Stormwater Management: Castro Valley vs San Leandro
How do stormwater management rules compare between Castro Valley, CA and San Leandro, CA?
Castro Valley and San Leandro have similar restriction levels.
Castro Valley, CA
Alameda County
Alameda County complies with SF Bay Regional Water Board MRP 3.0. Projects disturbing 10,000 sf or more must incorporate Low Impact Development treatment per Provision C.3.
View full Castro Valley rules →San Leandro, CA
Alameda County
San Leandro is co-permittee under Bay Area Municipal Regional Stormwater NPDES Permit. C.3 treatment required for projects creating 2,500+ sq ft impervious.
View full San Leandro rules →Key Facts Comparison
| Fact | Castro Valley | San Leandro |
|---|---|---|
| Permit | MRP 3.0 (SF Bay Water Board) | - |
| C.3 threshold | 10,000 sf impervious | 2,500 sq ft impervious |
| Single-family | 2,500 sf reduced threshold | - |
| Hydromodification | Over 1 acre | - |
| Local agency | Alameda Clean Water Program | - |
| Regulator | - | SF Bay RWQCB MRP |
| Hydromod | - | Over 10,000 sq ft |
| Illicit discharge | - | Up to $10,000/day |
| Local code | - | SLMC Title 7 |
Highlighted rows indicate differences between cities.
Castro Valley FAQ
Do I need stormwater treatment for my home addition?
Only if the project creates or replaces 2,500 square feet or more of impervious surface on single-family lots. Most small additions fall below this threshold but still must avoid illicit discharges.
Can I wash my car in the driveway?
Soapy runoff to storm drains is an illicit discharge. Use commercial car washes that recycle water or wash on gravel or lawn where runoff soaks in rather than entering the street.
San Leandro FAQ
Can I wash my car in the driveway?
Use biodegradable soap and minimize runoff. Commercial car washes are preferred since they capture wastewater.
What is C.3?
Provision C.3 of the Bay Area Stormwater Permit requires on-site treatment of stormwater for projects meeting impervious area thresholds.
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