Cupertino, CA Environmental Rules: Stormwater Management (2026)

Cupertino Municipal Code Chapter 9.18 implements the Municipal Regional Stormwater NPDES Permit that the San Francisco Bay Regional Water Quality Control Board issued to the City on October 14, 2009. Section 9.18.040 makes it unlawful to discharge anything but stormwater into the City's storm drain system, surface waters, or any location where it would reach a watercourse, unless the Municipal Regional Permit lists it as an exempt or conditionally exempt discharge. The prohibition covers pool water, carwash water, sediment, stockpiled material, rubbish, and hazardous materials left where they threaten to reach a drain.

Categorically allowed discharges are limited to items such as natural spring flows, rising groundwater, and single-family foundation and footing drain water. The Director of Public Works, per Section 9.18.015, administers and enforces the chapter and may delegate that authority to other City staff. Anyone who accidentally discharges a pollutant of concern must notify the Director immediately and follow up with a written statement within five business days under Section 9.18.070. City inspectors respond to reported discharges and require compliance within the time an inspector sets, never more than ten business days after a violation is noted, under Section 9.18.195.

Violations are misdemeanors punishable under Chapter 1.12 per Section 9.18.220, and the City may also pursue civil penalties of up to twenty-five thousand dollars per day for discharges made through illicit connections under Section 9.18.240, or administrative citations under Chapter 1.10 per Section 9.18.260. Penalty funds are deposited into the City's Environmental Storm Management Account.