To: Board of Supervisors
From: Warren Lai, Public Works Director/Chief Engineer
Report Title: Adoption of Ordinance No. 2025-01 to amend Division 1014 Stormwater Management and Discharge Control and a Resolution approving a new C.3 Guidebook, Countywide.
☒Recommendation of the County Administrator ☐ Recommendation of Board Committee
RECOMMENDATIONS:
ADOPT Ordinance No. 2025-01 to amend Division 1014 of the Ordinance Code (Stormwater Management and Discharge Control) to enact new stormwater source control, site design, and stormwater treatment requirements required by the new Municipal Regional Stormwater National Pollutant Discharge Elimination System (NPDES) Permit issued by the California Regional Water Quality Control Board, San Francisco Bay Region, Order No. R2-2022-0018, NPDES Permit No. CAS612008.
ADOPT the attached Resolution to approve a new C.3 Guidebook to assist new development projects to comply with the requirements of the new NPDES permit and Division 1014 of the Ordinance Code.
DETERMINE that the activity is not subject to the California Environmental Quality Act (CEQA), pursuant to Sections 15061(b)(3) of the CEQA Guidelines.
DIRECT the Director of the Department of Conservation and Development to file a Notice of Exemption with the County Clerk.
AUTHORIZE the Public Works Director, or designee, to arrange for payment of a $25 fee to the Department of Conservation and Development for processing, and a $50 fee to the County Clerk for filing the Notice of Exemption.
FISCAL IMPACT:
This project is funded by 100% Stormwater Utility Assessment Funds. Project No. 7517-6W7087
BACKGROUND:
The federal Clean Water Act (33 U.S. C., § 1251, et seq.) and the state Porter-Cologne Water Quality Control Act (Cal. Wat. Code, § 13000, et seq.) prohibit discharges of stormwater without a permit from the appropriate California regional water quality board issued under the NPDES program. The California Regional Water Quality Control Board, San Francisco Bay Region (RWQCB) issued two prior permits regulating stormwater discharges by Contra Costa County (County) - Permit No CAS612008, Order No. R2-2009-0074, issued October 14, 2009, and NPDES permits CAS612008, issued November 19, 2015 (Order No. R2-2015-0049), as amended by Order R2-2019-0004, issued February 13, 2019. The permits regulated stormwater discharges by the County and required the County to impose discharge requirements on developments. After each order was issued, the County amended Division 1014 of the Ordinance Code (Stormwater Management and Discharge Control) to impose stormwater management and discharge requirements on new developments consistent with the permit requirements.
In 2020, the Contra Costa Clean Water Program, which includes the County, the County Flood Control and Water Conservation District, and all municipalities in the County, applied to the RWQCB for a new municipal stormwater permit to discharge stormwater runoff from storm drains and watercourses in the jurisdiction. On May 11, 2022, the RWQCB issued new Municipal Regional Stormwater NPDES Permit No. CAS612008, Order No. R2-2022-0018 (MRP) to regulate discharges of stormwater by the County and other members of the Contra Costa Clean Water Program. Section C.3 of the MRP requires the County and other members of the Contra Costa Clean Water Program to impose new source control, site design, and stormwater treatment requirements on new development projects that meet specified criteria.
Ordinance No. 2025-01 will amend Division 1014 of the County Ordinance Code to require new developments in the unincorporated County to comply with the requirements of Section C.3 of the MRP. Generally, Ordinance No. 2025-01 makes the following changes to Division 1014:
• Clarifies what constitutes prohibited discharges.
• Requires the following new development projects to comply with Section C.3 of the MRP:
o New development projects, previously undeveloped that create 5,000 square feet or more of impervious surfaces,
o Development projects on previously developed sites that create or replace 5,000 square feet or more of impervious surface. Some exceptions are individual single-family home projects less than 10,000 square feet, interior models, routine maintenance, public road and trail projects, public works projects less than 5,000 contiguous square feet of impervious surface, and some pavement maintenance practices,
o Construction of new streets or roads, except sidewalks or bicycle lanes in the project that direct stormwater to adjacent vegetated areas, certain impervious trails, sidewalks, bicycle lanes or trails built as pervious pavement systems, State of California highway projects,
o Public and other streets or roads that create or replace one contiguous acre or more of impervious surface, and
o Single-family home projects with just one home, including an accessory dwelling unit that creates or replaces 10,000 square feet or more of impervious surface and is not part of a larger development or redevelopment plan.
