History:

West Mifflin is a historic Pennsylvania community with deep roots dating back to the formation of Allegheny County in 1788. Home to more than 20,000 residents, the borough is named for Governor Thomas Mifflin,Pennsylvania’s first elected governor and a signer of the United States Constitution.

Originally established as Mifflin Township, the area played an important role in early American history and regional development along the Monongahela River. In 1944, West Mifflin became the first township in Pennsylvania to incorporate in its entirety as a borough—marking a significant milestone in local governance.

Today, West Mifflin Borough stretches over 14 square miles and is a primarily residential community that also supports major employers, transportation hubs, and regional attractions such as Kennywood Park, Bettis Atomic Power Laboratory, US Steel's Mon Valley Works–Irvin Plant, and the Allegheny County Airport. As the community has grown, so has the need for reliable, environmentally responsible wastewater and stormwater infrastructure.

The West Mifflin Sanitary Sewer & Stormwater Authority supports this legacy by protecting public health, preserving local waterways, and maintaining essential sewer and stormwater systems that serve residents, businesses, and future generations.