Home Remodeling in
Edgewood, WA

Edgewood allows up to two ADUs per lot. Each can have up to 1,000 square feet of living space, or 80 percent of the main house's living space if that is larger, with a cap of 1,600 square feet. On a big house, that is room for a real second home rather than a studio.

A detached ADU can be as tall as the main house or 24 feet, whichever is greater. It needs a permanent foundation, and it has to meet the city's residential design standards, which are reviewed at the same time as the building permit.

The city updated these rules in June 2025.

The city's ADU submittal checklist, revised in April 2026, asks for a water availability letter signed by your water purveyor, showing the nearest hydrant and the fire flow available.

It also asks you to prove your sanitary connection. On septic, that means approval from the Tacoma-Pierce County Health Department with a stamped site plan showing the system's location and the number of bedrooms it allows. A community septic system or a sewer connection each has its own proof, and the connection permit has to be issued before the building permit.

A geotechnical report is added where there are soft soils, landslide or seismic hazards, and a school impact letter is due before the permit is issued. Starting the utility approvals early is the single best way to keep an Edgewood ADU on schedule.

If the ADU will be rented, Edgewood requires a city business license for the rental.

Units built in the past without approval can be brought into compliance using the same standards as a new ADU. Once approved, the owner records a title notice showing the unit was legally built. The city can also exempt the conversion of an existing legal building from setback, height and coverage standards.