Tacoma ADU rules
✓ Verified against code · August 19, 2026
Current rules under TMC 13.06.080.A, under the Home in Tacoma Phase 2 zoning (UR-1/UR-2/UR-3), adopted by Home in Tacoma Phase 2 (adopted Nov 19, 2024), in effect since February 1, 2025. Home in Tacoma Phase 2, effective February 1, 2025, replaced Tacoma's single-family zoning with Urban Residential zones and folded detached ADUs into the 'Backyard Building' housing type. But Tacoma's ADU fundamentals — no parking, no owner-occupancy, DADUs citywide — date to its 2019 reform (Ord 28576), years ahead of the state mandate. Widely-read national guides still describe pre-2019 rules under fresh-looking date stamps.
Common questions, answered from the code
Do I need off-street parking to build an ADU in Tacoma?
No — zero parking is required for ADUs anywhere in Tacoma, and it has been that way since 2019. Beware: as of mid-2026, the #1 search result for this question was a page stamped 'Updated June 2026' still claiming a space is typically required. It isn't.
TMC 13.06.080.A.4.d · Permalink
How many ADUs can I build on a Tacoma lot?
Two, on any legally established lot regardless of size, in addition to the primary dwelling — attached, detached, or one of each.
TMC 13.06.080.A.4.a · Permalink
Do I have to live on the property?
No — Tacoma removed owner-occupancy in 2019. The exception is short-term rentals: to run an ADU or the main house as an STR, the owner must occupy one of the dwellings.
TMC 13.06.080.A.4.g · Permalink
How tall can a Tacoma DADU be?
Zone limits apply rather than an ADU-specific cap: 35 ft in UR zones, but 25 ft within the rear 25 feet of a UR-1 lot, which is where most backyard DADUs sit. The old 18-ft DADU cap is gone.
TMC 13.06.020.F.1 · Permalink
How long does a Tacoma ADU permit take?
It's a building permit with no discretionary review; the city's published service goal for residential new-building permits is 8 weeks.
tacomapermits.org level-of-service page · Permalink
The rules at a glance
| ADUs allowed per lot | Two ADUs per residential lot, on any legally established lot regardless of size or width, in any zone permitting residential use — attached, detached, or a mix. All dwellings must be in single ownership.TMC 13.06.080.A.4.a, A.5.a |
| Maximum size | 1,000 sq ft of habitable living area, excluding garage and other non-living areas. An ADU occupying a single floor of an existing building may exceed this to use the whole floor efficiently.TMC 13.06.080.A.5.b |
| Detached ADU height | No ADU-specific cap — zone and housing-type limits apply: 35 ft in UR zones, but 25 ft within the rear 25 ft of UR-1 lots (where most DADUs sit). The old 18-ft DADU cap was repealed.TMC 13.06.080.A.5.c; 13.06.020.F.1 |
| Detached ADU setbacks | Side: 5 ft (8 ft where a main entrance faces the side lot line). Rear: 15 ft in UR-1, 10 ft in UR-2/UR-3 — and none from alleys (rear may be measured from the alley centerline). Attached ADUs use the primary structure's setbacks.TMC 13.06.020.F.1; 13.06.100.F |
| Off-street parking | None. No off-street parking is required for ADUs anywhere in Tacoma — a local rule since 2019, not a transit-conditioned waiver. You may not remove the primary dwelling's required parking unless it's replaced.TMC 13.06.080.A.4.dPreviously: Off-street parking was required for ADUs — changed by Ord 28576 (2019), reaffirmed by Home in Tacoma Phase 2 |
| Owner-occupancy | None — removed by Tacoma's 2019 ADU ordinance. One exception: using an ADU (or the main house) as a short-term rental requires the owner to occupy one of the dwellings.TMC 13.06.080.A.4.g; Ord 28576 (2019) |
| Lot coverage / floor area | UR zones use floor-area ratio rather than lot coverage: UR-1 max 0.6 (1–2 units) / 0.8 (3+); UR-2 0.8/1.0; UR-3 1.0/1.2, higher with affordability bonuses. At least 10% of the lot must remain usable yard space.TMC 13.06.020.F.1, F.7 |
| Permit path & timeline | Permitted outright — building permit only, no discretionary land-use review. The city's stated issuance goal for residential new-building permits is 8 weeks.TMC 13.06.080.A.3.a; tacomapermits.org |
Worth knowing
- Tacoma liberalized ADUs citywide in 2019 — DADUs everywhere, no owner-occupancy, no parking — so HB 1337 changed almost nothing here. Guides crediting the state law for Tacoma's rules are flattening six years of local history.
- DADUs are now a 'Backyard Building' housing type that can stack behind houseplexes and rowhouses, not just single houses.
- A walkway to the street (minimum 3 ft, distinct materials) and a separate visible address are required.
- Legal lots of record are guaranteed a minimum of four dwellings under Home in Tacoma.
On our watchlist
The 2025 Annual Amendment package (minor Home in Tacoma refinements) was in public review in early 2025; the current tip sheet already reflects post-Phase-2 rules.
Check your parcel
The rules above are citywide — what you can build depends on your lot’s zone, size, and setbacks. Look yours up on the official viewers:
Primary sources
- Tacoma ADU tip sheet L-150 (03/2025)
- TMC Title 13 (eCode360)
- Home in Tacoma program
- Permit level-of-service goals
Other Washington cities
Bellevue · Bothell · Burien · Edmonds · Everett · Issaquah · Kent · Kirkland · Lynnwood · Olympia · Redmond · Renton · Sammamish · Seattle · Shoreline
Not legal advice. Every fact above cites the code section it comes from — check the cite, or ask your city’s planning department to confirm your specific lot. Spotted an error or a new ordinance? See about to reach us; corrections are logged in the changelog.