Greater Cincinnati Water Works supplies water from two sources.

• The Miller Treatment Plant treats surface water from the Ohio River and supplies 88% of drinking water to GCWW's customers, including most of the City of Cincinnati.
• The Bolton Treatment Plant treats groundwater from ten wells in the Great Miami Aquifer. It is located in southern Butler County. Our aquifer (buried sand and gravel filled with water) is 150-200 feet deep and two miles wide. Bolton Plant supplies about 12% of GCWW water.

To find where your water comes from, look at the map showing areas served by the Miller Plant on the Ohio River and the Bolton Plant on the Great Miami Aquifer.* ( printer-friendly map with lists of neighborhoods served)

* Water from the Miller and Bolton Plants is delivered to customers in an open distribution system, which means it is mixed in the water mains.  The border on the map above is the dividing line under most conditions, although water from either plant may go miles beyond this border.