What does the M suffix mean in Seattle?

Mandatory Housing Affordability, a programme requiring new development to contribute affordable housing in exchange for additional capacity. It appears across the lowrise, midrise, neighborhood commercial and commercial districts.

What is the Major Institution Overlay?

An overlay written into the code with a number and combined with a base district, appearing with lowrise and midrise districts covering roughly 501 acres together.

Which is the largest district?

Neighborhood Residential at roughly 35,634 acres, far ahead of every other classification including the maritime and lowrise districts.

Seattle Zoning Intelligence

Zoning, permitted uses, and development potential for Seattle, Washington. 284 districts with their permitted uses and building controls.

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City Context

How is Seattle zoned?

Seattle regulates land through 284 zoning districts, and the parenthetical M suffix is the mechanism behind most of the count.

M marks Mandatory Housing Affordability, a programme requiring new development to contribute affordable housing in exchange for additional development capacity. It appears across the lowrise, midrise, neighborhood commercial and commercial districts, and an M1 variant appears as well.

The scale is substantial. Lowrise 1 with the affordability requirement covers roughly 2,332 acres, Lowrise 3 about 2,042 and Lowrise 2 roughly 1,439. Those three alone exceed five thousand acres, so the affordability programme applies across a large share of the city's multifamily land.

The Major Institution Overlay is the second mechanism, written into the code with a number and combined with a base district. It appears with lowrise and midrise districts covering roughly 501 acres together.

The industrial districts are named by intent: Maritime Manufacturing And Logistics, Industry And Innovation and Urban Industrial, each carrying a height figure. The maritime districts together cover roughly 5,725 acres, protecting the working harbour.

Neighborhood Residential is the largest district at roughly 35,634 acres.

The commercial codes carry a height figure as well, so a district at 55 or 75 states the limit directly. This is pre-development intelligence, not legal advice - verify with the local planning department before acquisition.

Zoning Districts

Seattle, Washington Zoning Districts: What Do They Mean?

Zoning districts are areas regulated by specific laws that determine land use, building types, and development rules. Each district below shows its zone type. Seattle's ordinance does not state permitted uses as citywide flags, so they are read from each district's own table rather than summarised here.

Zone Code	Zone Type	Area
NR Neighborhood Residential	-	35,634.2 ac
MML-U/85 Maritime Manufacturing And Logistics Unlimited	-	4,477.9 ac
LR1(M) Lowrise Mandatory Housing Affordability	-	2,332.2 ac
LR3(M) Lowrise Mandatory Housing Affordability	-	2,042.3 ac
LR2(M) Lowrise Mandatory Housing Affordability	-	1,438.8 ac
MML-U/45 Maritime Manufacturing And Logistics Unlimited	-	683.8 ac
MML-U/65 Maritime Manufacturing And Logistics Unlimited	-	563.2 ac
LR1(M1) Lowrise Mandatory Housing Affordability	-	370.5 ac
NC2-55(M) Neighborhood Commercial Mandatory Housing Affordability	-	341.9 ac
C1-75(M) Commercial Mandatory Housing Affordability	-	336.1 ac
NC2P-55(M) Neighborhood Commercial Pedestrian Mandatory Housing Affordability	-	334.6 ac
NC3-55(M) Neighborhood Commercial Mandatory Housing Affordability	-	327.7 ac
C1-55(M) Commercial Mandatory Housing Affordability	-	326.4 ac
MR(M) Midrise Mandatory Housing Affordability	-	314.9 ac
NC3-75(M) Neighborhood Commercial Mandatory Housing Affordability	-	298.6 ac
MIO-37-LR1(M) Major Institution Overlay Lowrise Mandatory Housing Affordability	-	285 ac
NC3P-75(M) Neighborhood Commercial Pedestrian Mandatory Housing Affordability	-	268.5 ac
C2-40 Commercial	-	234.8 ac
LR3 Lowrise	-	233.3 ac
II-U/85 Industry And Innovation Unlimited	-	221.4 ac

Building Controls

What are the building controls in Seattle?

Setback, height, FAR, lot area, and density controls enforced across Seattle zoning districts.

Building height
Coverage
Density
FAR
Front setback
Lot
Lot width
Multi
Pervious
Rear setback
Side setback

Other Washington cities

Seattle zoning: frequently asked questions

What does the M suffix mean in Seattle?: Mandatory Housing Affordability, a programme requiring new development to contribute affordable housing in exchange for additional capacity. It appears across the lowrise, midrise, neighborhood commercial and commercial districts.
How widely does the affordability programme apply?: Lowrise 1 with the requirement covers roughly 2,332 acres, Lowrise 3 about 2,042 and Lowrise 2 roughly 1,439. Those three alone exceed five thousand acres of the city's multifamily land.
What is the Major Institution Overlay?: An overlay written into the code with a number and combined with a base district, appearing with lowrise and midrise districts covering roughly 501 acres together.
How are the industrial districts named?: By intent: Maritime Manufacturing And Logistics, Industry And Innovation and Urban Industrial, each carrying a height figure. The maritime districts cover roughly 5,725 acres, protecting the working harbour.
Which is the largest district?: Neighborhood Residential at roughly 35,634 acres, far ahead of every other classification including the maritime and lowrise districts.

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Zoning data is pre-development intelligence, not legal advice. Verify with the Seattle planning department before acquisition or design.