Madison, Wis., May 18, 2026 — Clean Lakes Alliance, in partnership with Public Health Madison & Dane County, is launching a pilot study to better understand elevated E. coli levels that frequently lead to beach closures across the Yahara chain of lakes.
Supported by funding from Dane County and the City of Madison, the initiative will expand beach testing protocols at four sites: Spring Harbor Beach on Lake Mendota, Olbrich Beach and Esther Beach on Lake Monona, and Vilas Beach on Lake Wingra. These locations were selected based on several factors, including a history of high E. coli levels and frequent closures.
The pilot introduces a more targeted testing approach, collecting additional water samples following rainfall events — conditions known to increase bacterial contamination due to stormwater runoff. By focusing on these high-risk periods, in addition to current routine testing, this pilot aims to better understand when and why bacteria levels spike.
“Access to clean, safe beaches is fundamental to quality of life in our region,” said James Tye, Executive Director of Clean Lakes Alliance. “When beaches close, it’s more than an inconvenience. It’s a signal that we need better data and smarter solutions. This partnership allows us to pinpoint the sources of contamination so we can take meaningful, targeted action to
keep our lakes open and safe for everyone.”
Findings from the pilot will inform future strategies to reduce contamination and improve beach safety, aligning with Clean Lakes Alliance’s Renew the Blue stakeholder guide, which outlines key actions to improve water quality throughout the Yahara Watershed.
“This effort is about moving from reactive closures to proactive solutions,” said Brandon Macomber, Environmental Health Services Supervisor at Public Health Madison & Dane County. “By better understanding the drivers of E. coli contamination, we can protect public health and make more informed decisions for our community.”
The pilot will run throughout the summer of 2026, with results helping guide long-term investments in water quality improvements across the region.
