Lake Water Quality

From 1989 through 1997, Ecology and a team of volunteers monitored about 60 lakes annually. Ecology staff visited each lake in the spring or early summer and again in late summer while volunteers collected data every two weeks. In 2000, statewide funding stopped.

An EPA-funded National Lakes Survey team collected data on a randomized sampling of lakes in 2007 and again in 2012. At present, most lake monitoring is done by local health departments, lake associations, and volunteers, aside from a few specific surveys, as noted below. All of these data are now folded into the Lakes Environmental Data database.

Lakes Publications contains all Ecology publications on lakes, organized by year.

Washington State Toxic Algae has a map-based database with toxic-algae sampling results from lakes around Washington state.

Aquatic Plant Monitoring describes how Ecology is helping lakes with invasive nonnative plants.

Aquatic Plants, Algae, and Lakes is a page at Ecology's Water Quality Program that has general information on Aquatic Plants and Lake Management.

Aquatic Pesticide Permits describes permits needed for freshwater use of herbicides, physical plant-control methods, nutrient-inactivation products, or biocontrols.

Mercury in Fish Tissue tests mercury levels in fish in six lakes annually.

Contaminants in Sediment Cores tests core samples from three lakes annually for persistent chemical trends. These include lead, mercury, and organic contaminants, such as PAHs, depending on the year of study.

Freshwater Fish Contaminant Monitoring Program tests fish and fresh water for toxic chemical contamination.

WAC 173-201A-240 Toxic Substances in the Water Quality Criteria for Surface Waters of the State describes legal limits of certain chemicals in Freshwater and Marine Waters.


William Hobbs (; (360) 407-7512).

Related information

Water Supply Bulletins from USGS in 1973 and 1976 focused on lakes.

King County Lake Services and Information offers information about lakes and lake management in Washington's most populous county.

How you can help protect your favorite lake is another resource from King County.

Lakes - Snohomish County links to that county's monitoring website.