How Is My Drinking Water Treated and Purified?

The MMA receives its primary supply of finished water for resale from the Wilkinsburg – Penn Joint Water Authority (WPJWA) system. Like the majority of water utilities in the U.S., the WPJWA uses a multi-step treatment process at their water treatment plant. River water is pumped from the Allegheny River to the treatment plant and chlorinated. The water is then coagulated (which means the smaller particles in the river water join together by adding chemicals, which encourage this attraction). The water is mixed to ensure that the added chemicals are well blended and reacting with all of the smaller particles. The water is allowed to settle so that the newly joined particles sink by gravity to the bottom of the sedimentation tanks. The sediment is then removed and sent to the Allegheny County Sanitation Authority (ALCOSAN) for treatment. The settled water is then filtered to remove any remaining particles. Chlorine is then again added to prevent the growth of bacteria during transport and storage.

The finished water enters the MMA system through two separate metered connections. By agreement with WPJWA, the  MMA is permitted to withdraw 6.0 million gallons per day (mgd) of monthly average flow and 7.5 mgd of peak daily flow from the above connections. In addition to the primary source of supply, the MMA maintains two emergency interconnections with the Municipal Authority of Westmoreland County (MAWC) system. The MMA maintains four storage tanks to serve as a reserve for fire protection and to maintain adequate water pressure. These tanks have a combined capacity of 13.5 million gallons. The water is then delivered to your home or business through a network of over 165 miles of waterlines varying in size from 4 to 24 inches in diameter. If you desire more information about the quality of the water provided by the MMA, please call the MMA Manager, Joseph Storey or log on to our web site at http:// The MMA Board of Directors meets at 7:00 p.m. on the fourth Monday of the month at 219 Speelman Ln., Monroeville, PA 15146, and these meetings are open to the public. The MMA water system identification number is 5020027.