Lot Coverage Limits: Berkeley vs Castro Valley
How do lot coverage limits rules compare between Berkeley, CA and Castro Valley, CA?
Castro Valley has fewer restrictions than Berkeley.
Berkeley, CA
Alameda County
Berkeley R-1 zones limit main building lot coverage to 40 percent and total structure coverage to 50 percent, with ADUs and SB 9 units subject to state-law overrides.
View full Berkeley rules →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 →Key Facts Comparison
| Fact | Berkeley | Castro Valley |
|---|---|---|
| R-1 main building | 40% max coverage | - |
| R-1 total | 50% max coverage | - |
| Typical FAR | 0.4 to 0.6 | - |
| ADU override | 800 sq ft minimum | - |
| Code | Title 23 | - |
| 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 |
Highlighted rows indicate differences between cities.
Berkeley FAQ
Does a detached garage count toward coverage?
Yes, all roofed structures count, though ADU state law exempts one 800 sq ft unit from local coverage caps.
Are patios counted?
Unroofed patios generally do not count for lot coverage but may count for impervious surface stormwater limits.
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.
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