or quality of wastewater poses unusual treatment or disposal challenges not addressed by conventional or advanced treatment methods. These systems shall be subject to review and approval by the administrative authority on a case-by-case basis. Examples include, but are not limited to:
A. 
Installations where appreciable amounts of industrial or indigestible wastes are produced;
B. 
Occupancies producing abnormal quantities of sewage or liquid waste;
C. 
Where grease interceptors are required by the California Plumbing Code; or
D. 
As required by the Regional Water Quality Control Board.
(Ord. 435 § 3, 2018)
A. 
General. New and replacement OWTS septic tanks shall be limited to those approved by the IAPMO or designed by a California registered civil engineer to meet structural design standards acceptable to the administrative authority, and their installation shall be according to the manufacturer's instructions.
B. 
Capacity. The liquid capacity of all septic tanks shall conform to Table 15.42.070 as determined by: (1) the number of bedrooms or dwelling units; and (2) the number of plumbing fixture units, whichever is greater. The minimum total capacity of a septic tank shall be at least 1,500 gallons.
Table 15.42.070
Septic Tank Capacity
Single-Family Dwellings/Second Dwelling Units # of Bedrooms
Multiple Dwelling Units (1 bedroom each)
Maximum Drainage Fixture Units
Minimum Septic Tank Capacity4 (gallons)
1 to 61
2 to 3 units
33
1,500
-
4
45
2,000
-
5
55
2,250
-
6
60
2,500
-
7
70
2,750
-
8
80
3,000
-
9
90
3,250
-
102
1003
3,500
Notes:
1
Additional bedrooms, 150 gallons each.
2
Additional dwelling units, 250 gallons each.
3
Additional fixture units over 100, 25 gallons per fixture unit.
4
Septic tank sizes in this table include sludge storage capacity and the connection of domestic food waste disposal units without further volume increase.
C. 
Plans. Plans for septic tanks shall be submitted to the administrative authority for approval. Such plans shall show dimensions, reinforcing, structural calculations, and such other pertinent data as required.
D. 
Design. Septic tank design shall be such as to produce a clarified effluent consistent with accepted standards and shall provide adequate space for sludge and scum accumulations.
E. 
Compartments. Septic tanks shall have not less than two compartments unless otherwise approved by the administrative authority. The inlet compartment of any septic tank shall be not less than two-thirds of the total capacity of the tank, nor less than 1,000 gallons liquid capacity. The secondary compartment of a septic tank shall have a capacity of not less than 500 gallons and a capacity not exceeding one-third of the total capacity of such tank.
F. 
Access Manholes. Access to each septic tank shall be provided by at least two manholes 24 inches (610 mm) in minimum diameter. One access manhole shall be located over the inlet and one access manhole shall be located over the outlet. Wherever a first compartment exceeds 12 feet (3,658 mm) in length, an additional manhole shall be provided over the baffle wall. Septic tanks shall have the required manholes accessible by extending the manhole openings to grade in a manner acceptable to the administrative authority.
G. 
Pipe Opening Sizes. The inlet and outlet pipe openings shall not be larger in size than the connecting sewer pipe. The vertical leg of round inlet and outlet fittings shall not be less in size than the connecting sewer pipe nor less than four inches (102 mm). A baffle-type fitting shall have the equivalent cross-sectional area of the connecting sewer pipe and not less than a four-inch (102 mm) horizontal dimension where measured at the inlet and outlet pipe inverts.
H. 
Pipe Extension. The inlet and outlet pipe or baffle shall extend four inches (102 mm) above and not less than 12 inches (305 mm) below the water surface. The invert of the inlet pipe shall be at a level not less than two inches (51 mm) above the invert of the outlet pipe.
I. 
Free Vent Area. Inlet and outlet pipe fittings or baffles and compartment partitions shall have a free vent area equal to the required cross-sectional area of the house sewer or private sewer discharging therein to provide free ventilation above the water surface from the disposal field or seepage pit through the septic tank, house sewer, and stack, or other approved vent, to the outer air.
J. 
Sidewalls. The sidewalls shall extend not less than nine inches (229 mm) above the liquid depth. The cover of the septic tank shall be not less than two inches (51 mm) above the back vent openings.
K. 
Partitions and Baffles. Partitions or baffles between compartments shall be of solid, durable material and shall extend not less than four inches (102 mm) above the liquid level. The transfer port between compartments shall be a minimum size equivalent to the tank inlet, but in no case less than four inches (102 mm) in size, shall be installed in the inlet compartment side of the baffle so that the entry into the port is placed 65% to 75% in the depth of the liquid. Wooden baffles are prohibited.
L. 
Effluent Filter. New and replacement OWTS septic tanks shall be designed to prevent solids in excess of three-sixteenths of an inch in diameter from passing to the dispersal system. Septic tanks that use a NSF/ANSI Standard 46 certified septic tank effluent filter at the final point of effluent discharge from the OWTS and prior to the dispersal system shall be deemed in compliance with this requirement.
M. 
Structural Design. Septic tanks shall be constructed of solid durable materials not subject to excessive corrosion or decay and shall be watertight. The structural design of septic tanks shall comply with the following requirements:
1. 
Each such tank shall be structurally designed to withstand all anticipated earth or other loads. Septic tank covers shall be capable of supporting an earth load of not less than 500 pounds per square foot (lb/ft2) (2441 kg/m2) where the maximum coverage does not exceed three feet (914 mm).
