ADU cost
What an ADU actually costs: permit fees, impact fee thresholds, real project budgets and the difference between a declared valuation and a quote.
Money, in the two places it actually goes: the fees a city charges to permit the unit, and what the build itself comes to. These posts cover real project budgets with the figures attached, the thresholds that change what you owe (750 square feet for impact fees, 500 for school fees), and the fee changes moving through the legislature.
Start here: What an ADU costs in Los Angeles
13 posts on adu cost
This LA ADU Cost $89,430. Being Your Own Architect Is Why.
When a Highland Park architect built a backyard ADU for his in-laws, the line items totaled $89,430. That number is real, but it hides the two salaries he never paid: his own, as both architect and general contractor.
September 16, 2026
California Will Charge ADU Fees Only on the Space Over 750 Feet
California already waives impact fees on ADUs of 750 square feet or less. SB 1117, which Governor Newsom signed on September 29, 2026, charges the fees on a larger unit only for the square footage above 750, not the whole thing, on lots with up to two ADUs, starting January 1, 2027.
September 9, 2026
This Couple Built Their Own Portland ADU. The Waiver Costs 10 Years.
An architect and a construction engineer built a 624-square-foot home in their Portland backyard for $221,580. Oregon let them build by right; Portland waived the fees, if they skip short-term rentals for 10 years.
August 29, 2026
A Los Feliz Studio Tops the Garage for $220,722. Watch the Stairs.
An LA family stacked a 350-square-foot studio on top of their detached garage in Los Feliz for $220,722. The build reads simple until the staircase, the fire-rated floor, and the noise from below each ask for a say.
August 28, 2026
Washington Caps ADU Impact Fees at Half, Scraps Transit Parking
Washington's HB 1337 bars a city from charging an ADU more than half the impact fees a main house pays, and forbids off-street parking rules within a half-mile of major transit. Here is what it saves you.
August 13, 2026
Portland Waived SDCs for New Housing. Your ADU Didn't Make the List.
Portland waived development fees on most new housing through 2028, about nineteen thousand dollars a unit on average. ADUs are cut out, and still run on an older waiver that swaps those fees for a 10-year ban on short-term rentals.
August 5, 2026
Your LA ADU Skips Impact Fees at 750 Feet. School Fees Start at 500.
On August 11, Los Angeles Unified raises its school developer fee to $5.38 a square foot. A state law from January already decides whether your ADU owes a cent of it, and the answer turns on 500 square feet.
August 1, 2026
The $349,000 ADU Value Gap Is Real. It Is Not Your Payout.
California homes with an ADU appraised at a median $1,064,000 in 2023, versus $715,000 without one. Before you count that $349,000 as your payout, read what the FHFA data actually measured, and what it did not.
July 19, 2026
The LADBS Plan Is Free. The 750-Square-Foot ADU Is Not.
Los Angeles gives away pre-approved ADU plans, and its YOU-ADU design is free. The plan is the cheap part. A 750-square-foot build still runs past $250,000, and your tape measure decides whether fees pile on.
July 9, 2026
A-du's Permit Fee Calculator: What Each Line Item Really Means
A-du's permit fee calculator prices a 750-square-foot LA ADU at $9,228.96 across 18 line items and an 800-square-foot NYC ADU at $1,591.25 across two, each citing its own code section.
July 1, 2026
Signed: SB 1117 Cuts ADU Impact Fees Over 750 Square Feet in 2027
California's SB 1117, signed September 29, 2026, sets a new impact fee formula: starting January 1, 2027, ADUs on lots with up to two ADUs are charged only on square footage above the existing 750-square-foot exemption line.
June 9, 2026
Detached, Attached, or JADU: Cost, Timeline, and Rental Yield Compared
California homeowners choosing between a detached ADU, attached ADU, or JADU face real differences in build cost, permit timeline, and rental yield. Here is how the three types compare under state statute.
June 8, 2026
LA's GPMS Rose to 10% on June 9. ADU Building Permits Still Pay 7%.
On June 9, 2026, Ordinance 188,899 raised the City of Los Angeles General Plan Maintenance Surcharge from 7% to 10% on City Planning fees. The surcharge LADBS adds to ADU building permits is set in a different code section and is still 7%.
June 6, 2026