Officials with Clarksville Gas and Water say the waste water that occasionally overflows into the Cumberland River is well within the boundaries of Environmental Protection Agency regulations. When Clarksville is inundated with rain, the city's combined storm water and sewage system can get backed up, forcing some of the untreated contents into the Cumberland River. Officials say that happens several times a year, on average, but only after significant rainfall. The issue is blamed on the city's ancient infrastructure, with part of the sewage system downtown dating back more than 100 years. "And what happens, when those pipes go under a surge condition, it backs up into this facility," said Brian Goodwin, chief utility engineer for Clarksville Gas and Water. When the system gets overwhelmed, waste and storm water backs up into the city's two combined system overflows (CSO). The combined waste and storm water is partially treated at the CSO, before being released into the Cumberland River. Those contents are piped into the river about 15 feet under the water. Residents told Nashville's News 2 that something should be done to avoid having to dump waste into the river. "That's very unsanitary for one thing," said resident Michael Taylor. "It's real nice out here. People fish and possibly even want to get into that water. That's very nasty."Goodwin says those discharges are permitted by the EPA. Clarksville Gas and Water is also required to monitor and record how much waste and storm water is discharge. Officials with Gas and Water say those discharges into the river can vary from a few hundred gallons to tens of thousands of gallons of waste, depending on the amount of rainfall. Metro-Nashville also operates a combined sewage and storm water system. Metro has agreed to an EPA request to make upgrades to the system to prevent further overflows into the Cumberland River and its tributaries.