2. 
In flood hazard areas, and in areas where the groundwater elevation is above the tank bottom, tanks shall be anchored to counter buoyant forces. The vent termination and service manhole of the tank shall be not less than two feet (610 mm) above the design flood elevation or fitted with covers designed to prevent the inflow of floodwater or the outflow of the contents of the tanks during conditions of the design flood.
3. 
Traffic Rated Tanks. Septic tanks must be structurally designed to withstand all anticipated earth or other loads. Septic tanks located in traffic areas, including driveways, shall be designed to a minimum H-20 traffic ratings as established by the American Association of State Highway Transportation Officials.
N. 
Materials. The materials used for constructing a septic tank shall be in accordance with the following:
1. 
Materials used in constructing a concrete septic tank shall be in accordance with applicable standards in the California Plumbing Code, Table 1401.1.
2. 
Septic tanks constructed of alternate materials may be approved by the administrative authority where in accordance with approved applicable standards. Wooden septic tanks shall be prohibited.
O. 
Prefabricated Septic Tanks. Prefabricated septic tanks shall comply with the following requirements:
1. 
Manufactured or prefabricated septic tanks shall comply with approved applicable standards and be approved by the administrative authority.
2. 
Independent laboratory tests and engineering calculations certifying the tank capacity and structural stability shall be provided as required by the administrative authority.
P. 
Water-Tightness Testing Requirements. All new septic tank installations and modifications to existing septic tanks shall undergo water-tightness testing as follows:
1. 
New Tanks. For new tank installations, the testing shall be done with the access risers in place and the inlet and outlet pipes plugged. The tank shall be filled with water to a level extending a minimum of two inches into the risers, and monitored for a minimum one-hour period, with no measurable drop in the water level.
2. 
Existing Tanks. For existing tanks, the tank shall be filled with water to a level even with the invert of the outlet pipe, and monitored for a one-hour period, with no measurable drop in water level. However, in cases where there the groundwater level is known or estimated to rise above the level of the outlet pipe during any time of the year, the water-tightness test shall be conducted following the procedure for new tank installations; i.e., by filling the tank with water into the risers.
(Ord. 435 § 3, 2018)
A. 
Interceptor. Where liquid wastes contain excessive amounts of grease, garbage, flammable wastes, sand, or other ingredients that affect the operation of a OWTS, an interceptor for such wastes shall be installed as designed by the OWTS designer.
B. 
Installation. Installation of such interceptors shall comply with the applicable sections of the California Plumbing Code, and they shall comply with the siting requirements for septic tanks contained in this code. The administrative authority may require and approve additional more restrictive standards.
C. 
Sampling Box. A sampling box shall be installed when required by the administrative authority.
D. 
Design and Structural Requirement. Interceptors shall be of an approved design and include at least two compartments unless otherwise approved by the administrative authority for good cause. Structural requirements shall be in compliance with the applicable requirements for septic tanks, per Section 15.42.070 of this chapter.
E. 
Location. Interceptors shall be located as close to the source of waste as possible and be accessible for servicing. Manholes for servicing shall be at grade level and be gastight.
F. 
Waste Discharge. Waste discharge from interceptors may be connected to a septic tank or other OWTS component or be disposed into an approved separate disposal system.
G. 
Sizing and Design Criteria. Systems shall be designed based on wastewater flow rates from Table 15.42.050(B)-3 of this chapter and applicable sections of the California Plumbing Code.
(Ord. 435 § 3, 2018)
A. 
General.
1. 
Supplemental treatment to provide secondary (or better) effluent quality may be provided by: (a) site-specific application of sanitary engineering principles/methods (e.g., intermittent sand, aerobic bioreactors with clarifiers); and/or (b) proprietary treatment units.
2. 
Propriety treatment units cover a category of manufactured or "package" systems specifically developed for residential and other small-scale sewage treatment applications. Most proprietary designs currently available fall into the following categories: (a) aerobic treatment units (ATUs); (b) media filters; and (c) fixed-film activated sludge units.
3. 
Disinfection units are an example of a supplemental treatment component providing tertiary treatment, but only have applicability with secondary (or better) effluent quality produced by a supplemental treatment unit per subsection (A)(2) above.
4. 
Effluent from supplemental treatment units may be discharged to an approved type of dispersal system, including conventional and pressure distribution trenches or beds, chamber systems, subsurface drip dispersal fields, seepage pits, or combinations thereof.
5. 
Supplemental treatment may be required as part of an advanced protection management program in conformance with Statewide OWTS Policy Sections 10.9 and 10.10.
B. 
Design Requirements.
1. 
General. The OWTS designer and OWTS installer shall follow the proprietary manufacturer's design, installation, construction, and operations procedures, as applicable. All supplemental treatment systems shall be operated in compliance with applicable design requirements particular to the type of system, the facility served, and the site conditions in compliance with the manufacturer requirements.
2. 
Tanks and Components.
a. 
All tanks shall be structurally sound, watertight, operate in such a manner as to not create odors or vector attraction, be properly vented, and have a functional baffle(s).
b. 
All components of the system shall be functional, in good working order, and shall meet the design requirements for the specific site conditions and application for which they are approved.
c. 
Proprietary treatment units and components shall be structurally sound, free from defects, be watertight, and not create odor or vector attraction nuisance. The unit shall be operated in accordance with the approved manufacturer and certification/listing organization standards.
