To: Board of Supervisors
From: Warren Lai, Public Works Director/Chief Engineer
Report Title: Introduction of Ordinance No. 2025-01 to amend Division 1014 Stormwater Management and Discharge Control, Countywide.
☒Recommendation of the County Administrator ☐ Recommendation of Board Committee
RECOMMENDATIONS:
INTRODUCE 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 (RWQCB), Order No. R2-2022-0018, NPDES Permit No. CAS612008; WAIVE reading; and FIX February 4, 2024, for adoption.
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 control board issued under the NPDES program. The RWQCB issued two prior permits regulating stormwater discharges by Contra Costa County (County) - NPDES Permit No CAS612008, Order No. R2-2009-0074, and NPDES permit 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 the 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.
Public Works Department staff recommend that the Board approve introducing Ordinance No. 2025-01 to ensure that the County can regulate new developments and comply with the new requirements of the MRP, waive reading of the ordinance, and fix February 4, 2024, for adoption. Adoption of the ordinance will ensure that the County will be in compliance with the MRP. When the ordinance is brought back for adoption, the Board will be asked to approve a C.3 Guidebook, which will assist development applicants with complying with the MRP and the new requirements enacted by the ordinance.
CONSEQUENCE OF NEGATIVE ACTION:
Introduction of the ordinance is required before the Board can consider adopting the ordinance. 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.