Minnesota local governments are increasingly worried about challenges to property tax values they had no role in setting that could cost them tens of millions of dollars.
The largest and most public of the overvaluation claims, Enbridge's appeal of its pipeline property tax bills, alone could force northern Minnesota counties and cities to fork over $45 million in refunds while significantly eroding their future tax base.
The Enbridge case is one of 62 challenges filed in Minnesota Tax Court by pipeline and utility companies over the past six years. The tax court ruled in Enbridge's favor in 2018 and just last month sided with another large pipeline operator in a decision that could force a $17 million refund.
"What started out as a wave has turned into a tsunami," said Matthew Hilgart, government relations director for the Association of Minnesota Counties. "You don't budget for this sort of thing."

Pipeline and utility property tax appeals that don't reach tax court can also become an issue with local governments. Last year, Xcel Energy, the state's largest property tax payer, won a 7 to 8 percent reduction in its valuation through an in-house appeals system at the Minnesota Department of Revenue.
Xcel's case involved no tax refunds, but it's likely to affect budgets of counties and cities hosting its larger power plants.
The Revenue Department assesses utilities, pipelines and railroads. Tax money is then parceled out to host counties, cities and school districts. The state also gets a piece of that revenue. Such centralized state assessment is common nationally for sprawling assets like pipelines.
From 2005 through 2012, Minnesota utilities and pipeline operators annually took only two to three disputes with the Revenue Department to state tax court, according to a study by the Minnesota Center for Fiscal Excellence, a nonpartisan tax policy group.