C. 
Sizing and Design Criteria.
1. 
Design Wastewater Flow. Sizing and design of supplemental treatment units shall be based on the projected wastewater flow for the building or facility being served, determined in accordance with wastewater flow requirements contained in this code.
2. 
Tanks. Sizing and design of tanks shall be in accordance with the structural and volumetric capacity requirements of this code. All tanks housing a proprietary treatment unit shall be structurally sound, watertight and capable of withstanding anticipated loads and buoyant forces, as applicable.
3. 
Controls. Control panels shall be designed and configured in such a manner that, in the event of a treatment unit malfunction, an alarm system will be triggered and discharge from the treatment system to the dispersal field will be interrupted until the treatment unit malfunction is rectified. At a minimum, the alarm system shall include an audible and visual alarm at building served by the system.
4. 
Emergency Storage Provisions. Where a supplemental treatment unit is used in conjunction with a non-gravity fed dispersal system, the system shall provide emergency storage capacity equal to at least the daily wastewater flow (in gallons) or provide an audible and visible alarm with a telemetry connection to the registered maintenance provider.
5. 
Compliance with Manufacturer Requirements. The design shall follow the proprietary manufacturer's design, installation, construction, and operations procedures, as applicable.
(Ord. 435 § 3, 2018)
A. 
General. The construction dimensions of the subsurface sewage effluent disposal area of an onsite wastewater treatment system shall be based on soils analysis and/or percolation tests. Soils analysis shall be conducted by a licensed soils engineer and the results expressed in United States Department of Agriculture classification terminology. Percolation tests shall be conducted by a California registered professional geologist, a California registered civil engineer, or a California registered environmental health specialist. Specific methodologies for these tests are provided in the Malibu OWTS Manual and design criteria listed below.
B. 
Sizing and Design Criteria.
1. 
Minimum Effective Absorption Area. The minimum effective absorption area required shall be sufficient for absorption of the daily quantity of liquid waste discharging into the dispersal system, determined by either: (a) the required septic tank capacity in gallons (liters); and/or (b) the estimated daily waste/sewage flow, whichever is greater.
2. 
Absorption Capacity. The absorption capacity of disposal trenches and beds shall be based on the effective absorption area and the percolation characteristics of the underlying and surrounding soil, as determined from results of field percolation testing and design criteria. Present and future dispersal areas must be tested.
3. 
Effective Absorption Area. The effective absorption area of a disposal trench shall normally be calculated as the bottom width. Sidewall area in excess of the required 12 inches (305 mm) and not exceeding 36 inches (914 mm) below the leach line shall be permitted to be added to the trench bottom area where computing absorption areas.
4. 
Leaching Beds. Where leaching beds are permitted in lieu of trenches, the area of each such bed shall be not less than 50% greater than the requirements for trenches. Perimeter sidewall area in excess of the required 12 inches (305 mm) and not exceeding 36 inches (914 mm) below the leach line shall be permitted to be added to the trench bottom area where computing absorption areas.
5. 
Leaching Chambers. Leaching chambers shall be sized on the bottom absorption area (nominal until width) in square feet with no reduction in sizing less than 30%.
C. 
Construction. Disposal fields shall be constructed in accordance with Table 15.42.100 Disposal fields shall not be installed in uncompacted fill.
Table 15.42.100
General Disposal Field Requirements
Item
Minimum
Maximum
Number of drain lines per field
1
-
Length of each line
-
100 feet
Bottom width of trench
18 inches
36 inches
Spacing of lines, center-to-center
6 feet
-
Depth of earth cover of lines
12 inches
-
Grade of lines
Level
3 inches per 100 feet
Filter material under drain lines
121 inches
-
Filter material over drain lines
2 inches
-
D. 
Distribution Lines. Distribution lines shall be constructed of perforated ABS pipe, perforated PVC pipe, or other materials approved by the administrative authority, provided that sufficient openings are available for distribution of the effluent into the trench area.
E. 
Grade Board. A grade board staked in the trench to the depth of filter material shall be utilized when the distribution line is constructed of material which will not maintain alignment without continuous support.
F. 
Distribution Boxes. Where two or more drain lines are installed, an approved distribution box of sufficient size to receive lateral lines shall be installed at the head of each disposal field. The inverts of outlets shall be level, and the invert of the inlet shall be not less than one inch (25.4 mm) above the outlets. Distribution boxes shall be designed to ensure equal flow and shall be installed on a level concrete slab in natural or compacted soil.
G. 
Laterals. Laterals from a distribution box to the disposal field shall be approved pipe with watertight joints. Multiple disposal field laterals, where practicable, shall be of uniform length.
H. 
Connections. Connections between a septic tank and a distribution box shall be laid with approved pipe with watertight joints on natural ground or compacted fill.
I. 
Spacing.
1. 
Minimum spacing between trenches or leaching beds shall be not less than four feet (1,219 mm) plus two feet (610 mm) for each additional foot (305 mm) of depth in excess of one foot (305 mm) below the bottom of the drain line.
2. 
Distribution drain lines in leaching beds shall be not more than six feet (1,829 mm) apart on centers, and no part of the perimeter of the leaching bed shall exceed three feet (914 mm) from a distribution drain line.
3. 
When seepage pits are used in combination with disposal fields, the filter material in the trenches shall terminate at least five feet (1,524 mm) from the seepage pit excavation.
