Guide · Tacoma · Pierce County · Updated July 2026
How many units can you build in Tacoma?
If you own or are evaluating a residential lot in Tacoma, the first question is almost always the same: how many homes can legally go on it? Since Washington's HB 1110 middle-housing law took effect, the answer for most Tacoma lots is now more than one. Tacoma's Urban Residential zones regulate middle housing by minimum lot area per unit (1,500/1,000/750 sf), with affordability bonuses that sharply raise the count — so units scale with lot size, not a fixed per-lot number.
Tacoma at a glance: no fixed per-lot unit cap — capacity is set by the building envelope and density, plus up to 2 ADUs under HB 1337. Source: Tacoma Urban Residential standards / TMC (2024–2025).
What Tacoma's adopted code allows
Tacoma's Urban Residential zones regulate middle housing by minimum lot area per unit (1,500/1,000/750 sf), with affordability bonuses that sharply raise the count — so units scale with lot size, not a fixed per-lot number. Transit proximity affects parking, not unit counts.
The details: affordability and building-retention bonuses sharply raise the count — minimum lot area per unit improves from 1,500/1,000/750 sf down to as little as 750/500/375 sf. These are Tacoma's city-wide standards, per Tacoma Urban Residential standards / TMC (2024–2025); the exact figure for a specific parcel — its zone, lot size, transit proximity, and critical areas — is what a Civexa report resolves.
What actually fits: floor area, height, and setbacks
HB 1110 and the city code set the right to a number of units; the zone's building envelope sets what physically fits. Floor-area ratio, lot coverage, height, and setbacks together decide whether those homes pencil as detached cottages, a townhouse row, or a stacked-flat building. Civexa computes this envelope for Tacoma zone by zone, so the unit count you see is one the zoning can actually hold.
What can shrink it: critical areas
Steep slopes, wetlands, streams, and flood zones can override the unit math on a specific parcel. A lot that qualifies for the maximum on paper may be constrained once environmentally critical areas are mapped. Civexa screens FEMA flood, slope, and county critical-area layers for every Tacoma address so you find this out before you make an offer, not after.
Get the exact number for your Tacoma parcel
The figures above are Tacoma's city-wide rules. The number that matters is the one for your address — its zone, lot size, transit proximity, and critical areas. Civexa turns that into a full feasibility report in about a minute: unit count, buildable envelope, a preliminary pro forma, utilities, and permit path.
Run a Tacoma feasibility report →
Frequently asked
How many units can I build on a residential lot in Tacoma?
Tacoma's Urban Residential zones regulate middle housing by minimum lot area per unit (1,500/1,000/750 sf), with affordability bonuses that sharply raise the count — so units scale with lot size, not a fixed per-lot number. That is per Tacoma Urban Residential standards / TMC (2024–2025). The exact number for a specific parcel still depends on its zone, lot size, transit proximity, and critical areas — run a Civexa report for the parcel-level figure.
Can I add ADUs on top of that in Tacoma?
Washington's HB 1337 allows up to two accessory dwelling units on a residential lot. In some cities they count toward the middle-housing total and in others they are separate — your Civexa report applies Tacoma's specific rule.
What unlocks the maximum in Tacoma?
Affordability and building-retention bonuses sharply raise the count — minimum lot area per unit improves from 1,500/1,000/750 sf down to as little as 750/500/375 sf.