Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Torrance ADU cost →Building an ADU in Torrance costs between $200,000-$380,000 for new construction, with per-square-foot costs averaging $250-$400. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $70,000-$160,000, while prefab/modular ADUs fall in between at $120,000-$280,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | Fee assessed at building-permit application covering plan review, permit processing, and development impact mitigation — confirm amounts with Community Development, (310) 618-5990 |
| Impact Fees | Waived under 750 sq ft per state law; charged proportionately above — confirm with the Community Development Department |
| 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 Torrance — no obligation.
Get Torrance builder quotes →Permit fees in Torrance are Fee assessed at building-permit application covering plan review, permit processing, and development impact mitigation — confirm amounts with Community Development, (310) 618-5990. The review timeline is 60 days from complete application per state law (SB 543 deemed-approval applies from 2026), with plan check: Plan review with a full corrections list returned within the 60-day statutory window; City of Torrance Design Guidelines apply (Torrance Tract Design Guidelines in the historic overlay). Impact fees are Waived under 750 sq ft per state law; charged proportionately above — confirm with the Community Development Department. Pre-approved plans: Yes — City of Torrance Pre-Approved ADU Program through the Building & Safety Division.
| 1-Bedroom Rent | $2,100-$2,400/month |
| 2-Bedroom Rent | $2,600-$3,100/month |
| Annual Rental Income (est.) | $27,000/year |
| Payback Period (est.) | 10.7 years |
| Short-Term Rental | No — ADUs and JADUs may not be rented for less than 30 days |
| Overall ROI Estimate | 5-8% annual return (gross rental yield estimate) |
A typical ADU in Torrance generates approximately $27,000 per year in rental income based on average 1-bedroom rents. At an average construction cost of $290,000, the estimated payback period is 10.7 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Torrance 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 Torrance: $70,000-$160,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $120,000-$280,000.
3. Pre-approved plans — available in Torrance, 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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