Can I build a backyard home in University Place?
Since 2023, Washington law lets most city lots hold up to two more homes. University Place 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 University Place allows.
The headline standards. Tap any one for the full wording and the code section.
ADUs per lot2 per lot with a detached single-family houseFull wording
2 per lot with a detached single-family house; 1 detached ADU on a lot below the zone minimum lot size; 1 ADU with a two-unit middle-housing building that meets the minimum lot size (UPMC 19.70.010(B)(1)).
Max size1,000 sq ftFull wording
1,000 sq ft (UPMC 19.70.010(B)(3)); the Director may allow more when the ADU occupies a single floor of an existing multistory structure. No exclusions stated.
Max height24 ft to the ridgeFull wording
24 ft to the ridge (10 ft to the top wall plate) where a detached ADU sits in a required side or rear yard (UPMC 19.70.010(B)(4)(d)); the R1/R2 zone limit is 35 ft (UPMC 19.45.100).
Front setbackZone front setback: 20 ftFull wording
Zone front setback: 20 ft (25 ft to a garage/carport) in R1 and R2 (UPMC 19.45.100); UPMC 19.70.010 gives no front-yard reduction.
Side setback5 ft for a detached ADU (the zone: 8 ft)Full wording
5 ft for a detached ADU, eaves at least 3 ft from any property line (UPMC 19.70.010(B)(4)(b)-(c)); only one detached ADU per lot may use the reduced setbacks; the R1/R2 zone side setback is 8 ft (UPMC 19.45.100).
Rear setback5 ft for a detached ADUFull wording
5 ft for a detached ADU (UPMC 19.70.010(B)(4)(b)); may sit at a property line abutting a public alley the city does not routinely plow (UPMC 19.70.010(B)(4)(g)); at least 5 ft from the primary structure; R1/R2 zone rear setback is 30 ft (UPMC 19.45.100).
Lot coverage50% in R1 and R2Full wording
50% in R1 and R2 (UPMC 19.45.100).
Parking1 per ADU on lots to 6,000 sq ft, 2 on larger; none near major transitFull wording
0 within 1/2 mile walking distance of a major transit stop; otherwise 1 space per ADU on lots of 6,000 sq ft or less and 2 spaces per ADU on lots over 6,000 sq ft (UPMC 19.70.010(B)(5)).
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 — attached, detached, or within a detached accessory structure (carriage unit) on a lot of record with a detached single-family house (UPMC 19.70.010(B)(1)-(2)); the section does not list zones (R1/R2 standards used below).
Minimum lot size
None for one ADU; a lot below the zone minimum is limited to one detached ADU (UPMC 19.70.010(B)(1); zone minimums in UPMC 19.45.100).
Do you have to live there?
No — UPMC 19.70.010 contains no owner-occupancy requirement.
Can it be sold on its own?
Not addressed in UPMC 19.70.010; RCW 36.70A.681 floor applies. The city's Middle Housing page says an ADU can be separated through a unit lot subdivision (UPMC 21.75).
Pre-approved plans
None found; the city publishes an ADU Development & Design Guidebook (https://www.cityofup.com/DocumentCenter/View/5505).
How long the city takes
Not published
Impact fees
Not found; RCW 36.70A.681 caps ADU impact fees at 50% of the principal unit's.
Plans University Place has already approved.
A pre-approved plan skips the design review: University Place has already checked the drawings, so the permit review is about your lot.
Loading the plans…
Pictures are the official pages’ own. A pre-approved plan is not a permit: the city still reviews your site.
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 University Place 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 University Place municipal code and the city’s own pages on November 5, 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.
2 sources, read November 5, 2026
Find out what your property could become.
Type your address. Within a few hours: what University Place allows, what could fit, and a planning cost range. Free, no obligation.