Submitted by Thurston County Health Department

The Thurston County Health Department is lifting a toxic algae advisory for Summit Lake. Laboratory results for two water samples collected on Tuesday, December 12, 2017 show microcystin toxin levels below the advisory level. The health advisory was in place for children, pregnant and breastfeeding women.

Water systems that use water from Summit Lake should be purged prior to use. Instructions on how to purge a water system are on the Thurston County Summit Lake Toxic Algae website. Citizens can also call (360) 867-2626 for assistance.

Water samples were collected over a two week period and showed microcystin and anatoxin-a below advisory levels.

Laboratory result for microcystin were 0.2 micrograms per liter and 0.120 micrograms per liter for anatoxin-a. The EPA advisory level for microcystin in drinking water is 0.3 micrograms per liter for children. Washington State’s advisory level for anatoxin-a is 1.0 micrograms per liter.

Health Department staff noted visible algae during sampling. Staff recommends avoiding contact with the lake water in areas with visible algae, and keeping pets and children out of water with visible algae.

Staff will be collecting samples for toxin testing during the week of December 18. Many residents around Summit Lake depend on the lake for drinking water. If a bloom is spotted, please report it by calling 360-867-2626.

You can learn more about toxic algae blooms and health risks at

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