[Zoning Order §16.460, 4-2-2008]
A. 
Permanent survey monuments shall be provided in accordance with the current Minimum Standards for Property Boundary Surveys for Suburban Class Property, as set forth by the Missouri Department of Natural Resources, Division of Geology and Land Survey and rules promulgated by the Missouri Board for Architects, Professional Engineers and Land Surveyors effective December 30, 1994.
B. 
Semi-permanent markers shall be placed at all lot corners not marked by permanent survey monuments and at all points where street lines intersect the exterior boundaries of the subdivision. These corner pins or crosses shall be required to be installed within twelve (12) months of the date the plat is recorded.
C. 
Prior to submittal of a preliminary plat, the applicant shall place temporary markers that identify the property corners along the road frontage and the approximate location of the intersecting streets.
D. 
The outboundary corners of any major subdivision or site development located within one-half (½) mile of either a NGS or MoGRS point shall be tied into the State Plane Coordinate System in accordance with the Missouri Minimum Standards for Property Boundary Surveys. All other subdivisions or developments are encouraged to tie into this system. All major subdivisions are encouraged to install monumentation that will have the effect of expanding the State Plane Coordinate System. All other subdivisions or developments are encouraged to provide these points.
E. 
When available, the subdivider shall submit copies electronic form in a multi-media format used by the County.
[Zoning Order §16.470, 4-2-2008]
Classification of streets shall be as shown in Article VII. The required street improvements shall be determined by Articles VII and XVI and other pertinent requirements of this UDO. In addition to Section 400.5670, the subdivider shall make provisions in the trust indenture or declaration of covenants to provide for the long-term maintenance of the streets.
[Zoning Order §16.480, 4-2-2008]
A. 
Sidewalks shall be constructed and installed in conformity with the minimum design standards of this Article and with the design standards set forth in Article VII. The following additional regulations shall apply to the construction of sidewalks:
1. 
Construction.
a. 
The sidewalks shall be constructed and installed by the builder prior to the issuance of an occupancy permit. Should construction or installation of the sidewalks be impossible because of weather or other conditions, the builder shall provide the County satisfactory surety in the form of cash or an irrevocable bank letter of credit for one hundred percent (100%) of the construction cost of said sidewalk prior to the issuance of the occupancy permit in accordance with Section 400.5190 of this Article.
b. 
When sidewalks are required adjacent to common area tracts or any other such land where no structure will be built, the developer shall construct the sidewalk at the time the street is constructed.
2. 
Coordination with curbs and gutters. For property on which curbs and gutters are required prior to occupancy and sidewalks are required by this Article, installation of sidewalks will not be required until curbs and gutters are installed and the provisions of Section 400.5530 above are satisfied.
[Zoning Order §16.490, 4-2-2008]
A. 
All buildings, structures and uses of land in the unincorporated area of Jefferson County shall hereafter be required to have an adequate, safe and sanitary disposal system for all human, domestic and industrial wastes. For the purposes of these regulations, disposal of sewage or other liquid wastes shall conform to the methods outlined herein:
1. 
Central sanitary sewer system. Where an approved and adequate public or privately owned central sanitary sewer system is reasonably accessible, that substantially meets the requirements of the Missouri Department of Natural Resources, the subdivider/developer shall connect with such sanitary sewer and provide adequate sewer lines to each lot. Sewer extensions shall be constructed as approved by the Department of Natural Resources and the appropriate public sewer district or private sewer company. A developer shall be required to meet the requirements of the utility provider.
2. 
Package treatment facility. Where an approved public or privately owned central sanitary sewer system is not reasonably accessible, the use of a package treatment facility may be permitted, provided such facilities are approved by the Department of Natural Resources and are constructed in accordance with the regulations and requirements of the Department of Natural Resources.
3. 
On-site sewage disposal system. Individual sewage disposal systems may be used in subdivisions where central sanitary sewer systems or other similar means of disposal are not feasible, provided each lot is two (2) acres or more in area in those locations where a soil morphology report, the soil depth and the site slope indicate that the soil characteristics and site conditions are suitable for the type of individual sewage disposal system proposed. Individual sewage disposal systems shall be designed and installed in accordance with the standards, criteria, procedures and approval of the Department of Natural Resources and/or the County. The County shall have jurisdiction over final approval and inspection of all individual sewage disposal systems.
[Zoning Order §16.500, 4-2-2008]
Easements for sanitary sewers shall be extended to the subdivision boundary line to serve adjacent property. These sewers shall be of adequate size to serve the upstream basin, if required by the controlling authority and such authority pays for any upsizing of the facility.
[Zoning Order §16.510, 4-2-2008; Resolution 1-14-2010A Exh. A, 1-14-2010; Ord. No. 10-0145 §§1 — 2, 2-18-2010]
A. 
In addition to the installation of drainage courses, curbs and gutters along the streets as required by this Article, an adequate stormwater drainage system shall be required. This system shall include all necessary pipes, culverts, intersectional drains, cross drains, drops, inlets, bridges and other accessory structures and improvements to provide for the proper drainage of all surface water.
B. 
