Lot Coverage Limits: Castro Valley vs Hayward
How do lot coverage limits rules compare between Castro Valley, CA and Hayward, CA?
Castro Valley and Hayward 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 →Hayward, CA
Alameda County
Hayward limits lot coverage by buildings to roughly 40% in single-family zones. Impervious surface totals including driveways are regulated through stormwater and landscape standards.
View full Hayward rules →Key Facts Comparison
| Fact | Castro Valley | Hayward |
|---|---|---|
| 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% typical |
| Multi-family | - | FAR-based instead |
| Impervious | - | C.3 over 2,500 sf |
| ADU exemption | - | Partial per state law |
| Low decks | - | Under 30 in excluded |
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.
Hayward FAQ
Does my patio count toward lot coverage?
Hard impervious patios count toward stormwater surface limits; open decks under 30 inches high are usually exempt from building coverage.
Will an ADU push me over coverage?
State ADU law limits local agencies from denying ADUs over coverage; ADUs up to 800 sf are typically protected.
Compare other topics
See how Castro Valley and Hayward compare on other ordinance categories.
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