The Allegheny County Sanitary Authority hosted its 24th annual Open House on Saturday, September 19, 2026, celebrating 80 years of service with close to 2,000 people at the plant.

New this year, ALCOSAN debuted a 2,000-gallon river-water fish tank, giving visitors a close-up look at the variety of fish in our local waterways. Guests also explored eight decades of ALCOSAN history through videos, photos, and artifacts in the new “80 Years of ALCOSAN” exhibit.

“For 80 years, ALCOSAN has been part of the fabric of our region, with a shared commitment to protecting our waterways,” said Arletta Scott Williams, ALCOSAN’s executive director. “Open House is one of our favorite opportunities to welcome our community, share the work we do and introduce them to the dedicated people who make it all possible.”

Guests went behind the scenes on tours, participated in hands-on activities, and met ALCOSAN staff throughout the day. Highlights included:

• Plant and Laboratory Tours: Visitors walked through the expanding wastewater treatment plant and state-of-the-art laboratory, learning about the wastewater treatment process.
• The Clean Water Zone: Families followed Frankie’s fin prints to interactive activities exploring how ALCOSAN works to “Move It, Hold It, Remove It and Treat It” through its Clean Water Plan.
• Frankie the Fish: ALCOSAN’s favorite mascot greeted visitors and posed for photos throughout the day.

The rain-or-shine event was free and open to the public, with complimentary parking and lunch. For more information about ALCOSAN and its community programs, visit alcosan.org.