Before You Build in Altadena, CA: Permit & Rule Checklist (2026)

Pool barriers in Altadena must be at least 60 inches tall, with no more than 2 inches gap below, and gates self-closing and self-latching with latch at least 60 inches above ground (LA County Building Code Manual 3109.2).

Altadena CSD caps front-yard fences at 42 inches within 10 feet of the right-of-way (with open/non-view-obscuring design ≥80% transparency required for taller fences), and 6 feet beyond 10 feet from the right-of-way.

Every new or remodeled residential pool in Altadena requires a 60-inch barrier with self-closing/self-latching gates plus at least 2 additional safety features under the California Pool Safety Act.

All swimming pools, spas, and hot tubs in Altadena require a building permit from LA County Building & Safety under Title 26 (Building Code) plus a plumbing permit and electrical permit for equipment.

Altadena 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 in non-livable existing space.

Garage conversions to ADUs in unincorporated Altadena 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 existing setbacks are grandfathered. Properties in Very High Fire Hazard Severity Zones also trigger Chapter 7A wildland-urban interface standards.

Carports in Altadena are accessory structures regulated under Altadena CSD 22.306.070 and LA County Code 22.110.040. They count toward the lot-coverage formula and the 2-space minimum parking requirement.

Sheds 120 sq ft or smaller and ≤12 ft tall typically don't need a building permit in Altadena, but they still must comply with Altadena CSD setbacks. Anything larger needs a permit.

Altadena sits in or adjacent to Very High Fire Hazard Severity Zones (Eaton Canyon, foothills). LA County Fire Code Title 32 restricts open flames and recreational fires; STRs in VHFHSZ must post a no-flame notice (LA County Code 7.96.060.O).

Open outdoor burning of vegetation is generally prohibited in unincorporated LA County. SCAQMD Rule 444 governs agricultural and rangeland burning; permits required from LA County Fire.

Outdoor watering in Altadena (served by Lincoln Avenue Water Co., Las Flores Water Co., Rubio Cañon, and Kinneloa Irrigation District) is limited to 2 days per week assigned by address — typically Mon/Thu odd, Tue/Fri even — with 10-minute-per-zone caps.

Oak trees (genus Quercus) with a trunk circumference of 25 inches or more (8-inch diameter at 4.5 ft above grade) are protected — removal, damage, or encroachment into the protected zone requires an Oak Tree Permit under LA County Code Chapter 22.174.

Trimming protected oak trees (≥8 in DBH) requires an Oak Tree Permit if the work enters the protected zone or removes >25% of crown. Street trees in the public right-of-way are maintained by LA County Public Works.