 EPA and municipalities have tried really hard to reduce the number of times that that happens, and they've done a great job over the years, but there's still rain events that can flush the system and move some of that wastewater to the environment without any treatment. Around 30 communities in Maine still use combined sewer systems. And you're listening to All Things Considered on Maine Public Radio. I'm Robbie Feinberg. It's five minutes after five o'clock.