8.7.2 General Requirements

1. In all Watershed Protection Overlays, except F/J-B and E-B, the minimum lot sizes indicated in the following table shall be applied in all new subdivisions unless the subdivision uses the cluster provision in accordance with Sec. 6.7, Cluster Subdivision, or the conservation subdivision provisions of paragraph 6.2.4, Conservation Subdivision.

Minimum Lot Size
Overlay	Rural Tier	Rural Tier – Rural Village	Suburban Tier
M/LR-A	3 acres		20,000 square feet
M/LR-B	3 acres	1 acre	20,000 square feet
F/J-A	3 acres		1 acre
E-A, E-A(2)	Not Applicable		20,000 square feet

2. In the F/J-B and E-B overlays, developers of single-family subdivisions shall comply with the requirements of the underlying zoning district.

1. Any development in a Watershed Protection Overlay shall be subject to limits on the amount of impervious surfaces permitted in accordance with the following table. Development plans, site plans, preliminary plats, and final plats shall clearly identify the amount of existing and proposed impervious surfaces.

Overlay	Low Density Option Impervious Surface Limit		High Density Option Impervious Surface Limit
M/LR-A	6%		Not permitted
M/LR-B	Rural Tier	6%	Not permitted
M/LR-B	Rural Village	12%	24%
F/J-A	Within one-half mile of the normal pool: six percent; Between one-half and one mile from the normal pool: nine percent		Not permitted in the Rural Tier. 40%, for all areas not in the Rural Tier and for those uses allowed in Sec. 4.11.4, Nonresidential Land Use Restrictions; Nonresidential Land Use Restrictions, intensities greater than 25% shall require a Major Special Use Permit pursuant to Sec. 3.9, Special Use Permit.
F/J-B, E-B	24%		70%
E-A, E-A(2)	24%		Not permitted

2. The impervious surface limit provisions of this section can be exceeded through an impervious surface credit transfer. Credit for the impervious surfaces allowed on one or more parcels (“donor parcels”) can be transferred to non-contiguous parcels (“receiving parcels”), such that the amount of impervious surface available for a development project would be the total of what is normally allowed on the receiving parcel plus what is transferred from the donor parcel(s). Impervious surface credit transfer is subject to the following provisions:

a. The donor parcel and receiving parcel shall be located within the same water supply watershed.

b. The impervious surface credit transfer shall not be from a donor parcel in Area B to a receiving parcel in Area A, or from a donor parcel in an F/J-A area with a nine percent limit to a receiving parcel in an F/J-A area with a six percent limit.

c. The portion of the donor parcel which is restricted from development as part of the impervious surface credit transfer shall remain in a vegetated or natural state or used for crop production or pasture provided that best management practices (BMPs) as developed by the Soil and Water Conservation District are utilized. The portion of the donor site restricted from development shall be protected from all future development through use of a permanent conservation easement in favor of either:

(1) Durham County or the City of Durham; or

(2) A land trust or similar conservation-oriented non-profit organization with legal authority to accept such easements (the organization shall be bona fide and in perpetual existence and the conveyance instruments shall contain an appropriate provision for retransfer to the County or City, as appropriate, in the event the organization becomes unable to carry out its functions). If the entity accepting the easement is not the County or City, then a third right of enforcement favoring the County or City, as appropriate, shall be included in the easement.

d. The impervious surface credit transfer shall be reviewed and approved through use of the final plat process pursuant to Sec. 3.6, Subdivision Review, or the site plan process pursuant to Sec. 3.7, Site Plan Review, as applicable.

e. The donor parcel shall be deemed appropriate for acceptance by the County or City, as appropriate, under the Durham County Review Criteria for Acceptance of Conservation Easements for Impervious Surface Transfer.

Where development proposes intensity greater than the maximum authorized by the Low Density Option, engineered stormwater controls shall be used to control stormwater runoff from the first inch of rainfall in order to meet water quality concerns.

1. Unless otherwise approved, ownership of the engineered stormwater controls shall remain with the property owner or a property owner's association, which shall be responsible for the continued care and maintenance of such controls.

2. Engineered stormwater controls shall be designed and constructed in accordance with standards and specifications established by the City Public Works Director or County Engineer, or their designees, as appropriate.

3. Except as allowed in paragraph c below, no building permit shall be issued for a site proposed for development, until:

a. The City Public Works Director or County Engineer, or their designees, as appropriate, has approved plans and specifications for the proposed engineered stormwater controls and the property owner has entered into an Agreement and Covenants or Operation and Maintenance Agreement with the City or County, as appropriate, in accordance with the terms established by either the City Public Works Director or County Engineer, or their designees, as appropriate; and

b. The property owner has posted a performance bond, other surety instrument, or other payment satisfactory to the City or County, as appropriate, in an amount determined by the City Public Works Director or County Engineer, or their designees, as appropriate to assure construction, maintenance, repair, and/or reconstruction necessary for adequate performance of the engineered stormwater controls.

c. For office, institutional, commercial, industrial, and multifamily projects, building permits may be issued; but construction drawing approval, or water or sewer permit approval, shall be withheld until compliance with paragraphs a and b above.

d. The Agreement and Covenants or Operation and Maintenance Agreement required under paragraph a, above, may be required prior to site plan or preliminary plat approval.

