Clean Water 35 (Phase 2B): Building a stronger sewer system for the next generation
Cleaner waterways. A more resilient and modern sewer system. Better value for Cincinnati.
Clean Water 35 is the next phase of MSD's multi-billion-dollar and multi-decade Wet Weather Program. It not only supports MSD's mandate to reduce sewer overflows, it brings lasting public benefits of more dependable sewer infrastructure, modern technology, and responsible stewardship of ratepayer money.
Clean Water 35 will:
- Move more water - Increase the capacity of the existing sewer system to convey wastewater flows to a treatment plant
- Treat more water - Improve the treatment capacity of existing plants and build new high-rate treatment facilities to treat more wastewater
- Keep rainwater out- Find ways to keep rainwater out of the combined sewer system, like partnering with ODOT on conveying stormwater from I-75
- Make the system smarter and more resilient- Replace outdated infrastructure and processes with modern assets and new technology that will last for generations.
To date, MSD's Wet Weather Program has eliminated 8.1 billion gallons of combined sewer overflows (CSOs) a year through the implementation of more than 180 wet weather projects. Clean Water 35 (Phase 2B) is the fourth phase and is anticipated to reduce combined sewer overflows (CSOs) by an additional 1.5 billion gallons in a typical year of rain.
OVERVIEW OF CLEAN WATER 35 (PHASE 2B)
Clean Water 35 (Phase 2B) includes the construction of six projects over an 11-year period between January 1, 2025, and December 31, 2035. The plan is anticipated to achieve a 1.5-billion-gallon reduction in CSOs during a typical year. This phase was approved by the U.S. EPA in July 2025, VIEW THE APPROVAL LETTER AND SCHEDULE
The Clean Water 35 projects include:
Mill Creek Bundle:
- Mill Creek WWTP High Rate Treatment Pump Station: New 700 million gallon per day (MGD) pump station to pump wastewater into the Mill Creek treatment plant and ultimately to a a new high-rate treatment facility. The new pump station replaces the existing 430 MGD station built in 1959. This project is currently in construction. VIEW MILL CREEK PUMP STATION PROJECT
- East Branch Ohio River Interceptor Extension (EBORIE) in Queensgate: Construction of new storm sewers to convey stormwater from I-75 to the Ohio River/Mill Creek as part of the Ohio Department of Transportation (ODOT) Brent Spence Bridge project. ODOT is reimbursing all MSD construction costs. This project is currently in construction. VIEW EBORIE PROJECT
- Mill Creek WWTP Dewatering Building Improvements: New dewatering building with odor control for solids processing.This project is currently in planning. VIEW DEWATERING PROJECT
Little Miami Bundle:
- Little Miami WWTP Solids Disposal with Odor Control: Construction of an anaerobic digestion facility to convert waste solids into biogas and biosolids for beneficial reuse. Also upgrades to existing solids processing facilities, including odor control. This project is currently in construction. VIEW ANAEROBIC DIGESTER PROJECT PAGE
- Little Miami WWTP Electrical, Primary, and Secondary Improvements: Upgrades at primary and secondary treatment to support increased wet-weather treatment capacity from 55 MGD to 100 MGD through secondary treatment; also replacement of electrical equipment that is beyond its useful life. This project is currently in design. VIEW LITTLE MIAMI EPS PROJECT
- Little Miami WWTP High-Rate Treatment (HRT) Facility: Construction of an HRT with a treatment capacity of 115 MGD during wet weather. Also upgrades to existing plant influent pumping and screening systems and disinfection. This will eliminate the bypass of wet weather flows at the plant during a typical year. This project is currently in planning. VIEW LITTLE MIAMI HRT PROJECT
