Updated October 2026. General education, not legal, zoning, or financial advice. Confirm what your lot allows with SDCI and a licensed architect.
The short answer: since January 2026, most Seattle Neighborhood Residential lots allow stacked flats, apartments built one above another, at one unit per 600 square feet of lot area. A typical 6,000 square foot lot can hold around ten apartments, often with no parking required. For owners who want long-term income from their land, that is a new kind of option.
What changed
Seattle rewrote its Neighborhood Residential zoning in January 2026 to meet state middle housing law. The rules now favor small apartment buildings on ordinary residential lots (City of Seattle summary):
- Density: the greatest of one unit per 600 sq ft of lot area for stacked flats, four units on any lot, or six near major transit or with two affordable units.
- Floor area: up to a 1.8 floor area ratio for stacked flats at the highest density, or 2.0 with qualifying tree retention or a Green Factor of 0.6. Accessible stacked units in buildings under ten units do not count toward floor area.
- Height: 32 feet, or 42 feet in qualifying cases.
- Parking: none required for units of 1,200 sq ft or less, or near major transit.
- Lot coverage: up to 50%.
What a lot can hold
| Lot size | Stacked flats by density | Floor area at 1.8 FAR |
|---|---|---|
| 4,000 sq ft | About 6 | About 7,200 sq ft |
| 5,000 sq ft | About 8 | About 9,000 sq ft |
| 6,000 sq ft | About 10 | About 10,800 sq ft |
| 7,500 sq ft | About 12 | About 13,500 sq ft |
Stacked flats vs. townhomes
Townhomes are usually built to sell, one owner per home. Stacked flats fit more homes on the same lot, rent well as smaller units, and suit an owner who wants to hold the building and its income. They are also a different building type: a stacked building is designed and permitted differently from townhomes, with more structure and fire protection, so design and cost planning matter early.
Build to sell, or build and hold
If you want cash from your land, selling or partnering is usually faster. If you want income for the long term, a small apartment building you own can be the stronger play. You fund the project, typically with a construction loan, and keep the building. We call that path Build and Hold: we lead the design and permits, build it, lease it up, and manage it for you.
Common questions
How many units can I build on a Seattle lot in 2026?
In Neighborhood Residential zones, stacked flats are allowed at one unit per 600 square feet of lot area, with a minimum of four units on any lot and six near major transit or with two affordable units. A 6,000 square foot lot can hold around ten flats, subject to floor area, height, setbacks, trees, and lot coverage.
Do stacked flats need parking in Seattle?
No parking is required for units of 1,200 square feet or smaller, or for lots within a half-mile walk of a major transit stop.
How tall can a stacked flat building be?
The base height limit is 32 feet plus pitched-roof allowances, or 42 feet in some cases, including stacked units that meet a Green Factor score of 0.6.
Can I keep my land and own the building as a rental?
Yes. Many owners build and hold. You fund the project, usually with a construction loan, and own the income afterward. We can design, build, lease up, and manage it for you.
Start with a Landowner Consult
A complimentary consult on what your lot can hold: stacked flats, townhomes, a sale, or a partnership, and what each takes in cost and time. If there is a fit, we follow up with a proposal scoped to your site.
Related: How a Seattle Home Gets Built, a plain-language guide to the stages, the money, and the risks of a development project.