Lot Coverage Limits: Altadena vs Santa Monica
How do lot coverage limits rules compare between Altadena, CA and Santa Monica, CA?
Altadena and Santa Monica 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 →Santa Monica, CA
Los Angeles County
Lot coverage in Santa Monica varies by zoning district. R1 district development standards are in Table 9.07.030. The zoning ordinance limits impervious coverage and includes landscape area requirements per SMMC Ch. 9.26.
View full Santa Monica rules →Key Facts Comparison
| Fact | Altadena | Santa Monica |
|---|---|---|
| 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 | - |
| R1 Standards | - | Table 9.07.030 |
| Landscape Area | - | SMMC Ch. 9.26 requirements |
| Impervious | - | Limited by district |
| Code | - | SMMC Article 9, Division 2 |
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.
Santa Monica 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 Santa Monica zoning for your district’s maximum.
Compare other topics
See how Altadena and Santa Monica compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool