Contra Costa County Municipal Code Ch. 1014-2 General Provisions

(a) The intent of this division is to protect and enhance the water quality of the county's unincorporated area watercourses pursuant to and consistent with the Porter-Cologne Water Quality Control Act (Water Code Section 13000 et seq.), the Federal Clean Water Act (33 U.S.C. Section 1251 et seq.) and applicable implementing regulations.

(b) This division also carries out the conditions in the county's National Pollutant Discharge Elimination System (NPDES) permits that require implementation of appropriate source control and site design measures and stormwater treatment measures for new development and redevelopment projects that create or replace impervious surface in amounts that meet or exceed certain thresholds.

(c) It is the purpose of the board of supervisors in enacting this division to protect the health, safety and general welfare of the citizens of the unincorporated areas by:

(1) Eliminating, to the maximum extent practicable, illicit stormwater discharges to the stormwater system, pollutants of which otherwise would degrade the water quality of local streams.

(2) Minimizing increases in nonpoint source pollution caused by stormwater runoff from development that otherwise would degrade local water quality.

(3) Controlling the discharge to the county's stormwater system from spills, dumping, or disposal of materials other than stormwater.

(4) Reducing stormwater runoff rates and volumes and nonpoint source pollution whenever possible through stormwater management controls and ensuring that these management controls are properly maintained and pose no threat to public safety.

(5) Promoting no adverse impact (NAI) policies as developed by the Federal Emergency Management Agency (FEMA) and the Association of State Floodplain Managers (ASFPM), to the maximum extent practicable, in an effort to minimize the adverse impact of new development on stormwater quality or quantity.

(Ord. No. 2025-01, § II, 2-4-25; Ord. 2005-01 § 2, 96-21 § 3).

As used in this division, the following words and phrases have the following meanings. Words and phrases in this division not otherwise defined shall be interpreted as defined in the regulations issued by the U.S. Environmental Protection Agency to implement the provisions of the Federal Clean Water Act, and as defined by the State Water Resources Control Board to implement the Porter-Cologne Water Quality Control Act:

"Authorized county employee(s)" means those individuals designated by the director.

"Best management practices" or "BMPs" include both structural devices and operational practices and procedures. "Structural BMPs" are devices, measures, or stormwater management facilities or activities that help to meet development runoff requirements at the premises. "Operational BMPs" include schedules of activities, prohibitions or practices, general good housekeeping, pollution prevention practices, maintenance procedures, and other management practices that prevent or reduce the discharge of pollutants directly or indirectly to watercourses, water bodies and wetlands.

"County's NPDES permits" means the NPDES permits issued jointly to Contra Costa County and other public agencies by the San Francisco Bay Regional Water Quality Control Board and the Central Valley Regional Water Quality Control Board, or any of them, whichever is applicable. County's NPDES permits include CAS612008 and its successors, its predecessors (Permit Nos. CAS0029912 and CAS0083313), and any and all amendments to and reissuances of these NPDES permits.

"Development" as used in this division means on land, in or under water, the placement or erection of any solid material or structure; the discharge or disposal of any dredged material or of any gaseous, liquid, solid or thermal waste; the grading, removing, dredging, mining or extraction of any materials; any change in the density or intensity of use of land, including, but not limited to, a subdivision established pursuant to the Subdivision Map Act (commencing with Section 66410 of the Government Code), and any other division of land; any change in the intensity of use of water, or of access thereto; any construction, reconstruction, demolition, or alteration of the size of any structure, including any facility of any private, public, or municipal utility; and the removal or harvesting of major vegetation other than for agricultural or public agency routine maintenance purposes.

"Development runoff requirements" means the provisions in the county's NPDES permits that contain performance standards to address both the construction and post- construction phase impacts of new projects and redeveloped projects on stormwater quality. These requirements are in provision C.3 of the county's NPDES permits.

"Director" means the director of public works or the director's designee.

"Guidebook" means the most recent version of the Contra Costa Clean Water Program Stormwater C.3. Guidebook approved by the board of supervisors by resolution.

"Illicit discharge" means any discharge to the county's stormwater system that is not composed entirely of stormwater, except for a discharge in compliance with an NPDES permit.

"NPDES" means the National Pollutant Discharge Elimination System, established by the Federal Water Pollution Control Act, as amended, also known as the Clean Water Act (33 U.S.C. Section 1251 and following).

"Pollutant" means any material other than stormwater discharged into the waterways or stormwater system, including, but not limited to, petroleum products or by-products; solid waste; incinerator residue; sewage; sewage sludge; heat; chemical waste; biological materials; radioactive materials; wrecked or discarded equipment; rock; sand; soil; or industrial, municipal or agricultural waste.

"Premises" means any building; structure; facility; land or portion of land whether improved or unimproved; or installation, including a building's grounds or other appurtenances; and adjacent sidewalks and parking areas.

"Responsible person" means the owner or occupant of any premises or any person who engages in any activity from which there is or may be a discharge prohibited by Section 1014-4.006, or any person who releases pollutants to the county's stormwater system.

"Stormwater" water runoff generated when precipitation from rain and snowmelt events flow over land or impervious surfaces without percolating into the ground.

"Stormwater management facility" means any device designed to detain, retain, filter or infiltrate stormwater.

"Stormwater control plan" means a plan that meets those criteria contained in the most recent version of the Contra Costa Clean Water Program Stormwater C.3. Guidebook.

"Stormwater facilities operation and maintenance plan" means a county approved document detailing operation and maintenance requirements for stormwater management facilities incorporated into a project.

"Stormwater system" means that system of facilities (man-made or natural) by which stormwater may be conveyed, including flood control channels, any roads with drainage systems, city streets, catch basins, curbs, gutters, ditches, improved channels, storm drains, or storm drain system, which are not part of a publicly owned treatment works ("POTW") as that term is defined in 40 CFR Section 122.2.

(Ord. No. 2025-01, § II, 2-4-25; Ord. No. 2024-23, § III(Exh. A), 12-3-24; Ord. 2005-01 § 2, 96-21 § 3).

The director or the director's designee shall administer this division for the county.

(Ord. No. 2025-01, § II, 2-4-25; Ord. No. 2024-23, § III(Exh. A), 12-3-24; Ord. 2005-01 § 2, 96-21 § 3).