HATFIELD — Water and sewer rate changes for the second half of the fiscal year, if approved by the Select Board, could add about $15 to the monthly bill for the typical single-family household.

A hearing on the proposed rate adjustments, and the possibility that the combined annual payments for a homeowner will rise from $1,260 to $1,440, will be held Dec. 3 at 5:45 p.m. at Memorial Town Hall.

David Prickett, president of DPC Engineering LLC of Longmeadow, told the Select Board last week that the combined enterprise fund for sewer and water has been on a rollercoaster. But there is a need to have enough revenue to cover the debt service from the nearly $13.5 million wastewater treatment plant overhaul and assorted water system upgrades, including several capital projects, such as the extension along Routes 5 and 10.

“There’s been a lot of changes in the system, and on top of that I think it’s fair to say there’s been accounting changes over the last couple of years,” Prickett said.

Without the rate changes, the combined $1.2 million enterprise funds could be running a deficit. There is also a need to avoid a steep increase in fiscal year 2026, when the town begins paying the debt on the wastewater treatment plant, and to have sufficient money in retained earnings, which is the piggy bank for the water and sewer systems.

With a $1.2 million combined budget between the enterprise funds, Prickett said the idea is to have about 60% of the operating budget in reserves, which by the end of fiscal year 2026 could total between $900,00 and $950,000.

“It’s good that in the event of something unexpected, you have enough reserves to deal with it,” Prickett said.

Under the proposal, the monthly sewer bill for a typical household, with four residents, would go up from $64 to $74, and the monthly water bill for these same households would rise from $41 to $46.

For sewer, the current $11.96 rate per 100 cubic feet would go up by 16% to $13.87 per 100 cubic feet, and for water, the $6.31 rate per 100 cubic feet would climb by 12% to $7.07 per 100 cubic feet.

Prickett’s presentation also shows potential for another 8% sewer rate increase in fiscal year 2026, to $14.98 per 100 cubic feet, and the possibility of another 6% water rate increase in fiscal year 2026 to $7.49 per 100 cubic feet. These are tentative, he said.

Two years ago, the board set the rates for a three-year period as a way to get out ahead of the need for additional revenue and to make itself competitive for a U.S. Department of Agriculture Rural Development grant for the wastewater plant improvements.

Select Board Chairwoman Diana Szynal said the bunching of increase on the spring water and sewer bills, rather than having some of it hit the fall bills, is problematic, though she noted the numbers are more favorable than earlier projections.

“I’m still not happy that we didn’t do this in time that it could be spread over the two bills,” Szynal said.

Szynal said it’s not fair to residents to put all increases on one bill.

Board member Ed Jaworski said he had been worried that the spike would be even sharper. “It’s high, but it’s lower than I was afraid of,” Jaworski said.

Prickett said what Hatfield is facing is not dissimilar from other communities.

“In this business, there hasn’t been a lot of good news for you or other clients,” Prickett said.

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