An ADU builder in Long Beach is a licensed contractor who designs and constructs accessory dwelling units — detached backyard units, garage conversions, attached additions, and junior ADUs (JADUs). Because an ADU is a complete second dwelling, the builder coordinates foundation, framing, plumbing, electrical, and HVAC work and pulls it through Long Beach's permit process and utility connections. Not every general contractor has built one, so the right builder is one with ADU-specific experience in California.
What ADU Builders Cost in Long Beach [20][21][22][23]
Based on our Long Beach cost data, expect the following ranges from local ADU builders. Quotes for the same scope typically vary 20-40% between contractors, so getting at least three bids is the single best way to control cost.
| New Detached ADU (all-in) | $215,000-$400,000 |
| Cost per Sq Ft | $310-$450 |
| Garage Conversion | $90,000-$180,000 |
| Prefab / Modular ADU (installed) | $90,000-$300,000 |
| City Permit & Plan Review | $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)) |
For a full line-item breakdown, see our Long Beach ADU cost guide. To confirm what you're allowed to build before you hire, review the Long Beach ADU rules (max detached size: 800 sq ft for a new detached ADU on a single-family lot (IB-PZ-001 Table 1, applying Gov. Code 66323(a)(2)(A)); ADU floor area is measured to the interior walls. On a multifamily lot a detached ADU has no size limit. Converting an existing detached garage or accessory building has no size limit either, but the only addition allowed is up to 150 sq ft for stairs or an entry. State law lets a city allow up to 1,200 sq ft (Gov. Code 66314(d)(5)), which the city's February 2025 summary did; if you want more than 800 sq ft on a single-family lot, ask the Planning Bureau (562-570-6194) before designing; owner-occupancy: Not required for an ADU (Gov. Code 66315). For a JADU the owner must live in the main house or the JADU only if the JADU shares a bathroom with the main house; a JADU with its own bathroom has no owner-occupancy requirement (IB-PZ-001; Gov. Code 66333(b) as amended by AB 1154, effective Jan 1, 2026). State JADU rules also call for a recorded deed restriction barring separate sale of the JADU (66333(c))).
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How to Vet an ADU Builder in Long Beach
- License: Confirm a current contractor's license in California and that it's in good standing. Ask for the license number and verify it with the state board.
- ADU-specific experience: Ask how many ADUs they've completed in or near Long Beach and request addresses or photos. ADU permitting and setbacks differ from a kitchen remodel.
- Portfolio & references: Get references from recent ADU clients and, if possible, visit a finished unit.
- Insurance: Verify general liability and workers' compensation coverage. Ask for a certificate of insurance.
- Written, detailed bid: Insist on an itemized, fixed-price or clearly-scoped bid — not a verbal estimate. It should state whether permits ($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), 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)), and 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))) are included.
- Permit handling: Confirm they manage Long Beach's permit process ("Ministerial building permit, no public hearing. 1) Read Planning Bulletin IB-PZ-001 and confirm your lot type and zone; in a historic district or on a landmark property a ministerial Certificate of Appropriateness is filed with the building permit application, and in the Coastal Zone an administrative Local Coastal Development Permit (no hearing) is required with it. 2) Submit in person at the Permit Center, 411 W. Ocean Blvd, 2nd floor (appointment or walk-in): the APP-001 permit application plus a complete plan set as one PDF on a USB drive; plan-check fees are due that day; online submittal is not offered. Simple projects may be reviewed over the counter, but not in a historic district, the Coastal Zone or with major structural engineering. 3) A planner and an engineer review concurrently; corrections are issued in writing and resubmitted to both; track status on the Plan Check Status page. 4) A ready-to-issue email, then the permit is issued in person and inspections are booked online at each phase. The application is not complete until every required plan, item and correction is supplied (IB-PZ-001, Application Requirements)", typically 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) and who is responsible if revisions are required.
- Payment schedule: Avoid large upfront payments. A reasonable schedule ties payments to completed milestones.
Questions to Ask Before You Hire
- How many ADUs have you built in Long Beach in the last two years?
- Is your bid fixed-price, and what would trigger a change order?
- Are permits, plan check, and utility connection fees included?
- What's a realistic timeline, including permit review (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) and construction?
- Who is my point of contact and how are delays communicated?
- What warranty do you provide on workmanship?
- Can you share three recent California ADU client references?
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How much do ADU builders charge in Long Beach?
ADU builders in Long Beach typically quote $215,000-$400,000 for a new detached unit, or about $310-$450 per square foot, including design, permitting, and construction. A garage conversion runs $90,000-$180,000 and a prefab/modular ADU averages $90,000-$300,000. Add city permit and plan-review 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) plus impact fees of 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)). Quotes for the same scope commonly vary 20-40% between builders, so collect at least three bids.
How do I find a good ADU builder in Long Beach?
Look for a licensed contractor with completed ADU projects in Long Beach specifically — ADUs involve local zoning, setback rules, and utility connections that general remodelers may not have handled. Verify the license, ask for an ADU-specific portfolio and references, confirm they carry liability and workers' comp insurance, and get a written fixed-price or detailed bid. Submit a request below and we'll forward it to local ADU builders serving Long Beach for free quotes.
Do ADU builders in Long Beach handle permits?
Most full-service ADU builders manage the permit process for you. In Long Beach the approval process is "Ministerial building permit, no public hearing. 1) Read Planning Bulletin IB-PZ-001 and confirm your lot type and zone; in a historic district or on a landmark property a ministerial Certificate of Appropriateness is filed with the building permit application, and in the Coastal Zone an administrative Local Coastal Development Permit (no hearing) is required with it. 2) Submit in person at the Permit Center, 411 W. Ocean Blvd, 2nd floor (appointment or walk-in): the APP-001 permit application plus a complete plan set as one PDF on a USB drive; plan-check fees are due that day; online submittal is not offered. Simple projects may be reviewed over the counter, but not in a historic district, the Coastal Zone or with major structural engineering. 3) A planner and an engineer review concurrently; corrections are issued in writing and resubmitted to both; track status on the Plan Check Status page. 4) A ready-to-issue email, then the permit is issued in person and inspections are booked online at each phase. The application is not complete until every required plan, item and correction is supplied (IB-PZ-001, Application Requirements)" with a typical review timeline of 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. Confirm in writing whether permit fees, 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)), and impact fees are included in the bid or billed separately.
How long does it take to build an ADU in Long Beach?
Plan for the permit review (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 in Long Beach) plus construction. Most detached ADUs take 4-8 months of construction after permits are issued; garage conversions and prefab units are often faster. Ask each builder for a realistic schedule and what could delay it.
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