Vermont officials say over 7.1 million gallons of partially treated sewage and rain water was released into Lake Champlain.
The mix of waste and rainwater was released from the Burlington Main Plant starting at 2 p.m. Monday and ending at 3:45 a.m. Tuesday.
The state Department of Environmental Conservation says a faulty valve caused the release. Officials say the water wasn't fully disinfected. Disinfectant was instead redirected to the wrong location.
The valve has been replaced and tested to ensure it works correctly.