What an ADU costs in Westchester (2026)
Westchester is part of the City of Los Angeles, right next to LAX. Here are typical numbers, the local rules, and your next step.
Typical ADU numbers in Westchester
- A 750 sq ft backyard ADU with a standard finish costs about $300,000 to build, all in: building, site work, city fees and design.
- Typical ADU rent: about $4,900 a month for 750 sq ft.
- Home value nearby: about $1,100 per sq ft (Westside and South Bay area).
Run the free ADU and new home cost calculator for Westchester
ADU permits and local rules in Westchester
Who runs permits
LA Department of Building and Safety (LADBS) handles building permits. LA City Planning handles zoning.
Pre-approved ADU plans
Yes. LA's ADU Standard Plan Program lists dozens of plans already checked by LADBS for building code. The city's own plan is free; the rest are bought from their designers. LADBS still checks your lot for zoning and foundation.
What can slow you down
- LAX airplane noise may call for sound-blocking windows and walls.
- Lots toward Playa del Rey may be in the Coastal Zone and need a coastal permit.
- If your lot has rent-stabilized units, LA tenant rules can add steps.
Sources: LADBS ADU Standard Plan Program page; LA City Planning ADU and HPOZ pages. State ADU law. General information, not legal advice. Updated October 2026.
Free lot check in Westchester
Send Hemisphere A&E your address. We look up your zoning and lot size, what fits (ADU, junior ADU, SB 9, new home, apartments, remodel or business space), red flags like fire zones or hillside rules, and a rough cost range. No cost, no pressure. Email info@hemisphereae.com or call (619) 762-7144.
More cost guides for Westchester
- What a new home costs in Westchester
- What a restaurant, shop or office build-out costs in Westchester
- What an apartment building costs in Westchester
Cost guides for more of LA County
- What an ADU costs in Alhambra
- What an ADU costs in Altadena
- What an ADU costs in Arcadia
- What an ADU costs in Beverly Hills
- What an ADU costs in Burbank
- What an ADU costs in Culver City
- What an ADU costs in Downey
- What an ADU costs in Eagle Rock
- What an ADU costs in El Segundo
- What an ADU costs in Glendale
- What an ADU costs in Hawthorne
- What an ADU costs in Highland Park
- What an ADU costs in Inglewood
- What an ADU costs in Lancaster
- What an ADU costs in Long Beach
- What an ADU costs in Malibu
- What an ADU costs in Manhattan Beach
- What an ADU costs in Mar Vista
- What an ADU costs in Pacific Palisades
- What an ADU costs in Pasadena
- What an ADU costs in Redondo Beach
- What an ADU costs in Santa Clarita
- What an ADU costs in Santa Monica
- What an ADU costs in Sherman Oaks
- What an ADU costs in South Pasadena
- What an ADU costs in Torrance
- What an ADU costs in Venice
- What an ADU costs in West Hollywood
- What an ADU costs in Whittier