Before You Build in Castaic, CA: Permit & Rule Checklist (2026)
Everything you need to know before starting a home improvement project
Building a fence, installing a pool, or adding a shed? Each project has its own set of local permits and rules in Castaic. This guide consolidates fence, pool, ADU, shed, fire pit, and landscaping regulations into one checklist so you know what to expect before you start.
Quick Permit Checklist
At-a-glance overview of permit categories in Castaic. Click any card for details.
Fences & Walls
Height limits, materials, permits, and shared fence rules.
No specific fences & walls rules found for Castaic. Check with your local building department for current requirements.
Swimming Pools
Pool permits, safety fencing, and drainage requirements.
No specific swimming pools rules found for Castaic. Check with your local building department for current requirements.
ADUs & Granny Flats
Some RestrictionsAccessory dwelling unit rules and garage conversion permits.
Garage Conversions
Some RestrictionsGarage 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.
ADU Rules
Some RestrictionsCastaic is an unincorporated CDP in Los Angeles County governed by LA County Code Title 22 §22.140.640 (Accessory Dwelling Units and Junior Accessory Dwelling Units), most recently amended April 2024. Single-family lots may add one ADU plus one JADU; multifamily lots may add up to two detached new-construction ADUs plus conversion ADUs created in non-livable existing space.
Sheds & Outbuildings
Shed permits, setback limits, and outbuilding size rules.
No specific sheds & outbuildings rules found for Castaic. Check with your local building department for current requirements.
Fire Pits & Outdoor Structures
Fire pit placement, outdoor burning restrictions, and permits.
No specific fire pits & outdoor structures rules found for Castaic. Check with your local building department for current requirements.
Landscaping & Tree Removal
Tree removal permits, heritage tree protections, and water rules.
No specific landscaping & tree removal rules found for Castaic. Check with your local building department for current requirements.
General Permit Tips
When do you typically need a permit?
Most cities require permits for structural work, including fences over a certain height, pools, ADUs, and sheds above a size threshold. Even projects that seem minor can trigger permit requirements, so it is always best to check first.
How to apply for a building permit
Visit your local building department or their website. Most jurisdictions accept online applications. You will typically need a site plan, project description, and may need contractor information. Processing times vary from same-day for simple projects to several weeks for larger builds.
Common permit violations to avoid
Building without a permit, exceeding approved dimensions, and ignoring setback requirements are the most common violations. Penalties can include fines, required removal of the structure, and complications when selling your home.
Permit Guides for Nearby Cities
Looking for rules beyond permits? View all ordinances we track for Castaic.