The Metropolitan Sewer District of Greater Cincinnati (MSD) provides wastewater collection and treatment for residents and businesses in Hamilton County, Ohio and small portions of Butler, Clermont and Warren counties. MSD's service area encompasses 290+ square miles and serves a population of more than 850,000. MSD maintains about 3,000 miles of sanitary and combined sewers and operates seven major wastewater treatment plants, more than 100 pump stations, two package treatment plants and several high-rate treatment facilities. About 180 million gallons of wastewater is treated daily. MSD has a ratepayer base of about 226,000 residential, commercial and industrial customers. Within that base, it monitors about 200 industrial users who discharge pre-treated waste into the sewer system.