Dayton draws its drinking water from a buried valley aquifer that also sits under Wright-Patterson Air Force Base. Decades of firefighting foam use put PFAS into it. The city is now doing two things about that at once: building the largest dedicated PFAS removal facility in the country, and suing the Defense Department to pay for it.
The city hired Shook Construction, a Dayton firm, as construction manager at risk on the $350 million project at its Ottawa Water Treatment Plant. Black & Veatch and Tetra Tech are the design consultants, with Tetra Tech’s scope estimated at $200 million.
Retrofitting a 70-year-old plant that can’t stop running
Ottawa produces 96 million gallons a day and it’s roughly seventy years old. The scope is an ion exchange PFAS removal facility plus a full plant retrofit, and it has to be built while the plant keeps delivering water to the city. Construction starts this year, the PFAS facility is complete in 2029, and the retrofit finishes in 2031.
PFAS at the plant currently runs three to four times the future federal limits. EPA’s April 2024 rule set maximum contaminant levels of 4.0 parts per trillion for PFOA and PFOS and 10 ppt for PFHxS, PFNA and HFPO-DA, with the compliance period extended in May 2026. Dayton has already spent $14 million on PFAS reduction before this project.
Why CMAR, and why it’s becoming the default
Both the treatment technology and the regulatory target are still moving. Resin selection, vessel sizing, spent media handling and the eventual disposal path are all subject to change between design and startup, and hard-bidding that is a good way to buy a change order program. CMAR lets the builder price it in packages as the design settles, and lets the city stop the work if the rule shifts again.
Water and wastewater owners have been moving this direction for years on complex retrofits. Comparable modernization work at plants like the Kansas River Wastewater Treatment Plant runs into the same constraint: you’re rebuilding a process train that cannot go offline.
The litigation is the funding strategy
Dayton sued Wright-Patterson and the Defense Department in March 2026 seeking more than $300 million. The Air Force says it has invested over $63 million since 2014 across 26 sites at the base.
That’s the part water contractors should watch. A city of Dayton’s size cannot fund a $350 million treatment project on its rate base without a painful rate case. A city that can pin the cost on DOD or on a chemical manufacturer can build something several times larger than its ratepayers would ever approve. PFAS remediation is turning into a well-funded market segment, and the funding is coming from courtrooms as much as from bond issues. Track the settlements, then track the procurements that follow them.
Background on the suit: WYSO.