Can I build a backyard home in Tacoma?
Since 2023, Washington law lets most city lots hold up to two more homes. Tacoma writes its own rules on top. Here’s what the code says, in plain English — and a free report on what may fit on your lot.
What Tacoma allows.
The headline standards. Open any card for the full wording and the code section.
ADUs per lot2 per lotFull wording
2 per lot
Max size1,000 sq ft of living areaFull wording
1,000 sq ft of living area
Max heightZone heightFull wording
Zone height; no separate ADU limit stated
Front setbackThe zone’s setbacksFull wording
Zone setbacks
Side setback5 ft (8 ft if the entrance faces the side line)Full wording
5 ft; 8 ft if the entrance faces the side lot line
Rear setback15 ft; 0 ft at an alleyFull wording
15 ft; 0 ft at an alley
Lot coverageThe zone’s standards; 10% of the lot stays usable yardFull wording
Zone standards; at least 10% of the lot must remain usable yard
ParkingNone requiredFull wording
None required; if provided, parking must be rear-accessed
Where a city figure reads stricter than the state floor (RCW 36.70A.681), the floor may control — the report flags it for your parcel.
Living there, selling it, plans, time and fees.
Each answer is the code’s own wording, with the section it comes from. “Not published yet” means the city hasn’t posted a figure — the report asks the city, not the internet.
Are backyard homes allowed?
Yes
Minimum lot size
Zone minimum applies
Do you have to live there?
Not stated on the tip sheet; prohibited as a requirement by state law inside the UGA
Can it be sold on its own?
Permitted by state law
Pre-approved plans
Yes — 4 base models, visitability-compliant, fitted to Home in Tacoma zoning, with site visits and pre-application support. Pre-approval is not pre-permitting.
How long the city takes
not published yet — ask the city
Impact fees
not published yet — ask the city
The code is half the answer. Your parcel is the other half.
Lines and easements
Where the lot lines really are, which setbacks apply on each side, and whether a utility or access easement takes the corner you had in mind.
Critical areas and slope
Steep slopes, wetlands and streams come with buffers that no citywide number shows. The report reads the county’s maps for your parcel.
Sewer, septic, water, trees
Whether sewer reaches the lot or it’s on septic, where the water service is, and which trees a city protects — the things that decide where a unit can actually go.
What Tacoma allows, what could fit on your lot, and a planning cost range. If something won’t fit, the report says so — and shows what might.
Where this page comes from.
Read from the Tacoma municipal code and the city’s own pages on September 15, 2026. The same table feeds the HousUp report, so the report and this page never disagree. Cities amend their codes; before you design anything, confirm the current wording with the city.
Other places in Pierce County.
Find out what your property could become.
Type your address. Within a few hours: what Tacoma allows, what could fit, and a planning cost range. Free, no obligation.