Madison Metropolitan Sewerage District reports sanitary sewer overflow at Nine Springs

Madison Metropolitan Sewerage District has reported a sanitary sewer overflow (SSO) linked to a cracked pipe near the Nine Springs Wastewater Treatment Plant. The failure, located in a district-owned wetland adjacent to the Capital Springs State Trail, went undetected for several days due to heavy rains that increased inflow and infiltration.

The District estimates about 6 million gallons of untreated wastewater were released between August 13 and August 22, with some flow entering Nine Springs Creek. A trail user first alerted staff to unusual activity in the wetland on August 22, prompting an immediate response. A temporary repair was completed by August 23, and the trail has since reopened.

District staff took several steps to limit environmental and public health impacts, including diverting wastewater from the damaged pipe, blocking creek flow, pumping contaminated water back to the treatment plant, and implementing daily water quality sampling. Regulators at the Wisconsin DNR and Public Health Madison Dane County were notified per permit requirements.

“While no system can anticipate every scenario, we can be prepared and accountable for how we respond,” said Executive Director Eric Dundee in a press release. “Our team, equipped with strong maintenance and inspection practices and emergency response training, immediately activated our response plan, notified our public health and environmental regulators, and took the steps needed to reduce impacts.”

The District is coordinating with regulators on follow-up actions and plans to complete a permanent repair in the coming months.