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 May Charge ADU Fees Only on the Space Over 750 Feet
California already waives impact fees on ADUs under 750 square feet. A bill now on Governor Newsom's desk, SB 1117, would charge the fees on a larger unit only for the square footage above 750, not the whole thing.
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, worth tens of thousands a unit. 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 $4,899.83 across 17 line items and an 800 square foot NYC ADU at $1,591.25 across two, each citing its own code section.
July 1, 2026
SB 1117 Would Cut ADU Impact Fees for Units Over 750 Square Feet
California's SB 1117, introduced in February 2026, proposes a new impact fee formula that charges ADU builders 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
Los Angeles ADU Permits: GPMS Fee Surcharge Rising to 10% on June 9
The City of Los Angeles raises its General Plan Maintenance Surcharge from 7% to 10% on June 9, 2026, affecting every LADBS building permit including ADU plan checks, permit issuance, and inspection fees.
June 6, 2026