This year's maximum homeowner's exemption has been set at nearly $10,000 less than last year, the Kootenai County assessor announced on Monday.

The Idaho Tax Commission has calculated the 2012 maximum exemption at $83,974, dropped from last year's $92,040.

"If (property owners) weren't at the maximum, they wouldn't see an impact," said Assessor Mike McDowell, adding that the exemption still applies to 50 percent of a primary home's assessed value and up to one acre of land. "For those whose homeowners exemption was capped at the maximum, they will see a change."

About 75 to 80 percent of property owners in Kootenai County have been at the cap for the last several years, McDowell said.

His reminder of the exemption maximum is timed several days before Kootenai County will mail out property value assessments.

Under state law, the state tax commission adjusts the exemption amount each year, based on the Idaho Housing Price Index.

The slipping maximum reflects a fall in housing prices in 2010 and the second quarter of 2011.

Idaho provides the partial property tax exemption to qualifying homeowners. The exemption can't exceed the maximum value.

The lower maximum this year will increase net taxable value, McDowell said.

That won't necessarily boost property taxes, he noted, reminding that property taxes are based on both property value assessments and the budgets set by local taxing districts.

"The impact could be minimal, or negated, if the budgets are conservative," McDowell said. "But if there are pressures that drive budgets higher, we could see potentially increases."

He recommended residents participate in the taxing districts' budgeting process to possibly limit increases.

State law was amended in 2005 to adjust the exemption maximum according to the housing price index, McDowell stated.

The maximum rose from $50,000 in 2005 to more than $100,000 in the last of the 2000s.

The maximum exemption could always shoot up in the future, he said.

"Maybe the market will turn around, and as it does, the housing price index will reflect the change," McDowell said.