Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Huntington Beach ADU cost →Building an ADU in Huntington Beach costs between $180,000-$420,000 for new construction, with per-square-foot costs averaging $315-$525. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $90,000-$150,000, while prefab/modular ADUs fall in between at $120,000-$300,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | Building permits roughly $2,000-$10,000 plus other city fees of $3,000-$11,000 depending on project size (secondary-source estimates); a 6% automation fee is added — confirm with the HB Permit Center fee schedule |
| Impact Fees | Waived for ADUs under 750 sq ft (state law); otherwise development impact fees are payable at permit issuance — confirm amounts with Community Development |
| Site Prep & Foundation | $10,000 – $35,000 |
| Framing & Structure | $15,000 – $45,000 |
| Plumbing | $8,000 – $20,000 |
| Electrical | $5,000 – $15,000 |
| HVAC | $3,000 – $8,000 |
| Interior Finishes | $15,000 – $40,000 |
Quotes for the same ADU commonly vary 20–40% between builders. Get up to 3 free quotes from ADU builders serving Huntington Beach — no obligation.
Get Huntington Beach builder quotes →Permit fees in Huntington Beach are Building permits roughly $2,000-$10,000 plus other city fees of $3,000-$11,000 depending on project size (secondary-source estimates); a 6% automation fee is added — confirm with the HB Permit Center fee schedule. The review timeline is Initial plan review approximately 20 days, resubmittals 5-10 days; state law caps total ADU review at 60 days with deemed approval (SB 543, 2026), with plan check: Plan check via Permit Center; ~20-day first review, 5-10 days for rechecks — confirm current turnaround with the city. Impact fees are Waived for ADUs under 750 sq ft (state law); otherwise development impact fees are payable at permit issuance — confirm amounts with Community Development. Pre-approved plans: Yes — free pre-approved 1-story, 490 sq ft detached ADU prototype in three styles (California Ranch, Bungalow, Spanish Colonial) under AB 1332; modifications to the pre-approved plan are not allowed.
| 1-Bedroom Rent | $2,400-$2,700/month |
| 2-Bedroom Rent | $3,000-$3,300/month |
| Annual Rental Income (est.) | $30,600/year |
| Payback Period (est.) | 9.8 years |
| Short-Term Rental | Effectively no for new ADUs — HB permits STRs under Chapter 5.120 (effective Feb 19, 2021), but ADUs/JADUs qualify only if legally established before that date |
| Overall ROI Estimate | 5-8% annual return |
A typical ADU in Huntington Beach generates approximately $30,600 per year in rental income based on average 1-bedroom rents. At an average construction cost of $300,000, the estimated payback period is 9.8 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Huntington Beach and varies by market (often less than build cost).
1. Garage conversions save 40-60% vs new construction since the shell already exists. Average cost in Huntington Beach: $90,000-$150,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $120,000-$300,000.
3. Pre-approved plans — available in Huntington Beach, which can save $3,000-$10,000 in design costs and 2-3 months in review time.
4. State grants — California's CalHFA ADU grant (up to $40K) is currently paused; check calhfa.ca.gov/adu for status and your state for active programs.
5. Get multiple bids — ADU contractor pricing varies 20-40% for the same project. We recommend getting at least 3 quotes.
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