Santa Clara County, CA Environmental Rules: Stormwater Management (2026)
Key Facts
- Core rule
- No non-stormwater discharge to storm drains
- Construction
- BMPs required, inspected before/after work
- Development
- Stormwater plan required before permits issue
- Enforcement
- Misdemeanor, stop-work notice, nuisance action
Summary
Dumping anything but rainwater into storm drains or waterways in unincorporated Santa Clara County is illegal, and construction or development projects must install BMPs and get stormwater plan approval before permits issue.
Any non-stormwater discharge into any part of the stormwater system and watercourses is prohibited. It is unlawful to throw, deposit, leave, abandon, maintain or keep materials or waste on public or private lands in a manner and place where they may result in a non-stormwater discharge. This section shall not apply to non-stormwater discharged in compliance with an issued individual or any general NPDES permit.
(Ord. No. NS-517.84, 6-25-13; Ord. No. NS-517.87, § 2, 8-26-14)
Sec. B11.5-5. - Exceptions to discharge prohibition. Any discharge regulated under a valid NPDES Permit or Regional Water Quality Control Board Waste Discharge Requirements Permit issued to the discharger, shall be regulated exclusively by the Regional Water Quality Control Board and is exempt from discharge prohibitions established by this division.
Unpolluted non-stormwater discharges which are properly managed and are identified in the most recently adopted version of the NPDES Municipal Stormwater Discharge Phase I or II permits issued to the County of Santa Clara by the San Francisco Bay and Central Coast Regional Water Quality Control Board, may be exempt from the prohibition of discharging non-stormwater, unless they are identified as a source of pollutants to receiving water bodies.
(Ord. No. NS-517.84, 6-25-13)
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 65).
Full Breakdown
Section B11.5-4 bans any non-stormwater discharge into the County's storm drain system and watercourses, and makes it unlawful to leave materials or waste where they could wash into one, unless the discharge is covered by an NPDES permit. Construction sites must install and maintain erosion, sediment, and runoff-control best management practices under the County's NPDES Phase I/II permits, and new development or redevelopment projects can't get a grading, drainage, or building permit until stormwater treatment measures are reviewed and approved by the Office of Land Development Engineering.
Violations & Fines
Violating the discharge prohibition is a misdemeanor under Section B11.5-8, and the County can issue a stop-work notice, recover enforcement costs, and treat the violation as a public nuisance.
Frequently Asked Questions
Can I hose dirty wash water into the street in unincorporated Santa Clara County?
Do new home additions need a stormwater plan?
Sources & Official References
Other rules in Santa Clara County
California rules heatmap·Compare Santa Clara County to another location·View the California environmental rules overview
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