Your Seattle lot may be worth more than your house.

On 21 January 2026, Seattle did something to your property that most owners still have not registered. It deleted the single-family zone.

Not renamed. Deleted. The old NR1, NR2 and NR3 designations collapsed into one Neighborhood Residential zone that measures what you can build in units rather than in minimum lot size. Under Washington's House Bill 1110, Seattle is a Tier 2 city, which sets the floor at four units on essentially any residential lot and six units on lots near frequent transit or where affordable units are included.

Four to six units. Where one house used to sit.

If you own a house in Seattle, the value of your property is now made of two separate things that can move independently: the house standing on it, and the right to build on the dirt underneath it. For a lot of owners those two numbers are no longer close to each other.

What actually changed, in plain terms

HB 1110 is a state law that overrode local single-family zoning across Washington. It scales by city size. Tier 2 cities, meaning 75,000 people and up, must allow at least four units per residential lot, and six near transit or with an affordability component. Tier 1 cities between 25,000 and 75,000 must allow two, or four near transit. Tier 3 cities under 25,000 must allow two in qualifying areas.

Seattle implemented it through the One Seattle Plan. Bellevue implemented on the same date. On the Eastside, Kirkland, Redmond, Sammamish, Issaquah and Shoreline have all adopted compliant codes. Bothell, Bremerton and Shoreline went further and eliminated parking minimums citywide, which matters more than it sounds like it does, because required parking is frequently the thing that makes a four-unit project stop penciling.

As of the Puget Sound Regional Council's April 2026 survey, 84 percent of Washington jurisdictions had implemented middle housing regulations. This is not a pilot. It is the new baseline across the region.

What you can build now

Duplexes, triplexes, fourplexes, townhouses, stacked flats, small apartment buildings. Which of those is realistic on your specific parcel depends on lot size, lot shape, slope, tree code, setbacks, utility access and whether you sit inside a frequent transit walkshed. The zoning grants a right. The dirt decides whether the right is usable.

Why this splits your property into two prices

Before January, a buyer for your house was almost always someone who wanted to live in your house. There was one bidder type and one valuation method: what have comparable houses sold for.

Now there is a second bidder. A builder does not value your house. A builder values the finished units your lot can produce, subtracts construction cost, subtracts carrying cost, subtracts profit, and arrives at the maximum they can pay for the land. If that number is higher than what an owner-occupant will pay, the land is worth more than the house.

That is the whole mechanic. It is not complicated, and it is not new. What is new is that it now applies to ordinary residential lots in ordinary Seattle neighborhoods rather than only to parcels that were already zoned multifamily.

How to tell whether this changed anything for you

Most lots did not become development sites. Be skeptical of anyone who tells you otherwise, and be especially skeptical of an automated valuation that suddenly loves your house. Here is the honest screen, in order.

1. Lot size and shape

Four units need somewhere to go. A standard 5,000 square foot Seattle lot can often support townhouses or stacked flats. A narrow or oddly shaped parcel frequently cannot, regardless of what the zoning permits. Corner lots are worth more than interior lots to a builder because they solve access.

2. Distance to frequent transit

This is the single biggest variable. Six units instead of four is a fifty percent increase in what the land produces, and it flips a marginal site into a viable one. If you are inside a frequent transit walkshed, find out. It is the difference between a mild bump and a materially different number.

3. Slope and trees

Seattle is not flat and Seattle has a tree ordinance. A steep site adds foundation and retaining cost that can eat the entire development margin. Exceptional trees can remove buildable area outright. Both are routinely ignored by owners doing the math on the back of an envelope, and neither is ignored by a builder.

4. What is next door

Assembly value is real. Two adjacent lots that each support four units are worth more together than apart, because one bigger site is cheaper per unit to build. If your neighbor is also thinking about selling, that is a conversation worth having before either of you lists.

If you are keeping the house

This still matters, in two directions.

The upside is that the same rules apply to you. An accessory dwelling unit, a detached unit in the back, a conversion to a duplex: these are now permitted uses in places where they used to require a variance you were never going to get. That is a rental income path on land you already own, which is the cheapest real estate you will ever acquire because you already own it.

The downside is that your neighbors got the same rights. Look at the parcels around you and ask what could realistically be built on them, because someone eventually will. This is not a reason to panic. It is a reason to know.

If you do go the rental route in Seattle, know the rules before you buy the first appliance. The 2026 residential rent increase cap is 9.683 percent, calculated as seven percent plus CPI for the Seattle-Tacoma-Bellevue area and recalculated annually. Seattle requires 180 days notice before a rent increase, and increases above ten percent trigger Economic Displacement Relocation Assistance notice requirements.

What I would actually do

If you are thinking about selling in the next two years, get the land valued separately from the house before you do anything else. Not an automated estimate. A real read on unit count, transit proximity and what a builder in this market would pay for the site.

If the land number is close to the house number, sell the house the conventional way and stop thinking about it.

If the land number is meaningfully higher, you have a different transaction on your hands, with a different buyer pool, a different marketing approach, different contract terms around feasibility periods, and different tax consequences. Do not run that one on instinct.

And if you are not selling at all, spend twenty minutes finding out what your lot now permits. It is your asset. You should know what it does.