Drainage improvements (including detention) shall be designed using the following methods to determine flow quantities: a TR-55 Analysis shall be used to design detention; and the Rational Method shall be used to design piping systems. The Jefferson County Erosion and Sediment Control/Stormwater Management Design Manual details the rainfall frequency and time of concentration to be used when designing drainage improvements. Stormwater calculations shall be submitted with the improvement plans to the Planning Division for distribution and approval.
[Ord. No. 20-0406, 9-29-2020]
C. 
Unless excepted by these regulations, stormwater shall be controlled on site by detention basins for all subdivisions/developments. The detention basins shall be sized based upon the differential runoff of the planned development versus the predevelopment conditions. The stormwater shall be released at the rate of the existing predeveloped rate, while the overflow structure and downstream pipes shall be sized to carry the total tributary upstream watershed. Maximum discharge shall be designed to take place under total anticipated design-head conditions. The stormwater drainage system shall be separate and independent from the sanitary sewer system. The plans and specifications shall be prepared and submitted as required in Articles IV and X and shall be approved by as a part of the development plan as provided herein.
D. 
Stormwater detention is not required in the following instances, unless failure to provide these improvements would result in substantial loss of property or potential loss of life:
1. 
Residential subdivisions with a density of two and one-half (2.5) dwelling units per gross acre or less and with eight (8) or fewer lots.
2. 
Residential subdivisions with a density of between two and one-half (2.5) and four (4.0) dwelling units per gross acre and with five (5) or fewer lots.
3. 
The smallest residential lot is four (4) or more acres in size.
4. 
Existing non-residential developments or residential structures converting to a non-residential use, where the additional impervious coverage to be created does not exceed twelve thousand (12,000) square feet in size, with the following condition:
a. 
Low-impact stormwater management practices are required to mitigate the additional runoff created by the additional impervious coverage.
b. 
No adverse stormwater impacts created.
All impervious coverage created prior to adoption of the UDO will be exempt from the twelve thousand (12,000) square foot calculation. Any impervious surface created after adoption of the UDO, with or without a permit, will be included in the calculation of impervious coverage.
E. 
Open drainage swales or ditches may be permitted in subdivisions where all lots are greater than two (2) acres in size or in planned districts and in accordance with an approved stormwater management plan.
[Zoning Order §16.520, 4-2-2008]
A. 
Public Water Supply. Where a public water supply system is reasonably accessible, said water supply shall be made available by the subdivider to each lot within the subdivision/development, including a connection to each lot and appropriately spaced fire hydrants. The water supply system shall conform to the standards and requirements of the Department of Natural Resources and the public water district having jurisdiction in the area. Spacing and location requirements of the fire protection system must be approved by the local entity having jurisdiction.
B. 
Private Water Supply. In the absence of a public water supply system, private wells shall be constructed either by the subdivider or subsequent lot owner or a connection to a private water supply system shall be provided by the subdivider so that an adequate supply of potable water will be available to every lot within the subdivision/development. Private water wells and private water supply systems shall confirm to the standards and requirements established by the Division of Geology and Land Survey of the Department of Natural Resources. All private wells shall be registered with the Division of Geology and Land Survey as provided by law.
[Zoning Order §16.540, 4-2-2008; Resolution 1-14-2010A Exh. A, 1-14-2010; Ord. No. 10-0145 §§1 — 2, 2-18-2010]
All street improvements shall be constructed in accordance with Article VII of this UDO. In the event this UDO lacks necessary detail for a particular improvement, the improvement shall be constructed in accordance with the current editions of the "St. Louis County Standard Specifications for Highway Construction" and the "Design Criteria for the Preparation of Improvement Plans". If unaddressed by St. Louis County, then the improvement shall be constructed in accordance with the latest edition of the "Standard Plans and Specifications for Highway Construction and the Missouri Highway and Transportation Commission" in effect as of the date of the adoption of this UDO as stated in Section 400.110. Alternate standard drawings and material specifications may be approved by the Planning Commission.
[Zoning Order §16.550, 4-2-2008]
A. 
Construction of an improvement project may commence only after a minimum of twenty-four (24) hours subsequent to the following requirements being fully met:
1. 
Approval of the improvement plan or site development plan;
2. 
All fees are paid according to the Jefferson County Fees Schedule for Planning and Zoning Activities as set out in Chapter 401 of this Code;
3. 
A preconstruction meeting has been conducted on site with a representative from the County and the developer (utility companies are encouraged but not required to attend);
4. 
A land disturbance permit has been issued in accordance with the procedures set forth in Chapter 505, Article II, Sections 505.130 et seq., of this Code; and
5. 
The Planning Division has been notified a minimum of twenty-four (24) hours prior to anticipated commencement of construction.
[Zoning Order §16.560, 4-2-2008]
A. 
Prior to starting any of the work covered by any improvement plans required herein, after approval thereof, a schedule shall be established for inspection of the proposed work, sufficient to assure compliance with the plans and specifications as approved.
B. 
A duly authorized representative of the County shall make inspections of construction within the subdivision/development. Other improvements associated with the approved improvement plans may also be inspected. A minimum of twenty-four (24) hours' notice shall be given to the authorized representative regarding any requested inspection.