Cost to build accessory dwelling unit — Huntington Beach, CA

Last updated: September 24, 2026

What affects the price

Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.

About this service

Building an ADU involves costs for permits, site prep, foundation, framing, plumbing, and electrical work. Prices fluctuate based on whether you choose a custom design or a pre-planned layout, as well as the complexity of connecting to existing city utilities. Exact pricing confirmed free on the call.

Frequently asked in Huntington Beach

Also serving nearby: Westminster · Costa Mesa · Garden Grove · Santa Ana · Orange

All cities in California →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Huntington Beach — population 192,129; about 7,120 residents per square mile across 27.0 sq mi. ZIP codes covered include 92605, 92615, 92646, 92647, 92648, 92649.

Neighborhoods served in Huntington Beach: Downtown Huntington Beach, Bolsa Chica, Seacliff, Old Towne Huntington Beach — and every surrounding area.