Doug Kagan, president of Nebraska Taxpayers for Freedom, called the valuation system "a festering sore that never heals."

The preliminary valuations would raise the total valuation of property in Douglas County by 8.25 percent. In some areas of far west Omaha, valuations would increase by over 20 percent. Some homeowners in various parts of the city would see their valuations double or more.

Battiato told the board two factors are driving the increases. She said many properties had not been re-appraised by the Assessor's Office for many years. And she said a hot real estate market has been driving up the market value of homes.

Nebraska law requires county assessors to set property valuations at 92 to 100 percent of market value, and to ensure properties are assessed equally.

Battiato, who took over the Assessors Office in 2015, said she realizes the large increases are shocking to taxpayers. She said her staff will look into the individual issues raised Tuesday. She urged people who believe their valuation is wrong to schedule an appointment to meet with a county appraiser.

Battiato also said she's "considering options" to lessen the impact. She said that included talking with state tax equalization officials.