Lake water quality monitoring & protection

Most lake water quality monitoring in Washington is currently conducted by counties, local health departments, lake associations, and volunteer groups. Our scientists coordinate algae and invasive-plant monitoring and participate in a periodic national survey. We test several lakes annually for toxic chemicals.

We also keep a statewide clearinghouse for lake data from across the state. This includes historical monitoring and current sampling by our scientists and data compiled under local-government projects we fund. Data, including some photographs and lake-bottom maps (bathymetry), are found Lakes Environmental Data application. Look up a lake below.

See the Lakes Environmental Data for the full database.

We coordinated a large lake-monitoring program from 1989 – 1999 to identify statewide water quality concerns. We tested for dissolved oxygen, water clarity, temperature, and contaminants. While this program is no longer funded, we maintain these data. We also monitor some lakes each year for toxic metals and other chemicals.

We participate in EPA's National Lakes Assessment every five years. Data are collected on a random sampling of lakes representing different regions of the state.  We partnered with the Environmental Protection Agency (EPA) on this project in 2007, 2012, and 2017.

Resources and links