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Alameda County, CA Environmental Rules: Stormwater Management (2026)

Significant Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Core rule
Nonstormwater discharge banned
Key exemption
Dechlorinated pool draining allowed
Permit trigger
5,000+ sq ft new impervious surface
Violation
Misdemeanor under § 13.08.120

Summary

Unincorporated Alameda County bans discharging anything but stormwater into its storm drains, creeks or the bay, with narrow exemptions for irrigation runoff, pool draining and similar low-risk flows.

City-specific rules exist: Hayward, San Leandro, Livermore, Fremont, Berkeley, and Oakland have their own stormwater management rules that differ from Alameda County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

Except for those discharges described in subsection B of this section, the discharge of nonstormwater discharges to the waters of the United States or to the county stormdrain system is prohibited.

Source: Alameda Countywide Clean Water ProgramView official code

Full Breakdown

Alameda County Code § 13.08.070 prohibits discharging any nonstormwater material to the waters of the United States or the county stormdrain system in unincorporated Alameda County: enforcing the Clean Water Act and the county's NPDES permit. Narrow exemptions cover things like water-line flushing, landscape irrigation runoff, air conditioning condensate, and dechlorinated swimming pool discharges, so long as they're properly managed. New development or redevelopment creating 5,000 square feet or more of impervious surface must install post-construction stormwater controls and, for construction sites, a stormwater pollution prevention plan under § 13.08.100. Oakland, Berkeley and the county's other cities enforce their own separate stormwater ordinances.

Violations & Fines

Illicit discharge or an unpermitted connection to the county stormdrain system is a misdemeanor under § 13.08.120, and the director can suspend discharge access to stop it.

Frequently Asked Questions

Can I drain my pool into the street?
Yes: dechlorinated swimming pool discharges are exempted under § 13.08.070(B)(2), as long as they're properly managed.
Does this rule apply inside Oakland?
No: this chapter covers unincorporated Alameda County only; Oakland runs its own stormwater ordinance.

Sources & Official References

Other rules in Alameda County

Flood Elevation RequirementsSome RestrictionsErosion ControlSome RestrictionsFlood ZonesSome RestrictionsParking Rules: Commercial & Oversized VehiclesSignificant RestrictionsParking Rules: Preferential Parking DistrictsSome RestrictionsParking Rules: Loading ZonesSome RestrictionsLandscaping Rules: Tree Removal & Heritage TreesSome RestrictionsWater Use Rules: Recycled Water RulesLight RestrictionsHistoric Preservation: Historic-Cultural MonumentsSignificant Restrictions

All Alameda County rules

California rules heatmap·Compare Alameda County to another location·View the California environmental rules overview

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Stormwater Management in Cities Across Alameda County

Oakland, CAFremont, CAHayward, CABerkeley, CASan Leandro, CALivermore, CACastro Valley, CA