Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Long Beach ADU cost →Building an ADU in Long Beach costs between $215,000-$400,000 for new construction, with per-square-foot costs averaging $310-$450. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $90,000-$180,000, while prefab/modular ADUs fall in between at $90,000-$300,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | $5,500-$6,500 in city plan-check and permit fees for a 750-800 sq ft new ADU (derived from the Building Permit & Plan Check Fees effective 5/20/2026 and IB-077's $175.92 per sq ft R-3 valuation): combination building permit at 150% of the valuation-based permit fee ($1,264 for the first $100,000 of valuation plus $6 per $1,000 above, min $164), combination plan check at 85% of the permit fee (min $154), zoning plan check at 0.5% of valuation (min $310), NPDES at $2 per $1,000 plus 75% for plan check, a $115 processing fee per application, and 6% Technology and 6% General Plan surcharges on all applicable fees; expedited plan check costs 2x. The city's own guide: budget about 2% of construction cost for plan check, permits and inspections. Impact, school and sewer fees are extra |
| Impact Fees | None for an ADU of 750 sq ft or less of interior livable space or a JADU of 500 sq ft or less (Gov. Code 66311.5(c), SB 543). Above 750 sq ft the city's Development Impact Fee schedule (effective 10/1/2025) charges ADU rates of $241.74 Fire, $1,781.39 Parks and Recreation and $342.86 Police per unit, $2,366 in total; the Transportation Improvement Fee lists $236.25 for an accessory unit up to 220 sq ft and $663.75 up to 640 sq ft (ask the Permit Center for larger units). Long Beach Utilities' sewer capacity fee is $144.34 (rate effective 10/1/2025) and may apply to a new detached unit but not to a conversion of existing space (66311.5(d)); LBUSD school developer fees apply to an ADU of 500 sq ft or more (rate at lbschools.net/developerfees), none below 500 sq ft (66311.5(c)(3)) |
| 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. We pass your request to up to 5 local builders serving Long Beach, where we have them — free, no obligation.
Get Long Beach builder quotes →Permit fees in Long Beach are $5,500-$6,500 in city plan-check and permit fees for a 750-800 sq ft new ADU (derived from the Building Permit & Plan Check Fees effective 5/20/2026 and IB-077's $175.92 per sq ft R-3 valuation): combination building permit at 150% of the valuation-based permit fee ($1,264 for the first $100,000 of valuation plus $6 per $1,000 above, min $164), combination plan check at 85% of the permit fee (min $154), zoning plan check at 0.5% of valuation (min $310), NPDES at $2 per $1,000 plus 75% for plan check, a $115 processing fee per application, and 6% Technology and 6% General Plan surcharges on all applicable fees; expedited plan check costs 2x. The city's own guide: budget about 2% of construction cost for plan check, permits and inspections. Impact, school and sewer fees are extra. The review timeline is up to 60 days by state law; the city publishes no typical review time. A completeness determination is due within 15 business days and approval or denial within 60 days of a complete application, or the ADU is deemed approved (Gov. Code 66317, SB 543); pre-approved-plan ADUs can be approved over the counter and permitted the same day, with plan check: Combination plan check (building, electrical, plumbing and mechanical in one review) at 85% of the building permit fee, min $154; expedited review at 2x halves the turnaround; each recheck is 50% of the permit fee, min $286. Bring the APP-001 application, a FORM-028 plot plan, the full plan set as a single PDF, a site-specific Title 24 energy report (CF-1R) and, for new construction, one Low Impact Development stormwater measure on the plans (IB-068). Fire sprinklers are required only if the main house has them (Gov. Code 66314(d)(12)); a new detached ADU generally needs rooftop solar under the California Energy Code, permitted separately; a PAADU submittal must show 200 A minimum electric service (IB-068). Impact fees are None for an ADU of 750 sq ft or less of interior livable space or a JADU of 500 sq ft or less (Gov. Code 66311.5(c), SB 543). Above 750 sq ft the city's Development Impact Fee schedule (effective 10/1/2025) charges ADU rates of $241.74 Fire, $1,781.39 Parks and Recreation and $342.86 Police per unit, $2,366 in total; the Transportation Improvement Fee lists $236.25 for an accessory unit up to 220 sq ft and $663.75 up to 640 sq ft (ask the Permit Center for larger units). Long Beach Utilities' sewer capacity fee is $144.34 (rate effective 10/1/2025) and may apply to a new detached unit but not to a conversion of existing space (66311.5(d)); LBUSD school developer fees apply to an ADU of 500 sq ft or more (rate at lbschools.net/developerfees), none below 500 sq ft (66311.5(c)(3)). Pre-approved plans: Yes, but paused. The Pre-Approved ADU (PAADU) Program (Building & Safety IB-068, rev. 1/27/2025) offers single-story, detached, all-electric standard plans under 1,200 sq ft for new construction only; a site-specific submittal is reviewed over the counter and the permit can issue the same day. The plan approvals previously listed (an 800 sq ft single-story design in four foundation and patio variants) expired December 31, 2025, and the city says the program is currently undergoing changes with no plan list published as of June 2026; check the PAADU page or email PlanCheck.Counter@longbeach.gov before choosing a plan.
| 1-Bedroom Rent | $1,800-$2,400/month |
| 2-Bedroom Rent | $2,400-$3,100/month |
| Annual Rental Income (est.) | $25,200/year |
| Payback Period (est.) | 12.2 years |
| Short-Term Rental | No. |
| Overall ROI Estimate | 6-10% gross rental yield (before taxes, vacancy and financing) |
A typical ADU in Long Beach generates approximately $25,200 per year in rental income based on average 1-bedroom rents. At an average construction cost of $307,500, the estimated payback period is 12.2 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Long 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 Long Beach: $90,000-$180,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $90,000-$300,000.
3. Pre-approved plans — available in Long Beach, which can save $3,000-$10,000 in design costs and 2-3 months in review time. See which cities offer pre-approved ADU plans.
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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