Hamilton County Public Health is telling residents to stay out of the Whitewater River and the Great Miami River downstream after a wastewater treatment plant roughly 50 miles away in Connersville, Indiana, was knocked offline and began releasing untreated municipal water directly into the waterway. The plant remains offline as crews plan repairs, and health officials say the contamination has already made its way toward Hamilton County along the river system that eventually empties into the Ohio River.
According to the Cincinnati Enquirer, Hamilton County Public Health received an alert from the Ohio River Valley Water Sanitation Commission reporting that an unknown amount of untreated municipal water was being released into the Whitewater River, prompting the health department to issue a press release warning residents away from contact with the affected waterways. The discharge stems from recent flooding in the area, which is what forced the Connersville plant offline in the first place.
That flooding was severe. Record levels along the Whitewater River in mid-August inundated Connersville, forcing water rescues and pushing river crests near Alpine to nearly 23 feet, according to FOX19. The floodwaters split the town and submerged local infrastructure, ultimately taking the wastewater treatment plant offline entirely.
Why the Contamination Travels So Fast
The Whitewater River is Indiana's fastest-flowing river, dropping an average of six feet per mile as it runs southeast, according to the Indiana Department of Natural Resources. That steep gradient means untreated wastewater released upstream can travel quickly downstream, which is part of why rapid coordination through interstate bodies matters so much here. The Whitewater River flows into the Ohio River, and the Great Miami River — now also under an avoidance advisory — likewise feeds into the Ohio.
That interstate coordination runs through the Ohio River Valley Water Sanitation Commission, known as ORSANCO, which was established under a multi-state compact in 1948 and operates a network of 17 continuous monitoring stations tracking water quality and coordinating pollution alerts across eight member states, per the Northern Kentucky Tribune. It was ORSANCO's alert that first tipped off Hamilton County Public Health to the Whitewater River discharge.
Health Risks and What to Avoid
Health officials say the recreational water in the affected rivers may be contaminated with E. coli and Cryptosporidium. Swallowing potentially contaminated recreational water may cause nausea, vomiting, diarrhea, and stomach cramps, and the advisory urges residents to avoid direct contact with the Whitewater River and the Great Miami River downstream until conditions improve.
Drinking water is a separate matter from recreational contact, however. Greater Cincinnati Water Works supplies drinking water to more than 1.1 million regional customers, drawing about 88 percent of its supply from the Ohio River, and it maintains continuous monitoring with ORSANCO so it can shut down intakes if upstream river contamination poses a threat, according to the City of Cincinnati.
A Familiar Pattern for Hamilton County
This isn't the first time this summer that Hamilton County residents have been told to stay away from local waterways because of sewage. Just five weeks earlier, Hamilton County Public Health warned against contact with Dry Run Creek in Anderson Township after a raw sewage spill there. And in June, the county issued a river contact advisory for the Great Miami River after an undertreated sewage spill at the Middletown Waste Water Treatment Plant flowed downstream for five days before repairs were made, per Hamilton County Public Health.
The pattern goes back further still. In May 2025, Hamilton County Public Health and Great Parks of Hamilton County prohibited fishing, kayaking, and paddleboarding at Winton Woods Park after a sewage release contaminated Winton Lake. Regional infrastructure investment is underway to address the underlying issue: the Metropolitan Sewer District of Greater Cincinnati is executing Project Groundwork, a multi-billion-dollar initiative aimed at reducing combined sewer overflows into the Great Miami River, Mill Creek, and the Ohio River.
Summer Recreation Season Takes a Hit
The timing stings for a river system that draws heavy recreational traffic each summer. Commercial liveries and campgrounds along the Whitewater River, including outfitters in Brookville and Harrison, drive substantial eco-tourism as a popular paddling destination, per Franklin County Tourism. How long repair work at the Connersville plant will take, and how long the downstream advisories will remain in effect, is not yet known — a lingering question during what is typically peak season for river recreation in the region.