• Exempts certain unpolluted discharges from complying with the requirements. Unpolluted discharges include discharges from residential foundation, crawl space, or footing drains, and groundwater pumped for drinking water purposes, among others.
• Clarifies that developments approved earlier are required to comply with the requirements in effect at the time the developments were approved.
California Environmental Quality Act (CEQA). The Department of Conservation and Development staff have determined that the approval of Ordinance No. 2025-01 is exempt from CEQA environmental review under CEQA Guidelines Section 15061(b)(3), general rule of applicability. This exemption applies to projects that will have no significant effect on the environment. Adopting the ordinance and implementing the MRP will not adversely impact the environment, but will actually improve the environment by treating rainwater that flows over impervious surfaces.
Ordinance No. 2025-01 was introduced on January 21, 2025. Public Works Department staff recommend that the Board adopt Ordinance No. 2025-01 to ensure that the County can regulate new developments and comply with the new requirements of the MRP. Staff also recommend that the Board adopt the accompanying Resolution to approve a new C.3 Guidebook, which will assist development applicants with complying with the MRP and the new requirements enacted by Ordinance No. 2025-01.
CONSEQUENCE OF NEGATIVE ACTION:
If this ordinance is not adopted, the County will be unable to meet its obligations under the MRP under the NPDES Program and could be subject to fines and other penalties imposed by the regional water quality control board.
THE BOARD OF SUPERVISORS OF CONTRA COSTA COUNTY, CALIFORNIA
and for Special Districts, Agencies and Authorities Governed by the Board
body
IN THE MATTER OF: APPROVE the Contra Costa Clean Water Program Stormwater C.3 Guidebook, Stormwater Quality Requirements for Development Applications.
WHEREAS, The Board of Supervisors of Contra Costa County RESOLVES that:
WHEREAS, the federal Clean Water Act (33 U.S. C., § 1251, et seq.) and the state Porter-Cologne Water Quality Control Act (Wat. Code, § 13000, et seq.) prohibit discharges of stormwater without a permit from the appropriate California regional water quality board under the National Pollutant Discharge Elimination System (NPDES) program; and
WHEREAS, Contra Costa County, the Contra Costa County Flood Control and Water Conservation District, and the Cities of Antioch, Brentwood, Clayton, Concord, El Cerrito, Hercules, Lafayette, Martinez, Oakley, Orinda, Pinole, Pittsburg, Pleasant Hill, Richmond, San Pablo, San Ramon, Walnut Creek, and the Towns of Danville and Moraga, established the Contra Costa Clean Water Program; and
WHEREAS, the Contra Costa Clean Water Program applied for and was issued a municipal regional stormwater NPDES permit by the California Regional Water Quality Control Board for the San Francisco Bay Region, Order No. R2-2022-0018, NPDES Permit No. R2-2022-0018, issued May 11, 2022 (the “Municipal Regional Stormwater Permit”); and
WHEREAS, the Municipal Regional Stormwater Permit requires the implementation of selected Best Management Practices (BMPs) to minimize or eliminate pollutants from entering waterways; and
WHEREAS, pursuant to the Municipal Regional Stormwater Permit, the County Board of Supervisors adopted Ordinance No. 2025-01 to amend Division 1014 of the Ordinance Code to codify permit requirements that will be imposed on new developments to ensure the County complies with the permit requirements; and
WHEREAS, the Contra Costa Clean Water Program created a Low Impact Development program to comply with Municipal Regional Stormwater Permit, Provision C.3, New and Redevelopment, and developed an accompanying Stormwater C.3 guidebook.
NOW, THEREFORE, BE IT RESOLVED that the Contra Costa County Board of Supervisors does hereby APPROVE the Contra Costa Clean Water Program Stormwater C.3 Guidebook, Stormwater Quality Requirements for Development Applications, attached hereto.