Combined sewer overflow mitigated
to meet Ohio EPA mandate

Location:
Norwalk, OH
Installation Date:
2025

Owner:
City of Norwalk

Engineer:
American Structurepoint

Contractor:
Underground Utilities Inc
Norwalk Ohio Sanitary Sewer
As part of a mandate by the Ohio Environmental Protection Agency (OEPA), the City of Norwalk had to address its last two remaining combined sewer overflows (CSO). The elimination of the CSOs, which is one of the city’s largest projects in recent history, will rid the city and its residents of backups during major flooding events.

PRODUCTS USED

During those flooding events, the sanitary sewers would back up into residences and also flow directly into streams, rivers and their tributaries. 

To eliminate the backups, large diameter, triple-wall SaniTite HP, a polypropylene pipe, was chosen over traditional pipe types. 8,300’ (2,530 m) of 48” (1200 mm) and 1,000’ (305 m) of SaniTite HP was used for the main trunk lines. 

Triple wall SaniTite HP has a smooth interior and exterior wall with corrugations in between. It is made from polypropylene for extra pipe stiffness and has dual gaskets for joint integrity. Polypropylene is ideal for sanitary applications as it is an inert material resistant to chemicals, abrasions, hot soils and caustic effluent. The light weight of the product provides the best installed cost.