Snapshot Day Results: E. coli Bacteria
See Full Monitoring Results and Maps Below
E. coli bacteria in water can make people sick.
E. coli bacteria is found in the feces of warm-blooded animals, including wildlife, livestock, waterfowl, and humans. High levels of E. coli in water indicate fecal contamination and the possible presence of pathogens harmful to humans. Human waste from poorly functioning septic systems, manure runoff from fields, and pet waste are just a few sources of E. coli contamination in local lakes and streams.
On Snapshot Water Monitoring Day, volunteers test for E. coli levels at sites across the watershed. While contamination levels and possible causes vary from site to site, we consistently find E. coli concentrations that do not meet state water quality standards. On the maps below, these sites are shown in yellow and red.
Explore full results below. Click on any map to zoom in.
2024 E. coli Levels
In 2024, several monitoring sites showed levels of E. coli that exceed state safety standards. Like some previous years, we found the highest concentrations in the lower portion of the watershed.
Depending on the location, contamination could have been caused by animal waste, sewage overflows, or poorly functioning septic systems. TWF is working with partners to determine the pollution sources and potential solutions.
2023 E. coli Levels
In 2023, several monitoring sites showed unusually high levels of E. coli, with the largest concentration in the lower portion of the watershed. Depending on the location, contamination could have been caused by animal waste, sewage overflows, or other pollution.
2022 E. coli Levels
In 2022, E. coli levels at testing sites in the upper portion of the watershed were mostly safe to moderately elevated, with a few areas of critical concern. Testing sites in the lower portion of the watershed showed moderate to critically elevated E. coli levels.
2021 E. coli Levels
In 2021, many monitoring sites across the watershed showed E. coli concentrations that did not meet state water safety standards. Depending on the location, contamination could have been caused by animal waste, sewage overflows, or other pollution.
2020 E. coli Levels
In 2020, several monitoring sites showed unusually high levels of E. coli, including Cherry Creek near Winona Lake Limitless Park, likely caused by pet waste. Read more about TWF’s response to these findings, our plans for future action, and how you can be part of the solution today.
2019 E. coli Levels
In 2019, several monitoring sites revealed E. coli levels that did not meet state water safety standards, including high concentrations around streams in the southern portion of the watershed.
2018 E. coli Levels
In 2018, though several sites in the upper watershed showed unsafe levels of E. coli, results had significantly improved from the previous year.
2017 E. coli Levels
In 2017, many monitoring sites revealed E. coli concentrations that did not meet state water safety standards. Depending on the location, contamination could have been caused by animal waste, sewage overflows, or other pollution.