Lot Coverage Limits: Altadena vs Pasadena
How do lot coverage limits rules compare between Altadena, CA and Pasadena, CA?
Altadena and Pasadena have similar restriction levels.
Altadena, CA
Los Angeles County
Altadena R-1 max Gross Structural Area (GSA) and lot coverage = (0.25 × net lot area) + 1,000 sq ft, never exceeding 9,000 sq ft total (Altadena CSD 22.306.070.A.4).
View full Altadena rules →Pasadena, CA
Los Angeles County
Lot coverage in Pasadena varies by zoning district under Title 17. In hillside overlay districts, gross floor area includes covered parking, habitable attic, and basements. House size limited to 35% above median house size within 500-ft radius.
View full Pasadena rules →Key Facts Comparison
| Fact | Altadena | Pasadena |
|---|---|---|
| Code Section | Altadena CSD 22.306.070.A.4 | - |
| GSA Formula | 0.25 × lot area + 1,000 sf | - |
| Maximum Cap | 9,000 sq ft | - |
| Excluded From GSA | Cellars + auto garages/carports | - |
| Standards | - | Vary by zoning district |
| Hillside | - | Includes all covered areas |
| House Size Cap | - | 35% above 500-ft median |
| Code | - | PMC Title 17 Zoning Code |
Highlighted rows indicate differences between cities.
Altadena FAQ
How big a house can I build on a 10,000-sq-ft Altadena lot?
Maximum GSA = 0.25 × 10,000 + 1,000 = 3,500 sq ft (excluding garage and cellar). The absolute cap is 9,000 sq ft on any lot.
Pasadena FAQ
What counts as lot coverage?
All impervious surfaces: buildings, garages, driveways, patios, and walkways. Permeable pavers may be partially excluded.
How do I calculate my lot coverage?
Divide total impervious surface area by total lot area. Check Pasadena zoning for your district’s maximum.
Compare other topics
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