This chapter shall apply to all territory embraced within the unincorporated area of the County of Santa Cruz, State of California.
(Ord. 4220 § 2, 1992; Ord. 5412 § 1, 2022)
TABLE 7.38.045 Minimum Lot Size for Existing Lots of Record | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Less than 6,000 sq. ft. | 6,000 sq. ft. | 15,000 sq. ft. | 0.5 acres | 1 acre | 2.5 acres | ||||
1. | Lots in existence prior to 12/17/70 and not under any of the conditions of item 4 of this table | Lots with public water supply | X1 | X | |||||
Lots with private water supply | X2 | ||||||||
2. | Lots created after 12/17/70 and before 10/31/78 and not under any of the conditions of item 4 of this table | Lots with public water supply | X | ||||||
Lots with private water supply | X | ||||||||
3. | Lots created after 10/31/78 and not under any of the conditions of item 4 of this table | All lots | X | ||||||
4. | Regardless of the date of recordation, the following are minimum lot size requirements for the areas listed below: | ||||||||
a. | Kristen Park Subdivision (Assessor's Book Page 62-17), and water quality constraint areas | All lots | X3, 4 | ||||||
b. | Water supply watershed in the San Lorenzo River Watershed and in the Coastal Zone, North Coast Planning Areas or Bonny Doon Planning Areas (excluding Kristen Park and water quality constraint areas) | All lots | X5 | ||||||
c. | Rio Del Mar Lodge Sites Nos. 1 and 2; Monte Toyon Subdivision No. 1; Assessor's Book Page 40-14, blocks 1 and 2 | Lots with public water supply | X | ||||||
Lots with private water supply | X | ||||||||
NOTE: Property owners should be aware that other land use constraints may prevent the development of parcels, especially parcels of 6,000 square feet or less. |
NOTES FOR TABLE 7.38.045 | |
|---|---|
(1) Lots of less than 6,000 square feet may be used for OWTS only if the lot has not, at any time since December 17, 1970, been held by the same owner of any contiguous undeveloped property which could have been combined with the lot to increase its area to at least 6,000 square feet. | |
(2) Lots of less than one acre but more than 15,000 square feet may use both an OWTS and on-site water supply if the applicant demonstrates that a public water supply cannot be obtained and that contiguous land cannot be acquired to enlarge the lot to at least one acre. | |
(3) For lots of less than two and one-half acres in the Kristen Park Subdivision, the applicant for an on-site sewage disposal permit must submit documentary evidence they have encumbered from future development, and prohibited and restricted, as evidenced by a document on file with the Recorder, all rights to construct any improvements which would be located upon at least one other separate lot of record, whether contiguous or noncontiguous, within the Kristen Park Subdivision. | |
(4) Exceptions to the two and one-half acre minimum lot size for parcels within water quality control areas other than the Kristen Park area may be made where one of the following conditions is met: | |
(i) The lot is combined with a contiguous undeveloped property to form one parcel of at least two and one-half acres; or | |
(ii) The applicant submits documentary evidence that they have legally encumbered from future development, and prohibited and restricted, as evidenced by a document on file with the Recorder, all rights to construct any improvements which would be located on an existing contiguous or noncontiguous parcel, or part of a parcel, located within the same watershed so that the total acreage of the parcel intended for development, and the parcel or part of parcel which shall be legally encumbered from development, shall equal or exceed two and one-half acres. | |
(5) Within water supply watersheds, existing parcels of record less than one acre in size may be approved for development utilizing an OWTS for commercial use if the parcel meets all of the following criteria: | |
