Environmental Health
Scatter Creek Aquifer Characterization Project
  Scatter Creek Aquifer - Septic System Management Project  

Advisory Committee Recommendations

The Citizen's Advisory Committee's recommendations to keep water in the Scatter Creek aquifer safe to drink now and in the future were approved and adopted by Resolution H-3-2014 of the Thurston County Board of Health on December 16, 2014. The Citizen's Committee met for two years to learn about the aquifer. They concluded that:

  • The Scatter Creek Aquifer is vulnerable to contamination from septic systems and land use activities.
  • Nitrogen levels in the aquifer have decreased over time and seem to be trending lower.
  • Current aquifer conditions and worse-case model results do not warrant taking regulatory action at this time. The groundwater model predicts that average nitrate concentrations in even the most vulnerable part of the study area will be less than half the maximum contaminant level of 10 mg/l.
  • The committee wants to be cautious and monitor water quality so, if needed, we can take action before it is too late. Ideally monitoring should evaluate trends, the accuracy of the computer model, water quality in deeper areas of the aquifer, the extent and duration of water quality spikes, chemicals of emerging concern, and pathogens such as viruses.
  • In general, zoning, land use and health regulations have protected the aquifer from nitrate and many other contaminants. However, health and land use regulations can be strengthened to help assure the optimal placement of new septic systems and wells to minimize the potential for contaminating drinking water supplies.
  • The committee believes that with proper information, education, and incentives, area residents will be good stewards and take action to protect the aquifer.

Based on these conclusions, the Scatter Creek Aquifer Citizen's Committee discussed and unanimously decided on their recommendations.

Project Summary

The goal of the project was to make sure water in the Scatter Creek Aquifer is safe to drink now and in the future. The three-year project included groundwater monitoring, scientific modeling, and community input. A citizen advisory committee evaluated scientific data and modeling for potential impacts on the aquifer and made recommendations to the Thurston County Board of Health and Board of County Commissioners. Funding for this project was provided by the Washington State Department of Ecology.


Click to see maps of Scatter Creek Aquifer Area

Residents living in the Scatter Creek Aquifer Area (click on the map for a larger view of the area) rely on groundwater for their drinking water. Water in this aquifer is highly vulnerable to contamination because the sandy, gravelly soils do not effectively filter out contamination. Unlike other areas, there is not another deeper aquifer below the Scatter Creek Aquifer; it is a sole-source aquifer.

Test results from private and community wells show nitrates and coliform bacteria are getting into the water. Currently, most wells tested in the area meet drinking water standards. At levels above drinking water standards, these contaminants can cause illness. We are concerned because, at times, nitrate levels in this area have been some of the highest in Thurston County, with some wells exceeding drinking water standards.

For Past Studies and Reports click here.

Key Activities:

Citizen Advisory Committee (clickable link)

Committee members were appointed to the committee by the Board of Health and must live, own property, or work in the Scatter Creek Aquifer Area. The committee typically met on the first Wednesday of the month at the Rochester School District Board Room. They learned about the area and risks posed to the drinking water by septic systems, helped determine if levels of contamination are likely to cause public health concern, and developed recommendations for an action plan to ensure water in the Scatter Creek Aquifer is safe to drink now and in the future.

Your feedback

Throughout the two year process, you shared your thoughts on the project. Your feedback was important to us because you, as residents or property owners in the Scatter Creek Aquifer Area, are the people who drink the water and are affected by the issues. Your thoughts and concerns helped the Citizen's Advisory Committee shape their recommendations and we thank you.

Here's what we heard from you:

Contact us

If you have additional questions or comments about the project, please send us an e-mail or call 360-867-2582.


STudies & Links
  • Gerald Tousley
    Project Manager
  • Jane Mountjoy-Venning
    Community Liaison
  • Send an e-mail or sign-up for updates here.
This page last updated: 07/02/21