Lot Coverage Limits: Castro Valley vs San Leandro
How do lot coverage limits rules compare between Castro Valley, CA and San Leandro, CA?
Castro Valley and San Leandro have similar restriction levels.
Castro Valley, CA
Alameda County
Unincorporated Alameda County limits maximum lot coverage to 35-45 percent in residential zones under Title 17. Coverage includes all structures with roofs, with some exemptions for uncovered decks and pervious surfaces.
View full Castro Valley rules →San Leandro, CA
Alameda County
San Leandro RS zones typically cap building lot coverage at 40%. Impervious surface limits apply under Bay Area C.3 stormwater standards.
View full San Leandro rules →Key Facts Comparison
| Fact | Castro Valley | San Leandro |
|---|---|---|
| Typical R-1 coverage | 40 percent maximum | - |
| Hillside zones | Often 35 percent | - |
| Uncovered decks | Under 30 inches exempt | - |
| ADU exception | 800 sf exempt per state law | - |
| FAR overlay | Applies in hillside districts | - |
| RS coverage | - | ~40% max |
| RM coverage | - | 50-60% |
| ADU exemption | - | 800 sq ft state rule |
| C.3 threshold | - | 2,500 sq ft impervious |
| Calculation | - | Roof footprint / net lot |
Highlighted rows indicate differences between cities.
Castro Valley FAQ
Does my driveway count toward lot coverage?
No. Driveways and paved walkways are not structures. However, some zones have separate impervious surface limits that include paving.
How do I find my coverage limit?
Check your zoning designation on the Alameda County Planning parcel map, then reference Title 17 for that specific zone.
San Leandro FAQ
Do patios count toward lot coverage?
Unroofed patios typically don't count, but they do count toward impervious surface under C.3.
Can I max coverage with an ADU?
Yes. State law guarantees an 800 sq ft ADU even when coverage caps are exceeded.
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