A new report finds potentially unsafe levels of fecal contamination at 85% of monitored recreational waterways in Missouri, raising concerns for people swimming, boating and spending time in the state’s rivers, lakes and streams.
The Environment America Research & Policy Center analyzed water quality data from the National Water Quality Monitoring Council’s Water Quality Portal collected in 2024 and 2025. Researchers examined 202 monitoring locations across Missouri and found potentially unsafe levels of fecal indicator bacteria at 171 locations, or 85% of the sites, on at least one day of testing.
The findings come days after the Missouri Department of Natural Resources warned of dangerously high E. coli levels in the Big River.
The report does not mean the waterways were contaminated every day or that all recreational waterways in Missouri are unsafe. The analysis focused on specific monitoring locations and the days those locations were tested. Some waterways may also have experienced contamination on days when testing did not occur.
Abby Longo, a clean water advocate of Safe for Swimming campaign with Environment America, said the findings are concerning despite those limitations.
“Having any degree of E. coli contamination or fecal contamination in our waters shouldn't be tolerated,” Longo said. “We ought to be entitled to swim and paddle in our waterways without being concerned about the consequences.”
The report also found that 70% of the monitored locations had potentially unsafe levels of contamination on at least one-quarter of the days they were tested.
The report identified Truman Lake in Benton County, Sycamore Creek in Newton County and Grand Glaize Creek in St. Louis County has waterways with some of the highest combinations of recreational popularity and contamination risk.
Fecal contamination has entered waterways through sewage overflows, stormwater runoff, agricultural manure and failing or inadequate septic systems, according to the report.
Longo said failing or inadequate septic systems, particularly in communities where residents cannot afford to replace or upgrade them, are a major source of fecal contamination.
She said residents can receive assistance through the federal Clean Water State Revolving Fund, but the program is underfunded. The report says Missouri needs about $450 million a year for the next 20 years to improve wastewater and stormwater infrastructure, while Congress has provided about $95 million to the state through one federal funding source.
“Communities in Missouri could really reduce their sewage overflows and other sources of fecal bacteria,” Longo said. “But infrastructure projects like replacing sewer lines or upgrading wastewater treatment plants require pretty substantial resources.”
Longo said swimming and other recreational activities in contaminated water can expose people to pathogens that cause gastrointestinal illness, respiratory infections, ear and eye infections and skin rashes, according to the report.
Centers for Disease Control and Prevention estimates that recreational activities such as swimming, fishing and boating are associated with about 90 million illnesses each year in the United States. Most of those illnesses are likely unreported.
