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Thurston County, Washington

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Summary of the work

Thurston County government operates many water-related programs, and also studies area waters to identify specific projects to keep water safe for drinking, farming, fishing and recreation. Much of this work is mandated by state or federal laws.  Most pollution enters local waters with rainwater runoff that picks up vehicle and lawn chemicals, animal poo, and uncovered topsoil at construction sites. Learn about polluted runoff.

Drinking Water   |   Construction Site Water-Protection Regulations   |   Domestic Well rules (the Hirst Decision)   |   Drainage Manual for New Construction   |   Find Water Levels & Precipitation Amounts Near You  |   Flood Programs   |   Lakes Management District Programs   |   Lake Water Quality   |   Septic Systems & Wells   |   Shoreline Building Regulations   |   Stormwater Utility    |   Stormwater Management Program   |    Swimming & Closed Beach Advisories   |   Water & Sewer Utility  |  Water Terms & Definitions       



This is a list of projects conducted by Thurston's Community Planning department. New studies added over time.

Project Name Water Area Studied ​Project Web Page (Find documents & details)
Healthy Watersheds Study

(also called Science to Local Policy)
​All Thurston County watersheds 

Link to the Science to Local Policy web page

​Chehalis Watershed Cooperative ​Chehalis Watershed ​BoCC Resolution


Link to Chehalis Watershed Coop web page

​Deschutes Watershed Land Use Analysis ​Deschutes Watershed Link to the Deschutes Study web page

Project Report

BoCC Resolution 15374…

​Basin Plans ​Area basins: Chambers-Ward-Hewitt, Green Cove Creek, Indian-Moxlie, McAllister-Eaton, Percival Creek, Salmon Creek, Woodland-Woodard Link to basin plans web page
​Low Impact Development Water areas affected by Thurston County Code Link to LID Project web page
​Shellfish Protection District ​Henderson Inlet & Nisqually Reach Link to Shellfish Protection District web page
​Black Lake Basin Study ​Black Lake Basin ​Link to Black Lake Basin Study web page
​McLane Creek Basin Study ​​McLane Creek Basin ​Link to McLane Basin Study web page
​Woodard Creek Basin Study ​Woodard Creek Basin ​Link to Woodard Creek Basin Study web page
​WRIA 11 Implementation Plan ​WRIA 11 / Nisqually Link to WRIA 11 Implementation Plan document (PDF)
​WRIA 13 Deschutes River  ​​WRIA 13 Deschutes River  ​Link to WRIA 13 Plan & Studies web page
​Watershed Characterization Studies ​Area watersheds: Deschutes, Henderson Inlet, Nisqually, Totten/Eld Inlet ​Link to watershed characterization studies web page



Where the pollution comes from: Rainwater runoff mostly

Our area gets about 50 inches of rain each year. The runoff flows into nearby streams, rivers, lakes and the Puget Sound carrying whatever it picks up along the way. Vehicle fluids from roads, dog poo left on yards and park grounds, fertilizers and pesticides from lawns and fields flows untreated into the water our families and pets play in, fish from and drink.

Which local waters are studied

Water flows across geographical and political boundaries. A river that flows mostly through Thurston County may have a headwaters upstream and in a different city and county. Some rivers that start here, flow downstream into other cities and counties. That's why water areas are identified not by city or county, but by a common point to which they drain. These water areas are divided into basins, watersheds, and water resource inventory areas (WRIAs). 

​Basins ​Watersheds ​WRIAs
​Chambers Ward Hewitt ​Deschutes River ​Chehalis 22/23
​Green Cove ​Chehalis ​Deschutes River 13
​Indian Moxlie ​Henderson Inlet ​Kennedy-Goldsborough 14
​McAllister-Eaton ​McLane Creek ​Nisqually 11
​Percival ​Nisqually Reach
​Salmon Creek Totten-Eld Inlet
​Woodard Creek
​​Black Lake Basin 


Regulatory Reasons for the work

Many of the County's pollution reduction activities are mandated and monitored by the U.S. Environmental Protection Agency (EPA) and by the Washington State Legislature.  Thurston County government has a clean water permit from the EPA. When the County issues building and septic permits, builds County roads, or conducts any work, it must comply with federal and state regulations. Find details on the Stormwater Management Program page.  Also, Washington's Watershed Management Act (RCW 90.82) encourages local communities to protect local water resources and habitat in their planning work. State law regarding WRIAs - WAC 173-500-040

Project funding

Studies are often funded by state or federal grants. Improvement projects may be funded by County utility, permit or application fees. All project funding sources are approved by Thurston's elected officials, the Board of County Commissioners.

Which County Regulations & Codes are Affected

Most building development and zoning regulations.