Official Government Website

Cyanobacteria Harmful Algal Blooms

DEQ and the Idaho Department of Health and Welfare (DHW) each play a role in identifying, responding to, and monitoring cyanobacteria harmful algal blooms (HABs).

The health advisory map is available on DHW’s Recreational Water Health Advisories web page.

Our staff is responsible for sampling Idaho water bodies and analyzing water quality data. We provide the sample results to DHW and the public health district in the area where a citizen reported the HAB, and they decide if it warrants a health advisory.

Water Quality Test Results

As water quality sample results become available, you will see them in the table below. 

County Waterbody Sample Date *Threshold Level
Power American Falls Reservoir 07-27-2023 Below
Adams Brownlee Reservoir 11-27-2023 Below
Twin Falls Cedar Reservoir 12-28-2023 Below
Elmore/Owhyee CJ Strike 09-07-2023 Below
Bonner Cocolalla Lake 09-26-2023 Above
Twin Falls Dierkes Lake 08-31-2023 Below
Kootenai Fernan Lake 09-07-2023 Above
Blaine Fish Creek Reservoir 07-31-2023 Below
Adams Hells Canyon Reservoir 10-26-2023 Below
Fremont Henry’s Lake 10-18-2023 Below
Fremont Island Park Reservoir 09-18-2023 Below
Canyon Lake Lowell 09-18-2023 Below
Elmore Little Camas reservoir 07-27-2023 Below
Blaine Little Wood River Reservoir 07-13-2023 Below
Blaine Magic Reservoir 08-29-2023 Below
Camas Mormon Reservoir 08-29-2023 Below
Twin Falls Murtaugh Lake 07-27-2023 Below
Bonneville Palisades Reservoir 09-06-2023 Below
Twin Falls Salmon Creek Falls Reservoir 12-28-2023 Below
Kootenai Spirit Lake 06-28-2023 Below

*For more details on threshold values, please click on the “Idaho DEQ Cyanobacteria Harmful Algal Bloom Information” tab below.

Report a Potential Harmful Algal Bloom

Report a potential harmful algal bloom: 

Health Concerns

Idaho’s health agencies offer citizens education and advice on cyanobacteria exposures. Contact the Idaho Department of Health and Welfare or your local public health district for health concerns and cyanobacteria information.

This accordion will not appear on the screen

ver: 3.5.1 | last updated:
Jump back to top of page button