LISBON – Due to a calculation error, Lisbon taxpayers will get a pleasant surprise next week: a new, lower property tax bill.

The bills sent out this week incorrectly listed the town’s 2008-2009 property tax rate at $26.65 per $1,000 valuation. The correct rate is $25.50.

The $1.15 difference means a home valued at $100,000 will see a new annual tax bill that’s about $115 lower.

Town Manager Stephen Eldridge blamed the difference on a calculation error.

“People make mistakes,” he said.

While tax bill errors are unusual in Maine’s 489 towns and cities, they do happen once or twice a year on average, according to Maine Revenue Services.

Lisbon’s corrected tax bills will be sent Sept. 5.

Taxpayers who have already paid the higher bill have two options: request a refund or request a credit on the next semiannual tax bill, which will be sent in March. Taxpayers must see tax collector Nancy Bosse to make their choice.

For taxpayers who have not paid the higher tax bill, the due date has been extended from Sept. 15 to Sept. 30. There will be no penalties or interest changes for payments made after Sept. 15.

Lisbon has about 4,500 taxpayers. The town outsourced its tax billing this year.