The next time you’re outside, take a minute to look at the street in front of your house. If you live in town, the metal storm drain by your house carries water from the road to your city’s storm drain system. As Minnesota communities paved their streets in the early 1900s, they also installed sewer systems, now called “storm sewer systems” to drain the rain that used to turn streets into lakes. Initially both household sewage from bathrooms and street rain runoff ran through these underground pipes to a nearby river or lake. But raw sewage can pollute area waterways.