Almost all the water in Dane County goes through the MMSD’s Nine Springs facility. It’s one of the most modern facilities around, drawing a constant stream of visitors from around the world. The facility handles 40 million gallons of wastewater a day. In some ways, it’s a simple system, using gravity and microorganisms to purify the water, without the use of chemical agents. Most of the treated water leaving the plant is pumped through a five-mile underground pipeline and discharged into Badfish Creek, which diverts it around the Madison Lakes.  Some is also sent to Badger Mill Creek in order to balance the amount the District takes from the watershed. Much of it returns to the ecosystem, eventually hitting the Mississippi and winding up in the Gulf of Mexico 45 days after release.