GARDINER — The city is considering changing its sewer billing practices to charge based more on a property’s actual sewer use, instead of estimates based on its possible demand on the sewer system.

City Manager Scott Morelli said some sewer users feel the current model places a disproportionate burden on certain properties, like churches and social halls, that use little water despite their size.

However, Morelli said, the current model does allow the city’s heaviest residential and commercial users to pay more modest sewer bills.

If the formula for determining sewer usage is changed, the annual bill for the Maine Turnpike Authority’s rest area and visitor center in West Gardiner could jump from $1,955 to $5,080.

On the other hand, several churches could see a decrease in their bills. For example, South Gardiner Baptist Church could pay $85 a year instead of its current bill of $307.

Chuck Applebee, Gardiner’s wastewater and public works director, said the current system — called an equivalent user-rate-base formula, or EUR — was designed to help the city recoup its costs and maintain the wastewater system’s fixed costs.

If the new system is adopted, Morelli said each sewer user in Gardiner would pay a base rate of $87 per quarter, which would cover up to 1,200 cubic feet of wastewater discharged into the sewer system.

Heavier users would then be billed an additional $10 for each 100 cubic feet of wastewater above the 1,200 cubic foot minimum.

“The city felt it was important that everyone be given advance notice of this possible change so that they could have their voice heard, either for or against the proposed change,” Morelli said Thursday. Morelli noted this plan is not a rate increase. Both the current and proposed scenarios are intended to raise a similar amount of revenue. Sewer billing in Gardiner is $1,052,427 for 2010-2011.

Morelli said the proposed formula would simply shift more responsibility onto those who contribute more to the sewer system, as opposed to those who could potentially do so, which is the basis of the current EUR formula.

Under the current system, if a building had the potential to contribute one-tenth of a percent of the city’s wastewater, but only contributed 1/50 of a percent, the owner would still be billed as if they were contributing the higher amount of wastewater.

“So the question the council will be considering is whether to continue to charge users based more closely on their potential use or whether to charge users more closely based on their actual use,” he said.

The Gardiner City Council will hold a public hearing on the proposed rate change at 7 p.m. on Wednesday, Dec. 7, at City Hall.

Those unable to attend can post their comments before the meeting via mail or email at info@gardinermaine.com.

Morelli said officials expect a significant turnout at the public hearing.

Mechele Cooper — 621-5663

mcooper@centralmaine.com