Protecting Public Health and the Environment.

Recreation Water Quality Health Advisories

This page provides information related to current recreation water quality health advisories involving cyanobacteria harmful algal blooms (HAB) and E. coli bacteria. The map and information table are updated with the most current information as health advisories are issued and lifted throughout the season.


Remember: Only a fraction of all water bodies in Idaho are monitored due to limited physical and monetary resources. The absence of an advisory is not an indication that a HAB or E. coli is not present at a water body. You are your own best advocate when ensuring your safety, and that of your family and pets. Be aware and "when in doubt, stay out."









Click pin for detailed information. Active HAB Advisory: Active E. coli Advisory: Lifted Advisory:

Active Harmful Algal Bloom Advisories

County Waterbody Date Issued Dominant Taxa DEQ Contact
Washington Brownlee Reservoir 7/10/2020 Anatoxin-a, Microcystin Boise Regional Office, Chase Cusack, (208) 373-0550
Kootenai Fernan Lake 7/22/2020 Dolichospermum, Microcystis, Gloeotrichia Coeur d Alene Regional Office, Bob Steed, (208) 769-1422
Latah Spring Valley Reservoir 10/2/2020 Dolichospermum, Woronichinia Lewiston Regional Office, Sujata Connell, 208-799-4370
Valley Cascade Reservoir 10/5/2020 Microcystin Boise Regional Office, Chase Cusack, (208) 373-0490

Lifted Harmful Algal Bloom Advisories

County Waterbody Date Issued Date Lifted
Ada Silver Lake 4/28/2020 8/21/2020
Adams Hells Canyon Reservoir 7/10/2020 11/10/2020
Twin Falls Cedar Creek Reservoir 8/11/2020 11/13/2020
Twin Falls Thorn Creek Reservoir 8/11/2020 11/13/2020
Camas Mormon Reservoir 8/21/2020 11/13/2020
Canyon Lake Lowell 9/4/2020 11/23/2020
Bonner Lake Cocolalla 9/4/2020 10/28/2020
Owyhee CJ Strike Reservoir 9/18/2020 10/29/2020
Latah Hordemann Pond 8/11/2020 11/16/2020
Bonner Round Lake 10/2/2020 10/28/2020
There are no current E. coli advisories at this time.



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Report a Bloom

While you're recreating, notify us of a possible harmful algal bloom. You can contact one of our six regional offices, send an email to, or download the bloomWatch app. To help us investigate, please provide photos and water body location.

Download the bloomWatch app to learn what to look for and report what you found. Learn more.

Additional Information

Related Pages

Cyanobacteria Harmful Algal Blooms

Cyanotoxins: Information for Public Water Systems