The original 1908 wastewater treatment plant cost $10,727 and had a daily capacity of 400,000 gallons. It was located between the St. Marys River and the Miami and Erie Canal north of the present day Kuck's Cove play area. Treatment consisted of two septic tanks, one dosing chamber, six sand filters, and one sludge drying bed. A sewage pump station and a complete sanitary sewer system were included in the project. Total project cost was $101,210.

1948 & 1969

In 1948, a new treatment plant started operation across the river from the original plant. The new plant utilized primary and secondary (activated sludge preceded by roughing filters) treatment and anaerobic digestion. It had an 800,000 gallon per day capacity and cost $316,000. An addition, completed in 1969, increased daily capacity to 2,000,000 gallons and cost $681,000.


The Northwest Trunk Sewer Project was completed which serves the west portion of the City, including Villa Nova. Two new pump stations also were built.


A project to address high wet weather flows, completed in 1989, cost $3,284,000. The original 1908 pump station was replaced and the two 1960 station were remodeled, increasing capacity. The project included building a 2,700,000 gallon retention basin to store excess storm water, laboratory improvements, a process monitoring system, and emergency generators. Treatment capacity was not increased.

1991 & 1992

The Grand Lake St. Marys Southeast Sewer District and the Sandy Beach Sewer District, both constructed and operated by Auglaize County, were built. St. Marys treats the wastewater.


The Northeast Sewer Improvement Project included a new gravity sewer to serve McKinley Road and construction of the Northeast pump station to pump directly to the treatment plant.


The Northeast Relief Sewer Project diverted all flows in the northeast portion of St.Marys to the Northeast pump station. A mechanical and electrical upgrade of the station was included. The project provided additional capacity at the New York Central pump station, part of a larger plan to address storm water flows.


A new treatment plant at the site of the existing facility increased daily treatment capacity to 3,000,000 gallons, with a daily peak capacity of 9,000,000. Cost was $11,012,020.


For the first time, wastewater services were extended north of U.S. Route 33, initially to serve the new High/Middle School complex, but sized to serve a much larger area. The project included gravity sewers, force mains, and a pump station.


The Southwest Pump Station project included construction of a second pump station near West School that handles all flows from Auglaize County-owned sewer systems around Grand Lake St. Marys, pumping them directly to the wastewater treatment plant. The existing pump station near West School was converted to handle only those flows from within City limits. A very unique feature of the project is that both pump stations are able to serve as a back-up to the other. Total project cost was $1,536,989 ($1,065,470 for pump station, $471,519 for force main).