As the weather heats up and Rochester residents flock to Lake Ontario for a swim, environmental experts urge caution after heavy rainfall.
Rochester’s combined sewer system handles both stormwater and wastewater, funneling it all through the same pipes to the county’s treatment plant. But when a big storm hits, that system can overflow, sending untreated sewage and runoff directly into local waterways.
Karen Berger, an associate professor in Earth and Environmental Sciences at the University of Rochester, said these overflow events are becoming more common.
“As air warms, it can hold more moisture,” she said. “So with about every degree, we get about 7% increase in how much moisture the air can hold, which means when the rain does happen, there is more moisture in the air that can fall as rainfall.”
That runoff can carry bacteria like E. coli, as well as fertilizer and animal waste — all of which can pose health risks for swimmers. While Monroe County has made major improvements to reduce overflows, Berger said it’s still smart to avoid swimming for up to 48 hours after a heavy rain.
The county monitors water quality daily at Ontario Beach Park and updates a hotline — 585-753-5887 — with the latest safety information. Beaches managed by the state, like Hamlin and Stony Brook, have their own testing systems in place.
According to the county’s website, whether the beach is open “depends upon five parameters to determine if the beach will be safe for swimming: water clarity, organic debris, local rainfall, fecal coliform bacteria levels, and Genesee River flow.”