(i) The parcel has a designation of Community Commercial, Neighborhood Commercial, Office, or Service Commercial, in the General Plan that was adopted on May 24, 1994; | |
(ii) It is to be developed for commercial use; | |
(iii) It is within the rural services line; | |
From Septic Tank To: | Minimum Permitted Distance in Feet |
|---|---|
Dispersal system | 5 |
Property line | 5 |
Foundation, structure, bearing weight building overhang, stormwater tight line | 5 |
Private individual water line | 10 |
Water main | 25 |
Stream, well, spring, watercourse, nonpublic water wells, monitoring wells1 | 100 |
Public water well, if dispersal 10 ft or less deep | 150 |
Public water well, if dispersal is greater than 10 ft deep | 200 |
Vernal pools, wetlands, lakes, ponds, ocean, or other surface water bodies | 200 |
Seasonal drainageway that carries water more than 12 hours after rainfall | 50 |
Stormwater infiltration device, downgradient ditch | 25 |
Ditch upgradient of tank | 10 |
Driveway or pavement | 5 |
Edge of road easement or right-of-way | 5 |
1 The edge of the watercourse is the natural or levied bank for creeks and rivers. The setback may be less where site conditions prevent migration of wastewater to the water body and/or the tank is demonstrated to be watertight. |
Effluent Application Rate Based on Soil Percolation Rate (application rates may be interpolated if the percolation rate falls between the indicated values): |
Percolation Rate MPI | Application gal/sf/day | |
|---|---|---|
BOD=150 mg/L Conventional | BOD<=30 mg/L ET/Dosed | |
<1 | — | 1.6 |
1 | 1.2 | 1.6 |
5 | 1.2 | 1.6 |
10 | 0.80 | 1.6 |
15 | 0.73 | 1.46 |
20 | 0.66 | 1.32 |
25 | 0.60 | 1.2 |
30 | 0.53 | 1.06 |
35 | 0.48 | 0.96 |
40 | 0.42 | 0.84 |
45 | 0.37 | 0.74 |
50 | 0.31 | 0.62 |
55 | 0.26 | 0.52 |
60 | 0.2 | 0.40 |
90 | — | 0.3 |
90—120 | — | 0.2 |
Design Flow per Bedroom (gallons per day): |
Number of Bedrooms | 1 | 2 | 3 | 4 | 5 | 6 | Per Additional Bedroom |
|---|---|---|---|---|---|---|---|
Standard design flow (gpd) | 250 | 300 | 375 | 450 | 525 | 600 | 75 |
Low flow system (gpd) repair only, with limitations* | 150 | 200 | 250 | 300 | 350 | 400 | 50 |
* Low flow systems require water conservation devices, flow monitoring, deed recordation, annual fee, periodic inspection, and limits on remodels. |
From Leaching Trench and Expansion Area to: | Minimum Permitted Distance in Feet |
|---|---|
Septic tank | 5 |
Property line | 5 |
Foundation, structure, bearing weight, building overhang, ground mount solar panels, utility trenches | 5 |
Private individual water line, stormwater tightline | 10 |
Water main | 25 |
Stream, well, spring, watercoursea, nonpublic water well, well siteb, sinkhole or other karst feature that may rapidly convey water | 100 |
Public water well, if dispersal is 10 ft or less deep | 150 |
Public water well, if dispersal is greater than 10 ft deep | 200, with enhanced treatment and disinfectionc |
Vernal pools, wetlands, lakes, ponds, ocean, or other surface water bodies | 200 |
Drainageway, stormwater infiltration device, or curtain drain | 25 if OWTS dispersal is down-gradient or device only carries water up to 12 hours after significant rain 50 if OWTS dispersal is upgradient or conveyance/device carries stormwater more than 12 hours after significant rain |
Ditch or swale upgradient of dispersal device | 10 |
Steep sloped | 25e |
Embankmente | 4 times height of bank to maximum of 25e |
Pavement or driveway | 5 |
Edge of road easement or right-of-way | 5 |
Swimming pool | 10 |
a The edge of the watercourse is the natural or levied bank for creeks and rivers. |
b Well site would include any well lot or proposed well site. |
c Supplemental treatment components designed to perform disinfection shall provide sufficient pretreatment of the wastewater so that effluent from the supplemental treatment components does not exceed a 30-day average TSS of 30 mg/L and shall further achieve an effluent fecal coliform bacteria concentration less than or equal to 200 Most Probable Number (MPN) per 100 milliliters. |