4. No certificate of compliance shall be issued for any structure constructed within a site proposed for development, other than as allowed below, until the City Public Works Director or County Engineer, or their designees, as appropriate, has approved construction of the engineered stormwater controls and after review and approval of submitted “as-built” drawings. Notwithstanding this requirement, the Stormwater Division of the City may allow for delay in approval of construction of stormwater controls and submission and approval of as-built drawings for single family housing, duplexes, townhouses, and detached rowhouses) and other developments requiring multiple certificates of occupancy in accordance with adopted policies of the City.

Riparian buffers are required in accordance with Sec. 8.5, Riparian Buffer Protection Standards.

Except as indicated below, wastewater treatment facilities shall be prohibited in all Watershed Protection Overlays.

a. Individual on-site ground absorption systems shall be permitted, subject to the approval of the Durham County Health Department or the State of North Carolina, as applicable.

b. A spray irrigation wastewater treatment system to serve a single-family house shall be permitted, provided that:

(1) The owner enters into a written agreement with the Durham County Health Department which:

(a) Provides for Health Department access to the property for the purpose of monitoring the system during its construction and operation; and

(b) Provides that the owner and certified operator shall provide to the Health Department copies of any and all applications, plans, permits, reports and any other documents concerning but not limited to the permitting, system, design, construction, operation, monitoring or repair of the system.

(2) The owner shall not act as the certified operator for a spray irrigation system to be installed on his or her property.

c. Publicly-owned wastewater treatment facilities, and replacement and expansions of such facilities, shall be allowed in F/J-B and E-B overlays.

d. In the County jurisdiction, wastewater treatment facilities may be permitted in the F/J-A Overlay through the issuance of a Major Special Use Permit pursuant to Sec. 3.9, Special Use Permit, subject to the restrictions described in Sec. 12.7, Water and Sanitary Sewer Systems. This requirement shall also apply within the City jurisdiction unless the system has been approved by the State.

a. Except in the Rural Tier, public and private sanitary sewer lines, force mains, and pump stations shall be permitted within all Watershed Protection Overlays. Public and private pump stations shall be equipped with the following safety features:

(1) Battery-backed alarm systems activated by pump failure or power outage, connected by an automatic dialer to a 24-hour maintenance service approved by the City Public Works Director or County Engineer, or their designees, as appropriate.

(2) Provision for connection of a portable generator. The City Public Works Director or County Engineer, or their designees, as appropriate, may require the pump station to be equipped with on-site, stand-by power.

b. Within the Rural Tier, new public or private sanitary sewer lines or outfalls, including necessary force mains and pump stations, may be permitted within the Watershed Protection Overlays subject to City Council or Board of Commissioners approval, as appropriate:

(1) To serve an existing use or structure for which a health hazard has been documented by the County Health Department or the State of North Carolina; or

(2) If associated with a wastewater treatment facility permitted pursuant to paragraph 1, Wastewater Treatment, above.

c. In considering such extensions, all reasonable alternatives shall be considered prior to a decision to extend the sewer services. All service connections, installed in accordance with the North Carolina Plumbing Code, shall be permitted only in accordance with Article III, Water and Sewer Main Extensions, of Chapter 70, Utilities, of the Durham City Code.

1. Prior to site plan approval, an Emergency Contingency Plan shall be prepared and submitted through the Planning Department to the Durham County Fire Marshall and the Water Management Director for review and approval. The Emergency Contingency Plan shall be prepared in accordance with the requirements in the Superfund Amendments and Reauthorization Act (SARA), Title III and shall be updated annually. In addition, the Emergency Contingency Plan shall include:

a. A site plan showing buildings and the locations of points of storage, transfer and use of nuclear and hazardous materials;

b. A list of nuclear and hazardous materials kept on-site in any quantities;

c. The location of spill control valves on any bridges and causeways; and

d. The person responsible for on-site spill control and containment, and the appropriate means of contacting that person on a 24-hour basis.

2. Any container or tank used to store hazardous materials shall be equipped with leak detection devices and shall be double-walled or have other secondary containment features.

3. Points of storage, transfer and use of substantial quantities of hazardous materials shall be protected by a dike or comparable containment structure, constructed of a material resistant to hazardous material the dike or structure is designed to contain. The dike or structure shall be sized to handle at least the maximum amount of material to be stored or used and shall be constructed and installed in a manner to exclude rainwater and stormwater runoff.

4. All floor drains that could collect hazardous materials shall be connected to a corrosion resistant tank or catch basin sized to handle the maximum amount of hazardous material to be stored or used. These floor drains shall not be open to the site's natural drainage system and discharges to the site's storm drainage system or to adjacent surface waters shall be prohibited.

5. Points of storage, transfer and use of hazardous or nuclear materials shall have roof coverage.