J. 
Surface Covering. Disposal fields, trenches, and leaching beds shall not be paved over or covered by concrete or a material that is capable of reducing or inhibiting a possible evaporation of sewer effluent. Exceptions may be approved by the administrative authority for site with sand soil type and alternate ventilation design.
K. 
Joints. Where necessary on sloping ground to prevent excessive line slope, leach lines or leach beds shall be stepped. The lines between each horizontal section shall be made with watertight joints and shall be designed so each horizontal leaching trench or bed shall be utilized to the maximum capacity before the effluent shall pass to the next lower leach line or bed. The lines between each horizontal leaching section shall be made with approved water-tight joints and installed on natural or unfilled ground.
L. 
Dosing Tanks. Where approved by the administrative authority, dosing tanks used in conjunction with an OWTS may be used. Automatic siphon or dosing tanks shall be installed when required or as permitted by the administrative authority.
(Ord. 435 § 3, 2018)
A. 
General. The construction dimensions of the subsurface sewage effluent disposal area of an onsite wastewater treatment system utilizing seepage pits shall be based on soils analysis and percolation tests. Soils analysis shall be conducted by a licensed soils engineer and the results expressed in United States Department of Agriculture classification terminology. Percolation tests shall be conducted by a licensed geologist, a licensed soils engineer, a licensed civil engineer, or a California registered environmental health specialist. Specific methodologies for these tests are provided in the Malibu OWTS Manual and design criteria listed below.
B. 
Sizing and Design Criteria.
1. 
Effective Absorption Area. The effective absorption area of any seepage pit shall be calculated as the excavation sidewall area in square feet (ft2) below the inlet, excluding impermeable soil zones where identified during field exploration.
2. 
Absorption Capacity. The absorption capacity of seepage pits shall be based on the effective absorption area per effective absorption area requirements and the percolation characteristics of the surrounding soil, as determined from results of field percolation testing and design criteria. Present and future dispersal areas must be tested.
3. 
Minimum Effective Absorption Area. The minimum effective absorption area required shall be sufficient for absorption of the daily quantity of liquid waste discharging into the dispersal system, based on either: (a) the required septic tank capacity in gallons (liters); and/or (b) the estimated daily waste/sewage flow, whichever is greater.
4. 
Multiple Pits and Disposal Combinations. The minimum required absorption area may be provided in one or more seepage pits or in combination with other dispersal methods, e.g., trenches, beds or subsurface drip dispersal.
C. 
Multiple Installations. Multiple seepage pit installations shall be served through an approved distribution box. Distribution boxes shall have their locations permanently marked with a steel post, concrete marker or other durable material. Additionally, each distribution box shall have an inspection riser of white PVC or concrete of at least eight inches in diameter. The inspection riser shall allow inspection access to the distribution box. Each riser shall terminate with an approved screw type cap.
D. 
Construction. Each seepage pit shall be circular in shape and shall have an excavated diameter of not less than four feet (1,219 mm). Approval shall be obtained prior to construction for any pit having an excavated diameter greater than six feet (1,829 mm). Seepage pits shall not be installed in uncompacted fill.
E. 
Spacing.
1. 
Minimum horizontal spacing between seepage pits shall be 12 feet, measured from sidewall to sidewall.
2. 
When seepage pits are used in combination with disposal fields, the filter material in the trenches shall terminate at least five feet (1,524 mm) from the seepage pit excavation.
F. 
Lining. Seepage pits may be constructed in one of two ways, as follows:
1. 
An eight-inch (204 mm) white, or other similar approved color, sewer pipe of approved material shall be installed true and plumb in the center of the seepage pit excavation extending from the bottom of the seepage pit excavation to the inlet depth. The sewer pipe shall have one-inch (25.5 mm) holes drill each 120 degrees of the sewer pipe circumference at 12 inch (306 mm) intervals on center minimum for the entire length of the sewer pipe to the inlet depth. The sewer pipe shall then extend watertight to grade and shall be capped with an approved screw type, accessible cap. The void between the sewer pipe and the seepage pit excavation shall then be filled with clean stone, gravel, or similar filter material acceptable to the administrative authority, varying in size from three-fourths inch to two and one-half inches (19.1 mm to 64 mm).
2. 
Pre-cast concrete circular sections approved by the administrative authority may be used. The void between the pre-cast circular sections and the seepage pit excavation shall have a minimum of six inches (152 mm) of clean three-fourths inch (19.1 mm) gravel or rock filter material. An approved type one- or two-piece reinforced concrete slab cover shall be installed on top of the pre-cast concrete circular sections. Each such cover shall have 2,500 pounds per square inch (17,238 kPa) minimum compressive strength shall be not less than five inches (127 mm) thick and shall be designed to support an earth load of not less than 400 pounds per square foot (19.2 kPa). Each such cover shall be provided with an eight-inch (204 mm) minimum inspection hole and shall be coated on the underside with an approved bituminous or other nonpermeable protective compound. An eight-inch (204 mm) white, or similar approved color, sewer pipe of approved material shall be installed true and plumb extending watertight from the cover inspection hole to grade and shall be capped with an approved accessible cap.
G. 
Sidewall. A seepage pit shall have a minimum side-wall of 10 feet (3,048 mm) below the inlet.
H. 
Cover. The cover/cap of a seepage pit shall be constructed and located as follows:
1. 
