MHA Environmental Impact Statement

What is MHA? Mandatory Housing Affordability (MHA) is a new policy to ensure that Seattle's growth brings affordability. MHA will require new development to include affordable homes or contribute to a City fund for affordable housing. To put MHA in effect, we need to make zoning changes that add development capacity and expand housing choices. 

For more, read our MHA overview and a technical summary of how MHA works. 

We have a new web map! Our latest interactive map shows how we developed the citywide MHA zoning proposal that Council is reviewing. However, our EIS web map is still available if you want to see the zoning scenarios analyzed in the Preferred Alternative and Draft EIS Alternatives 2 and 3. 

Final Environmental Impact Statement (EIS)

Published on November 9, 2017, our Final EIS includes a Preferred Alternative for implementing MHA throughout the city in multifamily and commercial zones, urban villages, and urban village expansions studied during the Seattle 2035 Comprehensive Plan process. The Preferred Alternative resembles legislation we will send to the City Council for review and adoption. Key features of the Preferred Alternative include:

  • Implementing MHA broadly to help meet the City's goal for affordable housing production
  • Locating more housing in areas with high access to opportunity and low risk of displacement
  • Allowing more people to live and work close to transit by expanding urban villages to a full 10-minute walk from frequent transit stations
  • Moderating development capacity increases in areas with environmental constraints and within 500 feet of freeways

The Final EIS completes the environmental review process. We studied four alternatives: the No Action Alternative; two Action Alternatives studied in the Draft EIS; and the Preferred Alternative, a hybrid of the Draft EIS Action Alternatives that reflects more than two years of community input. 

What is the Final EIS?

The Final EIS identifies and describes potential impacts on the environment that could result from changing zoning to implement MHA. For more on the environmental review process watch our What is an EIS? video. The Washington State Department of Ecology also has information about SEPA and the EIS process.  

MHA Final EIS (61 mb)

Note: marked public comment documents are provided with the individual Chapter downloads below.

MHA Final EIS Appendices (124 mb)

MHA EIS web map 

Introduction and Table of Contents

1.0 Summary

2.0 Description of the Proposal and Alternatives

3.0 Environmental Analysis

4.0 Comments & Responses

5.0 References

6.0 Distribution List



MHA Draft EIS Appendices

Weekly Wonk: What is an EIS?

Weekly Wonk - Environmental Impact Statements (EIS)