Focus On Water Division
Harmful Algal Blooms
(Also known as Toxic Blue-green Algae)
and Bacteria Sampling Results

NDEQ conducts weekly sampling for Harmful Algal Blooms (HABs), also known as toxic blue-green algae, and E.coli bacteria at 50 public recreational lakes across Nebraska from May through September and these results are updated weekly. Samples are typically collected on Monday and posted on the web site on Friday.

Current Lake(s) on Health Alert. These lakes exceed the current concentration threshold of 20 ppb of the toxin Microcystin which is associated with the presence of HABs. Lakes that have been placed on Health Alert must subsequently have two consecutive weeks of readings below 20 ppb before the alert is ended.

20 ppb of microcystin the limit that has been in effect in Nebraska since 2004, and will continue to be used through the 2017 recreational season. New research into the negative health effects of Harmful Algal Blooms (HABs) and their associated toxins has led to the Environmental Protection Agency (EPA) to propose a new threshold concentration of 4 ppb. This proposal is currently under review before being finalized. The Nebraska Department of Health and Human Services and the Nebraska Department of Environmental Quality has reviewed the proposal and the associated research and believes that the new recommendation has been made using the most current and best scientific evidence available. As such, if a recommendation becomes finalized by the EPA, the State of Nebraska intends to adopt the new lower criteria of 4 ppb at the beginning of the next recreation season.

For more information about health alerts and what to look for, go to

Precautions and Facts Regarding Harmful Algal Blooms at Nebraska Lakes and Beaches

Harmful Algal Bloom Facts * (links to an EPA website)

High E. coli Bacteria Readings, lists lakes that when sampled had unusually high readings of E.coli bacteria in the most recent sampling, which can also be a health concern. Samples above 235 colonies/ 100 ml water are considered high.

Click here for more information about bacteria and its potential health effects.

Other Lakes Sampled, lists the results for lakes which are not under Health Alert for toxic algae and their most recent sample results for bacteria are considered low.

Click on any lake name on the table below to view a chart of that lake’s sample results for HAB toxin (Microcystin) and
E.coli bacteria for the 2017 recreational season

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* This document contains links to non-NDEQ websites; these links will open in a new tab or window.