Approved-type one- or two-piece reinforced concrete slabs of not less than 2,500 lb/in2 (1,757,674 kg/m2) minimum compressive strength, not less than five inches (127 mm) thick, and designed to support an earth load of not less than 400 pounds per square foot (lb/ft2) (1,953 kg/m2). Each such cover shall be provided with a nine-inch (229 mm) minimum inspection hole with plug or cover and shall be coated on the underside with an approved bituminous or other nonpermeable protective compound.
2. 
Cap depth of the seepage pit (distance from the surface of the ground to the top of the effective portion of the seepage pit) shall be specified by the engineering geologist and incorporated as part of the OWTS design.
I. 
Inlet Fitting. An approved vented inlet fitting shall be provided in the seepage pit so arranged as to prevent the inflow from damaging the sidewall.
Exception: Where using a one- or two-piece concrete slab cover inlet, the fitting shall be permitted to be a one-fourth bend fitting discharging through an opening in the top of the slab cover. On multiple seepage pit installations, the outlet fittings shall comply with subsection (H)(1) of this section.
(Ord. 435 § 3, 2018)
A. 
General. Pressure distribution systems are a variation of a conventional disposal field system that use a pump and small-diameter pressure piping to achieve broad, uniform distribution of wastewater throughout the dispersal field for improved soil absorption and better treatment of percolating effluent. Pressure distribution can be used in conjunction with rock-filled trenches or leaching chamber dispersal fields, receiving either septic tank effluent or secondary/tertiary effluent from a supplemental treatment unit. Pressure distribution is not used with seepage pits. Specific methodologies for siting and design of these systems are provided in the Malibu OWTS Manual and the design criteria listed below.
B. 
Applications. Pressure distribution may be incorporated in any leaching trench/bed disposal field, and is required for the following situations:
1. 
Areas with ground slopes between 30 to 45%, in conjunction with supplemental treatment;
2. 
Areas with percolation rates of less than five mpi or greater than 60 mpi, in conjunction with supplemental treatment;
3. 
Beachfront properties;
4. 
To allow reduction of minimum vertical separation to groundwater (below trench bottom) from five feet to three feet or two feet for beachfront properties, in conjunction with supplemental treatment;
5. 
For large flow systems, e.g., with dispersal field lengths exceeding 500 lineal feet;
6. 
Disposal fields with non-uniform lateral lengths or irregular (non-rectangular) shapes; and
7. 
Situations as may be determined necessary due to site-specific soil, geology or other conditions.
C. 
Siting Criteria.
1. 
Setbacks. Horizontal setback requirements for pressure distribution trench systems shall be those applicable to conventional dispersal fields.
2. 
Vertical Separation Requirements.
a. 
Depth to Groundwater. Minimum depth to seasonal high groundwater for pressure distribution trench systems, as measured from trench bottom, shall be three feet.
b. 
Soil Depth. Minimum depth of soil, as measured from trench bottom to impermeable soil or rock, for pressure distribution trench systems shall be three feet.
3. 
Percolation Rate. Average percolation rate for pressure distribution trench systems shall be within the range of one mpi to 120 mpi, as determined in accordance with standard percolation requirements for conventional dispersal trenches.
4. 
Ground Slope. Maximum ground slope in areas used for pressure distribution systems shall be 45%. An evaluation of the disposal area shall be included in a slope stability report.
D. 
Sizing and Design Criteria.
1. 
Wastewater Treatment. Pressure distribution trench systems may be used for dispersal effluent that has received supplemental treatment (secondary or better), using an approved advanced treatment system.
2. 
Sizing. Pressure distribution trench systems shall be sized by percolation rates in the same manner as conventional dispersal trenches, according to requirements in this code and the Malibu OWTS Manual.
3. 
Pressure Dosing. Septic tank effluent shall be applied to the pressure distribution trench system by pressure dosing, utilizing a pump system or automatic dosing siphon. The pressure distribution system shall be designed in accordance with accepted engineering practices to achieve, at a minimum:
a. 
Uniform dosing of wastewater effluent throughout the system of pressure distribution trenches;
b. 
Adequate flow rate, screening of effluent and suitable piping network to preclude solids accumulation in the pipes or clogging of discharge orifices;
c. 
Suitable access provisions for inspection, testing and adjustment of the pressure distribution system; and
d. 
Dosing volume to achieve minimum of three to five doses per day at design flow conditions.
4. 
Pump System or Dosing Siphon. The pump system or dosing siphon, as applicable, shall be: (a) appropriate for sewage applications; (b) of the size and type to meet hydraulic design requirements consistent with engineering practice; and (c) designed and constructed in accordance with pump system/dosing siphon requirements provided in the Malibu OWTS Manual.
E. 
Construction and Materials.
1. 
Dispersal Trenches. Pressure distribution trenches shall conform to the same design and construction requirements as conventional trench requirements contained in this code, with the exception that the piping system shall consist of pressure piping rather than gravity piping and non-uniform lateral lengths and nonuniform disposal field dimensions shall be permitted.
2. 
Pressure Distribution Piping.
a. 
Pressure-Rated Pipe Material. All pipe, fittings and valves shall be pressure-rated PVC pipe, minimum 150 psi.
b. 
Solvent Welded. All joints in the pressure piping system shall be solvent welded.
c. 
