Residents could be forced to repay up to 11.6 million in disputed taxes to utilities, if the Idaho Supreme Court backs a power company’s contention that state appraisers improperly inflated the value of the company’s property.

Justices could issue a ruling soon in the case pitting Idaho’s Tax Commission against Rocky Mountain Power-parent PacifiCorp.

PacifiCorp won in 4th District Court in Boise in a dispute over its 2008 appraisal.

The Tax Commission has appealed.

The justices’ ruling could have broader impacts for taxpayers than just those in Rocky Mountain Power’s southeastern Idaho service territory.

That’s because IdaCorp Inc. unit Idaho Power, the state’s largest utility, also has appealed recent appraisals, too.

And the court’s decision could set a precedent for other businesses like railroads, telecommunications companies and publicly-regulated water utilities with operating properties.