MECHANIC FALLS — Property-tax bills should arrive in mailboxes this week, and for most property owners they will be somewhat higher than a year ago.

The Town Council, after meeting last week with Michael O’Donnell, the town’s assessment evaluation agent, set the new rate at $20.40 per $1,000 in property valuation.

While last year’s rate stood at $18.55 per $1,000, O’Donnell advised that it is difficult to directly compare the two tax rates because his firm undertook a property appraisal equalization study of the town’s 1,400 properties.

“The equalization study reduced the town’s overall valuation from $142 million to $136 million, a move that automatically raised the town’s tax rate,” O’Donnell said.

Another complicating factor, O’Donnell said, is that a fairly large number of properties saw a decrease in their valuation, while a relatively few saw an increase.

Residents whose property valuation increased at the same time that the town’s overall valuation decreased, O’Donnell warned, can expect to see a relatively large increase in their tax bills.

Town Manager John Hawley said most residents, even those whose property deceased in value, will see an increase in their property taxes.

“We expected the tax rate would go up about 1.5 mills,” Hawley said. “After seven years of holding taxes flat, it was inevitable.”

Property-tax payments are due in two installments: the first, Oct. 15; and the second, May 15, 2014.