Pipe Sizing. All pressure distribution pipes and fittings, including transport lines, manifolds, laterals and valves, must be adequately sized for the design flow, and shall be designed to minimize frictional losses to the maximum extent practicable.
d. 
Thrust Blocks. Concrete thrust blocks, or equivalent restraint, shall be provided at sharp changes in piping directions.
e. 
Shut-Off Valves. The distribution lateral for each trench shall be fitted with a shut-off valve to adjust or terminate the flow to individual trenches. This valve may be either a ball or gate valve, and shall be located in a utility/valve box.
f. 
Lateral End Riser. The end of each lateral shall be fitted with a 90 degree long sweep to facilitate line cleaning and hydraulic testing. The end riser pipe shall also be fitted with a ball valve and/or threaded end cap or plug, housed in a valve box.
(Ord. 435 § 3, 2018)
A. 
General. Subsurface drip dispersal is a method for disposal of treated wastewater that uses special drip tubing designed for use with wastewater. The dripline is placed nine to 12 inches below ground surface and makes use of the most biologically active soil zone for distribution, nutrient uptake and evapotranspiration of the wastewater. A drip dispersal system is comprised of small-diameter (one-half-inch to one-inch) laterals ("driplines"), spaced 24 inches apart, with small-diameter emitters (one-eighth-inch) located at 12 to 24 inches on-center along the dripline. Effluent is conveyed under pressure to the laterals, with timed doses. Prior to dispersal the effluent requires supplemental treatment.
B. 
Applications. Subsurface drip dispersal may be incorporated into the OWTS design for the following situations:
1. 
Areas with ground slopes between 30 to 45%;
2. 
Areas with percolation rates of less than five mpi or greater than 60 mpi;
3. 
To allow reduction of minimum vertical separation to groundwater (below trench bottom) from five feet to three feet;
4. 
To allow reduction of horizontal setbacks as approved by the administrative authority; and
5. 
Situations as may be determined necessary due to site-specific soil, geology or other conditions with approval from the administrative authority.
C. 
Siting Criteria.
1. 
Setbacks. Horizontal setback requirements for drip dispersal systems shall be those applicable to conventional dispersal fields, as specified in this code or as otherwise approved by the administrative authority.
2. 
Vertical Separation Requirements.
a. 
Depth to Groundwater. Minimum depth to seasonal high groundwater for drip dispersal systems, as measured from the dripline, shall be two feet.
b. 
Soil Depth. Minimum depth of soil, as measured from bottom of dripline to impermeable soil or rock, for drip dispersal systems shall be five feet, unless otherwise approved by the administrative authority.
3. 
Ground Slope. Maximum ground slope in areas used for drip dispersal systems shall be 45%. An evaluation of the disposal area shall be included in a slope stability report.
D. 
Sizing and Design Criteria.
1. 
Wastewater Treatment.
a. 
Wastewater effluent discharged to any drip dispersal system shall be treated with an approved supplemental treatment system, in accordance with applicable sections of this code.
b. 
All drip dispersal systems shall include a filtering device capable of filtering particles larger than 100 microns; this device shall be located downstream of the supplemental treatment system.
c. 
Additional requirements may be assigned in connection with criteria for use in advanced protection management areas.
2. 
Dripfield Sizing.
a. 
Wastewater Design Flow. Drip dispersal systems shall be designed to accept the design wastewater flow for the building or facility being served, determined in accordance with wastewater flow requirements contained in Section 15.42.050.
b. 
Wastewater Application Rates. Wastewater application rates used for sizing drip dispersal fields shall be based on either: (i) soil percolation rate determined in accordance with methods described in the Malibu OWTS Manual; or (ii) soil classification with hydraulic loading rates found in the 2002 USEPA Manual as depicted in Table 15.42.100. In applying these criteria, the wastewater application area refers to the ground surface area encompassed by the drip dispersal field.
c. 
Dripfield Area. Minimum sizing of the dripfield area shall be equal to the design wastewater flow divided by the applicable wastewater application rate from subsection (D)(2)(b) of this section.
d. 
Drip Emitter Coverage. For sizing purposes, effective ground surface area used for drip field sizing calculations shall be limited to no more than four square feet per drip emitter. For 200 lineal feet of dripline with emitters at two-foot spacing would provide a total of 100 emitters (200/2) and could be used for dispersal to an effective area of up to 400 ft2 (100 emitters x 4 ft2/emitter). Conversely, if wastewater flow and percolation/soils design information indicate the need for an effective area of 1,000 ft2, the dripline design and layout would have to be configured to provide a minimum of 250 emitters spaced over the required 1,000 ft2 of dispersal area.
e. 
Dripfield Zones. Dripfields may be divided into multiple zones which may be located in different areas of a site, as desired or needed to provide the required dripfield size. A single continuous dripfield area is not required. However, any areas proposed for drip dispersal shall be supported by field observations and measurements to verify conformance with soil suitability and other site requirements. Differences in soil conditions and percolation characteristics from one zone to another may require the use of correspondingly different wastewater application rates and dripfield sizing for each zone.
