The Jonesville Wastewater Treatment Plant has notified state and local water officials of a release of between 500 and 1,000 gallons of partially treated sewage.
The release occurred between 4 a.m. and 6 a.m. Wednesday, as the result of an equipment failure.
A portion of the treated sewage may have reached the St. Joseph River through a storm drain.
The equipment failure has been addressed and the plant has been operating normally since 8:30 a.m. Wednesday.