Bacteria Monitoring Information

The Nebraska Department of Environmental Quality (NDEQ) routinely samples lake water for bacteria at many swimming beaches across the state. These samples are taken in conjunction with the samples that the state collects for toxic blue-green algae. People planning on swimming at these beaches may want to consider any health risks from exposure to bacteria as well as toxic blue-green algae. Therefore, NDEQ is providing this information so that the public can make a more informed decision.

What are the risks from bacteria?



Bacteria at swimming beaches or in the lake water can cause gastrointestinal problems (such as diarrhea) if swallowed. Typically, exposure to skin does not result in skin problems, such as rashes or swimmers’ itch. Although swallowing water can lead to flu-like symptoms, the health effects are typically not life-threatening.


What level is considered safe?


Although each person and family must make their own decision as to what risk they want to take by swimming in the lake, the state is providing guidelines below, which are based on federal Environmental Quality Agency (EPA) risk-based information. Although “risk-based” means that there may be a greater likelihood of developing an illness if you consume water containing bacteria at or above these levels, it does not mean that levels below the guidelines are absolutely “safe.” These are simply guidelines, and the public needs to make their own decisions on the level of risk they are willing to take.

For a Single Sample: 235 counts (or higher) per 100 ml is considered a higher risk for illness through ingestion.
Long-term Average: 126 counts (or higher) per 100 ml is considered to be a higher risk for illness through ingestion.

To view the most recent single sample counts at Nebraska lakes, refer to the bacteria column on
Bacteria and Toxic Algae Monitoring: Weekly Results . To find the long-term averages for a particular lake, click on the lake name on that page, and it will provide you all of the year’s data for both bacteria and toxic algae

What should I do if I find the levels are above the risk-based guidelines?
  • Avoid any situation which could cause you to swallow lake water
  • If you have been in contact with lake water, shower afterward
  • If you have been in contact with lake water, wash hands before eating
Additional frequently asked questions:

Where does the bacteria come from?


Bacteria exist naturally in the environment. They get into lakes and rivers via wildlife, human sources, and from run-off after a rainfall event. Wildlife and livestock that walk or swim in water can leave behind feces, a source of bacteria. Septic systems that aren’t working properly and wastewater treatment facilities that discharge untreated wastewater are the main human sources of bacteria. Livestock waste containing bacteria that is applied to farmland as a fertilizer can wash into a stream or lake during rain. There are numerous sources of bacteria, but these are the primary ones.