Table 15.42.130
Wastewater Application Rates for Subsurface Drip Dispersal Fields
(Adapted from 2002 USEPA Manual Table 4.3)
Soil Texture
Structure
Application Rate
(gpd/sf)
Gravelly coarse sand & coarser
Loose or cemented
0.0
Clay, sandy or silty clay silt loam
Weak or massive
0.0
Massive
0.0
Sandy clay loam, clay loam or silty clay loam
Massive
0.0
Sandy clay, clay or silty clay
Moderate to strong
0.2
Sandy clay loam, clay loam or silty clay loam
Weak
0.2
Sandy clay loam, clay loam or silty clay loam
Moderate to strong
0.4
Sandy loam, loam or silt loam
Weak
0.4
Sandy loam, loam or silt loam
Moderate to strong
0.6
Fine, very fine, loamy fine and very loamy fine sand
Not Applicable
0.8
Coarse, single grain sand
Not Applicable
1.2
3. 
Pressure Dosing. Secondary-treated effluent shall be delivered to the dripfield by pressure, employing a pump system and timed dosing. The pressure distribution system shall be designed in accordance with accepted engineering practices and manufacturer recommendations for drip dispersal systems to achieve, at a minimum:
a. 
Uniform dosing of treated effluent;
b. 
An adequate dosing volume and pressure per manufacturer's guidelines;
c. 
Adequate flow rate, final filtering of effluent and suitable piping network to preclude solids accumulation in the pipes and driplines or clogging of discharge emitters;
d. 
A means of automatically flushing the filter and driplines at regular intervals; and
e. 
Suitable access provisions for inspection, testing and adjustment of the dripfield and components.
f. 
As applicable, additional requirements for design and construction of pressure distribution piping systems specified for "pressure distribution systems" in this code shall also apply.
E. 
Construction and Materials.
1. 
Dripline Material. Dripline shall be manufactured and intended for use with secondary quality wastewater, with minimum 45 mil tubing wall thickness, bacterial growth inhibitor(s), and means of protection against root intrusion.
2. 
Dripfield Layout. The bottom of each dripline row shall be level and parallel to the slope contour.
3. 
Dripline Depth. The dripline depth shall be installed at a minimum depth of 12 inches below grade and must be continuously covered by a minimum depth of 12 inches of soil/mulch. Deeper placement of driplines may be considered on a case-by-case basis.
4. 
Length of Individual Driplines. The maximum dripline length shall be designed in accordance with accepted engineering practices and in accordance with the manufacturer's criteria and recommendations.
5. 
Line and Emitter Spacing. Line and emitter spacing shall be designed as appropriate for soil conditions, slope, and contour. There shall be a minimum spacing of 12 inches between emitters and no emitter shall be located less than 12 inches from the supply and return manifolds.
(Ord. 435 § 3, 2018)
A. 
General. All proposed OWTS on beachfront properties shall be designed and installed in accordance with this code and city coastal engineering requirements and shoreline protection requirements. Beachfront development that includes new OWTS or expansion of existing OWTS shall include secondary treatment with disinfection of effluent prior to discharging to any subsurface disposal system. Seepage pits shall not be allowed unless otherwise approved by the administrative authority for good cause.
B. 
Siting Criteria.
1. 
Setbacks. Horizontal setback requirements for beachfront OWTS shall be the same as those applicable to conventional dispersal fields as specified in this code and criteria contained in the Malibu OWTS Manual, or as otherwise approved by the administrative authority for good cause.
2. 
Vertical Separation Requirements.
a. 
Depth to Tidal Water and soil. The bottom of any leach trench or drainfield shall have a minimum of two feet temporary (seasonal) clearance and four feet (annual average) permanent clearance above the mean high tide elevation, saturated zone or impervious soil or rock as applicable.
b. 
Depth to Groundwater. Minimum depth to seasonal high groundwater, as measured from trench bottom, shall be five feet or as otherwise approved by the administrative authority for good cause.
C. 
Sizing and Design Criteria. The dispersal system shall be sized and designed in the same manner as pressure distribution systems, according to requirements in this code and the Malibu OWTS Manual. Effluent dispersal/disposal capacity shall be based on sand category design, for hydraulic loading.
1. 
Wastewater Treatment. Beachfront development that includes new OWTS or expansion of existing OWTS shall include secondary treatment with disinfection of effluent.
2. 
Shoreline Protection Devices. For new OWTS or expansion of existing OWTS, all system components shall be protected from tidal and wave uprush action by a shoreline protection device adequately designed and engineered by a state of California licensed civil engineer specializing in coastal engineering. Existing shoreline protection devices must provide protection greater than or equal to current coastal engineering standards or shall be modified to meet this code. The minimum horizontal distance between and portion of the OWTS and shoreline protection device, including returns shall not be less than five feet, or as otherwise approved by the administrative authority for good cause.
3. 
Vertical Clearance. The space above the OWTS shall have a minimum of six feet vertical clearance to the bottom of any structural element including any cover such as stucco or wood siding. The required clearance shall be maintained overall system components and shall extend horizontally to the open ocean side of the building with no obstructions other than shoreline protection devices.
4. 
Access. No portion of the OWTS shall be located under any portion of any structure whether covered or uncovered except as approved in conformance with criteria contained in the OWTS Manual or by the administrative authority for good cause. OWTS shall have adequate access and clearances for the purposes of system maintenance and repair without the removal of any permanent structures, landscaping or other similar obstructions to access the system.
(Ord. 435 § 3, 2018)
A. 
General. Construction and inspection of OWTS shall comply with the following:
1. 
Applicable provisions of the Malibu Municipal Code related to inspections for construction permits shall be required. Approved OWTS plans shall be required to be available for review at the construction site during inspections.
