AMHERST — Average homeowners would pay $18 more in their annual water bills if the Select Board approves a rate adjustment proposed to go into effect July 1.

Town Manager Paul Bockelman issued a memo Jan. 6 showing that the water rate would go up from $3.65 per 100 cubic feet to $3.80 per 100 cubic feet, a 15 cent, or 4.1 percent increase. The increase would support the Water Department’s budget and maintain a fund balance in anticipation of lower water use in the coming years, he said.

With the Select Board in August imposing a mandatory water ban for the first time due to the ongoing drought, Bockelman said Wednesday that his suggested rate increase is needed to ensure there is sufficient money to support operations of the water supply.

The bill for a typical family of four would rise from $438 to $456 annually.

Though Select Board members this week asked about whether graduated rates could be implemented that would make those using larger quantities pay more, Bockelman said there are risks in discouraging water use because the town might not be able to cover the fixed costs of delivering water.

“Costs don’t get lower,” Bockelman said.

The board will decide at its Jan. 23 meeting whether to approve the rate adjustment.

The sewer rate would remain at $3.75 per 100 cubic feet and a $450 bill for an average homeowner, according to the proposal.

The combined water and sewer bills of $906 is less than the $1,103 paid by residents in Hadley and Northampton, where residents pay $1,248, and Belchertown, which assesses $1,489, according to statistics provided by Bockelman.

The operating budget for fiscal 2018, and the enterprise funds for water, sewer, transportation and transfer station, will be unveiled to the Select Board and Finance Committee in a presentation by Bockelman at 4 p.m. Thursday at Town Hall.

Scott Merzbach can be reached at smerzbach@gazettenet.com.