ADU rules in California, Oregon, Washington, Texas and Florida

ADU rules are mostly local. But some states now set a floor that every city must meet, and others leave cities almost total freedom. Here is where five of the biggest ADU markets stand. Laws change often, so treat this as a starting point and confirm with your city.

California

California has the most detailed state ADU law in the country, and the results show it. Between 2016 and 2024 the number of ADUs permitted each year in the state grew from 1,336 to 30,354, and in 2024 ADUs were more than 26.6 percent of all homes permitted statewide.

Key rules from the state's ADU handbook:

• Cities must approve or deny a complete application within 60 days, or it is deemed approved.
• Cities cannot require the owner to live on the property for an ADU. A JADU that shares a bathroom with the house does require the owner to live there.
• Cities must allow at least 850 square feet, or 1,000 square feet for more than one bedroom, and cannot use lot coverage or similar rules to block an 800 square foot unit with four-foot side and rear setbacks.
• No impact fees on ADUs of 750 square feet or less.
• HOAs cannot prohibit or unreasonably restrict ADUs.

The state housing department keeps the handbook and an ADU portal where you can ask for help or report a city that is not following the law.

Oregon

Oregon law requires cities over 2,500 people and counties over 15,000 to allow at least one ADU for each detached single-family home in areas inside the urban growth boundary zoned for single-family homes. The state's definition covers interior, attached and detached units.

Cities can apply reasonable siting and design rules, but the law says those rules cannot include owner-occupancy requirements or requirements to build additional off-street parking. Cities can still require owner occupancy or parking for vacation rentals. The state land use agency's implementation guidance encourages cities to consider allowing two ADUs.

Portland waives system development charges for new ADUs whose owners sign a 10-year covenant against short-term rentals.

Washington

Washington's HB 1337, passed in 2023, applies inside urban growth areas. According to the state Commerce Department, cities and counties must:

• Allow two ADUs per lot, attached, detached or one of each.
• Allow an ADU of at least 1,000 square feet.
• Not require the owner to live on the property, except where the unit is a short-term rental.
• Not charge more than 50 percent of the impact fees charged for the main house.
• Not require off-street parking within a half mile of a major transit stop.

The regional checklist adds a 24 foot minimum height allowance, limits on design review and a ban on requiring street improvements. The bill report explains that the rules take effect six months after each city's next periodic comprehensive plan update, so timing varies by city.

Texas

Texas has no statewide ADU law. A 2025 bill, SB 673, passed the state Senate, but the legislative record shows it did not pass the House. ADU rules come from each city.

Austin is a good example of how detailed local rules can be. Its ADU page says ADUs are allowed in certain single-family zones on lots of at least 5,750 square feet, each new unit needs its own address, deed restrictions may apply, and ADUs built after October 1, 2015 cannot be short-term rentals for more than 30 days a year.

Florida

Florida's statute allows, but does not require, cities and counties to adopt an ordinance allowing ADUs in single-family zones. Under the statute, a permit application for an ADU must include an affidavit that the unit will be rented at an affordable rate to an extremely-low-, very-low-, low- or moderate-income person. "Affordable" means rent and utilities do not exceed 30 percent of the relevant income level. Local ordinances vary widely, so check your county or city code.

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