2. 
System components shall be labeled to identify the manufacturer. Septic tanks or other components of the OWTS shall have the rated capacity permanently marked on the unit.
3. 
Septic tanks and other components of the OWTS shall be installed as required by the administrative authority and manufacturer requirements.
4. 
The dispersal system shall be installed at the same location and depth as shown on approved plans.
5. 
Construction inspections by the project engineering geologist and OWTS designer shall be conducted as required by the qualified professional, as defined in Malibu Municipal Code Chapter 5.38, or administrative authority.
6. 
Flow Test. As part of the inspection a flow test shall be performed through the system to the point of effluent disposal. All lines and components shall be watertight as applicable. Capacities, required air space, fittings and performance requirements shall comply with the provisions set forth in these standards.
B. 
Leach Trenches/Beds. Filter Material. Before placing filter material or drain lines in a prepared excavation, all smeared or compacted surfaces shall be removed by raking to a depth of one inch (25.4 mm) and the loose material removed. Clean stone, gravel, slag, or similar material acceptable to the administrative authority, varying in size from three fourths inch to two and one-half inches (19.1 mm to 64 mm) shall be placed in the trench to the depth and grade required by this section. Drain pipe shall be placed on the filter material in an approved manner. The drain lines shall then be covered with filter material to the minimum depth required by this section and covered with material approved by the administrative authority to prevent closure of voids with earth backfill. No earth backfill shall be placed over the filter material until after inspection and acceptance.
Exception: Plastic leaching chambers approved by the administrative authority may be used in lieu of pipe and filter material. Chamber installations shall follow the rules for disposal fields, where applicable, and shall conform to manufacturer's installation instructions.
C. 
Seepage Pits.
1. 
Seepage pits shall be located in accordance with the approved plot plan or as otherwise approved by the administrative authority for good cause.
2. 
All seepage pits shall be fed through effluent laterals which are connected to a distribution box. No seepage pits shall be installed in series.
3. 
Filter material, when used, is to be two- to two-and-one-half-inch washed gravel. The filter material should not contain fine materials. The installer must demonstrate the gravel is washed by submittal of documentation from supplier or other approved means. Failure to comply may result in rejection of the seepage pit installed.
4. 
The effluent line installed within the seepage pit shall be a minimum eight-inch white (or similar approved color) PVC Schedule 40 or SDR 35 piping installed true and plumb. The effluent line shall have holes drilled each 120 degrees of the pipe circumference at 12 inches on center minimum for the entire length of the seepage pit below the inlet. The riser will extend flush with the surrounding ground or above and shall not be diminished in size. The riser shall be capped with an approved cap and must remain accessible at all times.
5. 
Lined seepage pits shall be allowed when approved by the administrative authority and comply with Section H 701.0 of the California Plumbing Code.
D. 
Pressure Distribution Trench Systems. At a minimum, inspection of the pressure distribution trench system installation shall include the items listed below. This is in addition to inspection work required for a supplemental treatment system, if used. Joint inspection by the OWTS designer, contractor, and administrative authority may be required.
1. 
Pre-construction inspection where the construction staking or marking of the supply and return piping, pump system and appurtenances is provided and construction procedures discussed;
2. 
Water tightness of septic tank and dosing (pump) tank;
3. 
Pipe or drip field layout, piping materials and installation, and all associated valves and connections;
4. 
Hydraulic testing of the pressure pipe system;
5. 
Functioning and setting of all control devices; and
6. 
Final inspection to verify that all construction elements are in conformance with the approved plans and specifications, and operation and maintenance guidelines/manual are provided to owner.
E. 
Drip Dispersal Systems. At a minimum, inspection of the drip dispersal system installation should include the items listed below. This is in addition to inspection work required for a supplemental treatment system, if used. Joint inspection by the OWTS designer, contractor, and administrative authority may be required.
1. 
Pre-construction inspection where the construction staking or marking of the drip lines, supply and return piping, pump system and appurtenances is provided and construction procedures discussed;
2. 
Water tightness of septic tank and dosing (pump) tank;
3. 
Drip field layout, piping materials and installation, and all associated valves and connections;
4. 
Hydraulic testing of the drip system;
5. 
Functioning and setting of all control devices; and
6. 
Final inspection to verify that all construction elements are in conformance with the approved plans and specifications, erosion control has been completed; and operation and maintenance guidelines/manual are provided to owner and administrative authority.
F. 
Tanks. Septic tanks and other OWTS vessels shall be filled with water to flow line and piping as applicable prior to requesting inspection. Seams or joints shall be left exposed (except the bottom), and the tank shall remain water-tight.
G. 
Supplemental Treatment Units. The following minimum inspections prior to commencing construction or covering any elements of the system shall be required. Joint inspection by the OWTS designer, OWTS installer, and administrative authority may be required.
1. 
Pre-construction inspection where the construction staking or marking of the treatment unit is to be placed and installation procedures are discussed;
2. 
Testing of the treatment unit:
a. 
Function and setting of all control devices and alarms,
b. 
Water-tightness of septic tank, treatment tank(s), and dosing tank, as applicable;
3. 
At final inspection completion and acceptance form signed/stamped by the OWTS designer, OWTS installer, OWTS operation and maintenance provider attesting that the treatment unit has been installed and is operating in conformance with design specifications shall be provided.
(Ord. 435 § 3, 2018)