Puget Sound Mapping Project

Comparing Planned Versus Actual Growth Patterns

Note: Click on the map below to be connected to an interactive online version

What You Can Learn From These Maps

Growth rates slowed markedly during the recession and only recently started to match pre-recession rates. King County has captured almost half of the areas new housing units between 2000 and 2017. Within King County, a significant number of units were constructed within a few miles of downtown Seattle. Snohomish and Pierce County have also seen high levels of growth. In many rural areas, growth has clustered within a few miles of urban growth boundaries.

Increasing populations and development typically results in loss of vegetation and more pavement and roofs (also known as impervious surfaces). Increases in the amount of impervious surfaces reduces the amount of water that is naturally absorbed into the ground and reduces the amount of ground water available for drinking.  It increases the run-off of contaminants like fertilizers and pesticides to rivers, lakes and the ocean. Ultimately this reduces the amount and quality of water that is available for people, aquatic life, and wildlife. Threats to water quality challenge our best efforts to reduce impacts of urbanization.

One of the Puget Sound Partnership’s Vital Sign targets for 2020 is that at least 85% of regional growth occur within urban growth areas (or that less than 15% of growth is occurring in rural areas). Overall, as of 2017, the region is meeting this goal, with less than 10% of growth occurring in rural areas over the past few years.  However, recently, as growth continues to increase, development is starting to shift to rural areas, and some specific counties continue to struggle to meet their individual goals. Go here for line graph.

Dept. of Ecology’s Watershed Characterization Project designated approximately 3,000 “Watershed Characterization Assessment Units” (AUs) throughout the Puget Sound.  Overall, our mapping indicates that these AUs saw the creation of 430,316 new housing units between 2000 and 2017; or an increase of just over 26%. Areas of high housing growth outside of urban growth boundaries are broadly associated with coastal plains near cities, within the valleys of the Cascade Mountains and near freeways, highways or major roadways. A map of growth within Ecology’s AUs shows a broad depiction of growth patterns.

In 2017, our region-wide mapping analysis indicates that most housing development within urban growth areas, has occurred primarily in Intensive Urban (12,748 units) and Urban Character Residential (6,276 units) land use categories.  In rural areas, the Rural Character Residential (1,589 units) land use category has experienced the most growth. Other land use categories accounted for 463 new units. Mixed Use and Commercial Area growth rates are increasing with 2017 rates exceeding the annual average rate from 2000-2017. In addition, Low Density Urban Residential (1.1-3 Units/Acre) areas also saw higher rates in 2017 than the long-term average annual rate.

Most of the region’s urban growth is occurring in Seattle, Bellevue, Everett and Tacoma and their proportion of regional growth appears to be increasing. In addition, large master planned communities such as the Issaquah Highland, Snoqualmie Ridge and Redmond Ridge show intensive new housing growth. In the southern portions of the region, Joint Base Lewis-McChord (JBLM), Frederickson and Puyallup are experiencing the heaviest housing production. Mill Creek, Alderwood, Marysville, and Lake Stevens are more recent heavy growth counterparts on the northern end of the region. Whatcom, Skagit, Kitsap, and Thurston counties are also showing strong yearly increases in both rural and urban areas. Rural development tends to exceed urban development levels in other counties.

In addition to analyzing growth patterns within rural areas, watershed assessment units and land-use categories, there are numerous ways in which the Puget Sound Mapping Program’s map layers can help support a wide range of planning and environmental restoration efforts.

Please contact Charlene Andrade via email at charlene.andrade@commerce.wa.gov and provide details about the nature of the problem (such as incorrect categorization of a land use, error in boundaries, trouble displaying, or downloading).

Trends in Residential Development: 2001 to 2017

The Puget Sound region has experienced substantial amounts of new residential development since 2001.  The first map below shows new housing units built between 2001 through 2017.  The second map shows just units built between 2016 and 2017.  Each dot on these maps represents approximately 10 new housing units.

Puget Sound Housing Growth

Note: Click on the map icons below for a larger version

New Housing Units 2001 - 2017

New Housing Units, 2017

Housing Total Units over Time (pre 1900 - 2017)


Project Purpose

To provide a mapping tool for regional and local governments that shows growth patterns around the Puget Sound using consistent methods across jurisdiction boundaries.

This interactive mapping tool allows decision makers to compare expected and actual development patterns over the landscape and across land use zones.

The insights gained from these maps enables more data-driven decisions and can be integrated with resource mapping for comprehensive planning.

Project Funding

This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement PC-00J27601 with the Washington State Department of Ecology. The contents of this web page and its documents do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

Need Help?

Charlene Andrade, Senior Planner
Growth Management Services
Phone: 360-725-3063


Webinar: A Walk Through the Maps

Puget Sound Mapping Project Description (PDF)

Using the Maps: A Friendly Tutorial

Additional Information and Mapping Tools

Washington State Department of Ecology

Puget Sound Watershed Characterization Project Compares areas of Puget Sound basin in terms of sustainability and value for restoration and protection.  Provides information on individual watersheds in terms of:  water flow processes, water quality processes, and fish and wildlife habitats.

Coastal Atlas: Includes maps on flood hazard maps, shoreline biology, hydrography, spill response, shoreline modifications and the Shoreline Management Act jurisdictions as well as geomorphology.

Water Quality AtlasShows approved and in-development water quality improvement projects state-wide, water quality status for a particular location, and location of permitted outfalls.

Washington State Department of Natural Resources


Washington State Department of Fish and Wildlife

SalmonScape: This web application  displays a wide range of data related to salmon distribution, status, and habitats. The data sources used by SalmonScape include stream specific fish and habitat data, and information about stock status and recovery evaluations.

SCoRE (Salmon Conservation and Reporting Engine): This WDFW application leads you to maps for different WRIAs and summarized data and information about salmon conservation for each WRIA.

StreamNet: Salmon GIS data and maps for the Pacific Northwest are also available.