MONTAGUE — The town will receive a $94,668 bill in overage charges from Erving, which processes sewage for Millers Falls, after historic rainfall in 2023 resulted in rainwater infiltrating the processing system.

“It was expected, but this much over was shocking to me,” Chelsey Little, superintendent of the Montague Clean Water Facility, informed the Selectboard during a recent meeting.

Montague and Erving are entering their last year of a 10-year contract whereby the village of Millers Falls has its sewage processed by one of Erving’s three publicly owned wastewater facilities.

“We have something of a symbiotic relationship,” Montague Town Administrator Steve Ellis explained during the meeting. “They don’t have enough total flow to operate a plant without what comes from Millers Falls.”

Montague pays a negotiated amount for the sewage to be processed and for every 1,000 gallons over that amount, the town pays an overage fee. That fee is currently $17.03 per 1,000 gallons. Montague budgets $55,000 for overage fees every year, so a $94,668 bill leaves the town nearly $40,000 short.

“Some years we have gone over and some years we have not used it at all,” Ellis elaborated in a phone interview.

Overage fees are influenced by the amount of rainfall due to inflow and infiltration issues, also known as I and I. Many wastewater treatment systems are designed to collect as little rainwater as possible to limit the amount of unnecessary processing. However, water more frequently infiltrates older systems.

According to Little, Montague had 5.5 million gallons of sewage overflow in 2023 as a result of the summer’s heavy rainfall. The previous year, amid droughts, Montague did not incur any overage fees, Ellis said.

The Department of Public Works has identified two obvious sources of rainwater infiltration using a robotic pipe inspection camera. The DPW hopes to close those infiltration points soon to fix regulatory issues and save money for the town. The department also plans to ask for $30,000 at the spring Annual Town Meeting to pay to line manholes with epoxy to help mitigate these inflow and infiltration issues.

Montague’s current sewage processing agreement with Erving is set to expire in August. Ellis said the towns have not begun negotiations for a new contract yet but they hope to enter into another 10-year agreement.

Reach Bella Levavi at 413-930-4579 or blevavi@recorder.com.