Council approves five‑year interlocal wastewater agreement with Mantua (Manaway) City; new connections to pay full Brigham City sewer impact fee

Brigham City adopted a five‑year interlocal agreement Thursday to continue treating wastewater from the nearby town of Mantua (referred to in city materials as "Manaway"), closing out an older, expired contract and updating financial, capacity and compliance terms.

City Administrator Derek Oiler told the council the prior agreement had allowed Mantua customers to pay 80% of the Brigham City residential sewer charge; under the new contract Mantua customers will pay the same monthly rates as Brigham City customers. The new agreement also requires new connections in Mantua to pay a connection fee equal to Brigham City’s sewer impact fee at the time of connection.

The agreement contains several key operational terms: Mantua remains responsible for collection system maintenance up to the interconnection point; Brigham City will meter flows where the two systems connect; Mantua must address infiltration and inflow problems causing elevated flows and has a transition window in which the city will assess modest overage fees if infiltration pushes the per‑dwelling monthly average above a defined threshold.

Details the council heard

- Overages and infiltration: The agreement sets an overage rate of $2 per 1,000 gallons for flows above a residential threshold that staff modeled from state averages (staff described a roughly 360–400 gallons per dwelling per month baseline). Mantua’s flow has intermittently exceeded that threshold during some months; staff and Mantua officials have been exchanging data and Mantua is undertaking system repairs.

- Prior plant upgrade cost sharing: Oiler said Brigham City previously made required plant upgrades on state‑mandated nitrogen/phosphorus compliance projects; under the old arrangement Mantua’s share for a multi‑million‑dollar upgrade was small (about $160,000 on a $6–8 million project), and the new connection fee structure is intended to capture future growth‑related costs directly from new development.

- Capacity limit: The contract establishes a maximum allowable flow into Brigham City's system at the current pipe capacity in the canyon; staff said that figure should not be reached during the five‑year term given available developable land.

Council action

Councilmember Smith moved to approve the resolution authorizing the interlocal agreement; Councilmember Jensen seconded. The council adopted the resolution on roll call vote.

Why it matters: The updated contract resets financial expectations for Mantua connections, places the capital‑expansion risk for major plant upgrades on Brigham City (while charging new Mantua connections the same impact fee as Brigham City), and seeks to limit infiltration through scaffolded overage charges and a compliance timetable.

Next steps

Staff will implement a metering arrangement at the interconnection, monitor Mantua infiltration reductions, and apply the new connection fee for future Mantua development if and when developers seek to connect. The agreement runs five years and will be revisited with changing development patterns and system performance.