Garage Conversions: Castaic vs Santa Monica
How do garage conversions rules compare between Castaic, CA and Santa Monica, CA?
Castaic and Santa Monica have similar restriction levels.
Castaic, CA
Los Angeles County
Garage conversions to ADUs in unincorporated Castaic are governed by LA County Code Title 22 §22.140.640 and California Government Code §65852.2. No replacement parking is required when an existing garage is converted, and the existing garage's setbacks are grandfathered. Properties in Very High Fire Hazard Severity Zones also trigger Chapter 7A wildland-urban interface standards.
View full Castaic rules →Santa Monica, CA
Los Angeles County
Santa Monica allows garage conversions to ADUs under SMMC §9.31.025. Replaced parking spaces do not need to be provided. Conversions of existing structures are exempt from setback requirements.
View full Santa Monica rules →Key Facts Comparison
| Fact | Castaic | Santa Monica |
|---|---|---|
| Governing Code | LA County Code §22.140.640 | - |
| Replacement Parking | Not required | Not required |
| Existing Setbacks | Grandfathered | - |
| Fire-Zone Construction | Chapter 7A in WUI areas | - |
| Permit Required | Yes — LA County building | - |
| Code Section | - | SMMC §9.31.025 |
| Setback Exemption | - | Existing structures exempt |
| JADU in Garage | - | Allowed (attached garage) |
| Transit Parking Exempt | - | Within 1/2 mile of transit |
Highlighted rows indicate differences between cities.
Castaic FAQ
Do I need to add parking if I convert my Castaic garage to an ADU?
No. Cal. Gov Code §65852.2 and LA County Code §22.140.640 prohibit the county from requiring replacement parking when a garage is converted to an ADU.
Are fire-resistant materials required for a Castaic garage conversion?
Yes, where the property is in a Very High Fire Hazard Severity Zone. Chapter 7A of the California Building Code requires ignition-resistant siding, eaves, vents, windows, and roofing in WUI areas.
Who issues a Castaic garage conversion permit?
LA County Public Works (Building & Safety) issues the building permit; LA County Regional Planning handles the ministerial ADU planning review under §22.140.640.
Santa Monica FAQ
Can I convert my garage into living space in Santa Monica?
Santa Monica allows garage conversions to ADUs under SMMC §9.31.025. Replaced parking spaces do not need to be provided. Conversions of existing structures are exempt from setback requirements.
What permits do I need for a garage conversion in Santa Monica?
Code Section: SMMC §9.31.025. Replacement Parking: Not required. Setback Exemption: Existing structures exempt. JADU in Garage: Allowed (attached garage).
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