Allenstown officials are considering asking voters to approve a $15 million bond for renovations to the sewer treatment plant, which is stalled at maximum capacity.

A state Department of Environmental Services order has prohibited new sewer hookups to the 1975 plant, which serves both Pembroke and Allenstown, for the last 15 months.

If the $15 million plan is approved, Pembroke would absorb 52 percent of the cost of repaying the bond, according to an intermunicipal wastewater services agreement hashed out by sewer commissioners in the neighboring towns.

The $15 million renovation would more than double the plant’s flow capacity, said engineer Michael Trainque, who joined the Allenstown sewer officials in discussing the plan with selectmen at a Monday, Dec. 11, meeting.

Trainque said as much as 60 percent of the renovation costs could be recouped by a combination of federal and state grant money. A worst-case scenario, said Trainque, is only 20 percent of the total cost being recouped by grants.

Pembroke’s share for the cost is based on a demographic study forecasting sewer needs for the next 20 years in the two neighboring towns. The numbers are spelled out in the inter municipal agreement, signed in November after three years of negotiations.

Allenstown Sewer Commission Chairman James Rodger said the commission has been drafting a warrant article for the $15 million bond for this year’s Town Meeting, and asked selectmen for input on whether the cost in Allenstown should be paid by all taxpayers or just the town’s sewer users.

Currently, there are 633 sewer ratepayers in Allenstown. Selectmen said either way the repayment of the bond is structured, such a hefty bond is going to be a tough sell to voters.

“All the people that are on septic, they’re not going to want to pay for this, and it’s going to get defeated,” said selectmen Chairman Sandy McKenney. Later in the meeting, McKenney said, “That’s a lot of money for the ratepayers to pay back.”

Selectman Peter Viar requested sewer officials return with an analysis of how the two repayment structures might impact taxpayers.

“I personally don’t have an opinion until someone crunches the numbers for me,” he said.

Viar, who said he welcomes upgrades to the plant because it could allow for more businesses and associated tax revenue, repeatedly suggested sewer officials will have a difficult public relations campaign on their hands.

“You’ve got a hell of a PR task to make people understand the big picture,” he said.

Selectmen also questioned whether the bond proposal would be ready for this year.

Town attorney Biron Bedard said the town would have to get approval from the governor and executive council to sell the bond, which would exceed the town’s debt limit.

The deadline for public hearings on large bond proposals is Jan. 9, and McKenney questioned whether all the details of the plan could be ironed out before the March Town Meeting.

“It seems like there are a lot of unanswered questions here,” she said.

Officials contacted in Pembroke were reticent about commenting on Allenstown’s plans. Pembroke Sewer Commission Chairman Harold Thompson declined to comment on the record, and sewer commissioner Paulette Malo referred all questions to Thompson.

Pembroke Town Administrator Troy Brown and selectmen Chairman Larry Preston didn’t return calls by press time. Pembroke Finance Director Geoff Ruggles said there are currently no warrant articles addressing potential sewer upgrade costs slated for Pembroke’s 2007 Town Meeting.

“Until we know what the specific costs are going to be, there’s nothing specific for this year’s Town Meeting,” he said. “Pembroke really can’t do anything until Allenstown does approve that bond.”