The Chicago River is largely toilet water, so it would stand to reason that playing in it could make you sick. But according to a long-awaited health study published Wednesday, boating and fishing on the river is no riskier than doing so on other local waterways

Researchers at the University of Illinois at Chicago say those activities do raise the risk of gastrointestinal disease. But the rate, about 14 cases per thousand people, is nearly the same as for waterways considered clean enough to swim in, such as the Fox River, Crystal Lake and Lake Michigan.

“[The Chicago River] is wastewater that’s been treated but not disinfected,” says Sam Dorevitch, associate professor in the UIC School of Public Health and lead author of the study. “So I assumed that we would wind up seeing higher rates of illness among Chicago River users, but that was not the case.”

It is possible that people simply take more precautions on the Chicago River.

“The people that are on the Chicago River are really actually quite careful,” says Margaret Frisbie, executive director of Friends of the Chicago River. “And so our take on it is that while the study seems to show that these swimmable places are the same risk as the Chicago River, that really people are interacting with the waterway in different ways.”

The UIC study, known as the Chicago Health, Environmental Exposure and Recreation Study, or CHEERS, is based on interviews with more than 11,000 people who recreate either on the Chicago Area Waterways System, other nearby waterways or on dry land.

The researchers did find a higher rate of eye irritation in Chicago River users. The Metropolitan Water Reclamation District, which funded the study, has begun moving toward disinfecting the river.