San Pedro ADU 2026 | $160K-$320K, Garage Conversion, LADBS

A San Pedro ADU is usually one of two projects: a detached garage converted into a 400-700 square foot studio or one-bedroom (most common — most San Pedro lots have a single-car or two-car detached garage at the rear), or a new-build 600-1,200 square foot ADU in the back yard on a lot that has the room for it. The household is building it for an aging parent, an adult child, a long-term tenant, or as a permanent rental income source. San Pedro is City of LA, so LADBS handles permits, and standard California state ADU law applies — by-right approval, no discretionary review, no owner-occupancy required. NPLD has been designing in Los Angeles since 2016 and licensed as a CSLB general contractor since 2023, with over 200 LA builds completed including ADU work across the city. Our San Pedro ADUs run $160K-$320K over a 6-10 month timeline including design, permit, and construction. We pull through LADBS directly, we handle the asbestos and lead-paint protocols on older garage conversions, and we build the harbor-adjacent ADUs that work for real long-term occupancy.

What a San Pedro ADU Costs in 2026

Budget tiers depend on type and size. A garage conversion at 400-500 square feet runs $160K-$210K — that includes upgrading the foundation if needed (most pre-1960 garage slabs are not engineered for habitable use), framing for insulation and finished interior, full electrical and plumbing run from the main house, a small kitchen with a 24-inch range and a refrigerator, a full bathroom, a sleeping area, and a living space. A garage conversion at 500-700 square feet ($200K-$260K) opens up to a separate bedroom or larger living area. Detached new-build ADUs at 600-900 square feet run $220K-$300K. The top tier, 900-1,200 square feet detached with separate bedroom and full kitchen ($280K-$320K), includes upgrade-tier finishes. Site work — utility trenching to the main house, sewer connection or lateral upgrade, gas-line extension, electrical sub-panel — typically adds $14K-$35K depending on distance and existing utility capacity. LADBS permits and Title 24 documentation add $4K-$10K.

LADBS ADU Path and Garage Conversion Specifics

California state ADU law (Government Code 65852.2) applies. Standard ADUs up to 1,200 square feet are by-right on any single-family LA lot — no discretionary review, no neighbor consent required. Garage conversion ADUs (sometimes called Junior ADUs or JADUs depending on the configuration) follow similar rules but have specific code requirements: the structure must have been legally built and currently exist (we verify with LADBS records at intake), the foundation and structural framing must be brought up to current habitable-use standards, and the conversion has to include weather-tight envelope, code-compliant exits, smoke and CO detection, and a separate utility sub-panel. LADBS plan check on a garage conversion runs 4-8 weeks; new-build detached ADUs run 6-10 weeks. Vinegar Hill HPOZ rules apply only if the ADU is being built on a parcel inside the HPOZ — exterior design then needs Cultural Heritage Commission review. Most San Pedro ADU sites are outside the HPOZ. Setbacks: 4 feet from side and rear, 4 feet between ADU and main house. Height limit: 16 feet for detached new builds.

Garage Conversions — What Older San Pedro Garages Actually Need

Most San Pedro garages we convert were built between 1925 and 1965. The slab is often unreinforced concrete poured directly on grade, not engineered for habitable structures. We test slab thickness and condition at intake. If the slab is sound (4+ inches, no significant cracking), we can build over it with a moisture barrier and insulated subfloor system. If the slab is thin or cracking, we pour a new engineered slab inside the existing walls, which adds $8K-$16K. Walls are typically 2x4 stud framing with no insulation — we add R-15 or R-21 batt insulation, a vapor barrier, and finished interior drywall. The roof needs insulation added (R-30 or higher per current code) and often a new finished ceiling. Original garage doors get replaced with framed wall and code-compliant entry door. Windows get added to meet egress and natural light requirements. Plumbing and electrical run as new branches from the main house — we trench across the side yard or driveway, sleeve the lines properly, and patch hardscape after. Older garages frequently have asbestos in original siding, in concrete slab additives, or in the roof underlayment. We test before demo.

• Garage conversion 400-500 sqft (including foundation upgrades): $160K-$210K
• New engineered slab inside existing walls (if needed): $8K-$16K
• Detached new-build ADU 600-900 sqft: $220K-$300K
• Utility trenching to main house (water, sewer, gas, electrical): $14K-$35K
• Asbestos testing and abatement (older garage structures): $1.5K-$5K
• LADBS permits + Title 24 documentation: $4K-$10K

How We Build on San Pedro Lots

San Pedro lots typically run 5,000-7,500 square feet, with the main house at the front and a rear garage at the back of the lot (often accessed via a driveway down the side). For garage conversions, we work from the existing structure outward — demo, foundation work, framing, mechanical rough-in, finish. For detached new-build ADUs, we excavate and pour a new foundation, frame, and finish as a separate structure. Material deliveries (lumber, drywall, finishes) usually come down the driveway or through the side yard. Crane lifts are rarely needed on San Pedro lots given the typical scale and access. The build sequence on a garage conversion: testing and demo (week 1-2), foundation work and slab upgrades (week 3-5), framing and weather-tight envelope (week 6-9), mechanical, electrical, plumbing rough-in (week 9-12), drywall and exterior siding (week 13-16), interior finish and final mechanical (week 17-22), and LADBS final inspections plus certificate of occupancy (week 23-28). The household lives in the main house throughout the 6-10 month timeline.