d Steep slope is a slope of greater than one and one-half feet horizontal to one foot vertical (67%). |
e Fifty feet if slope area is composed of fractured material or if slope area or embankment is intersected by impermeable strata or shallow groundwater. |
Construction Detail | Required Standard |
|---|---|
Width of leaching trench | 18—36 inches maximum |
Standard leaching trench depth | Maximum depth of 4 feet (4 square feet/linear foot infiltrative area)* |
Maximum length of each leaching trench | 100 feet; pressured dosed dispersal systems may have longer trenches |
Slope of leaching trench | Level, no more than 3 inches per 100 feet |
Minimum depth of rock under leaching trench pipe (unless pressure distribution used) | 12 inches |
Rock over leaching trench pipe | 2 inches |
Size of rock or gravel | 0.5 to 2.5 inches |
Minimum spacing of new and old trenches, edge to edge | 3 feet minimum and twice the effective gravel depth up to 8 feet maximum |
Minimum soil cover over leaching trench pipe | 12 inches |
Orientation of leaching trench | Long axes shall be aligned parallel to the ground surface contours and perpendicular to the groundwater gradient as close as possible |
Inspection risers | Installed vertically at each end of each trench, with perforated pipe from the bottom of the trench to the top of the dispersal pipe and solid pipe to the ground surface |
* Replacement systems for repairs on parcels with soils that percolate in the range of six to 60 minutes per inch may use a deeper trench not to exceed 10 feet, and an infiltrative area of up to 10 square feet per linear foot, if constraints on the parcel prevent the use of the standard trench depth. However, in all such instances, the trench shall be as shallow as possible using the maximum lineal feet that can fit on the parcel while still reserving the required expansion area. Enhanced treatment may be required per SCCC § 7.38.095(C). |
Conventional Systems: | |||
|---|---|---|---|
Horizontal Setback to Stream | 25—50 Feet | 50—100 Feet | > 100 Feet |
New system on undeveloped parcel | Not Permitted | Not Permitted | <1 MPI—Not Permitted 1—5 MPI Not permitted in nitrate concern area 1—5 MPI = 20 feet outside nitrate concern area 5—29.9 MPI = 8 feet 30—60 MPI = 5 feet >60 MPI—Not Permitted |
Upgraded system, increase in flow by ADU, bedroom addition or major remodel | Not Permitted | Not Permitted | <1 MPI—Not Permitted 1—5 MPI Not permitted in nitrate concern area 1—5 MPI = 20 feet outside nitrate concern area 5—29.9 MPI = 8 feet 30—60 MPI = 5 feet >60 MPI – Not Permitted |
Repaired system, no increase in flow | Not Permitted | <1 MPI—Not Permitted 1—5 MPI Not permitted in nitrate concern area 1—5 MPI = 20 feet outside nitrate concern area 5—29.9 MPI = 5 feet 30—60 MPI = 5 feet >60 MPI – Not Permitted | <1 MPI—Not Permitted 1—5 MPI Not permitted in nitrate concern area 1—5 MPI = 8 feet outside nitrate concern area 5—29.9 MPI = 5 feet 30—60 MPI = 5 feet >60 MPI – Not Permitted |
Greywater sump | 5 feet | 5 feet | 3 feet |
Enhanced Treatment System a (BOD, TSS, TN <30 mg/L; fecal coliform/E.coli reduction to 200 MPN/100 ml) | |||
|---|---|---|---|
Horizontal setback to stream | 25—50 Feet | 50—100 Feet | > 100 Feet |
New system on undeveloped parcel | Not Permitted | Not Permitted | 2 feet |
Upgraded system, increase in flow by ADU, bedroom addition or major remodel | Not Permitted | 2 feet | 2 feet |
Repaired system, no increase in flow | 4 feet | 2 feet | 2 feet |
Seepage pit—repair/upgrade only | Not Permitted | Not Permitted | 10 feet |
a Enhanced treatment with nitrogen reduction is required for all new, repaired, and replacement OWTS with soils that percolate faster than five minutes per inch in nitrate concern areas (see SCCC § 7.38.183). |
b Groundwater separation less than two feet can only be approved by Regional Water Board. |