Potomac Riverkeeper’s 2016 review of Clean Water Act discharge permits on the Potomac led us to the Winters Apartments Sewage Treatment Plant in St. Mary’s County, Maryland, where chronic operational problems were causing frequent permit violations for excessive discharges of ammonia and suspended solids into the Potomac. This pollution threatened public health and degraded the tidal Potomac, and had been going on for months. After trying unsuccessfully to work with the plant owner, the Widener Law School Clinic filed a legal warning letter in May 2016 on our behalf, and notified the Maryland Department of the Environment (MDE). MDE responded by taking its own enforcement action, culminating in a $22,500 penalty and consent order in early 2017 that compelled the plant owner to immediately make repairs and stop polluting the river. This is a powerful example of the role PRK plays in finding polluters and using the Clean Water Act to protect our rivers, in this case by engaging MDE to step in. In light of EPA’s recent actions to rollback environmental protections for our rivers and drinking water, PRK’s role as the public’s watchdog on the river has never been more important.