MILWAUKEE -- Taxpayers say the assessed values of their homes should be going down like housing prices, but city assessors say it's hard to keep up with a changing market.

A recent look at a sample house in Milwaukee showed the assessed value was 25 percent more than the value listed in the online real estate database Zillow.com.

Another look at the assessed value of a home for sale in West Allis showed an even bigger discrepancy between the assessed value used to calculate the property taxes and what the home is really worth to a buyer.

Real Estate Broker Peter M. Stefaniak says the difference is about $40,000.

He says when the owner approached him to sell this home, he quickly realized the city's tax bill showing the home's value of $111,000 was way off the realistic price in today's falling market.

"There's are a lot of homes similar in West Allis that were a product of a foreclosure or short sale," explained Stefaniak.

So he priced the home at $79,000.

"So many sellers say, Why should I price it less than what the city says it is worth? I try to explain to them, the city is determining a value to tax you on. A house is worth what a buyer is willing to pay for it," noted Stefaniak.

A few months after putting up the house for sale, he says the owner accepted an offer for about 35 percent less than the assessed value.

Some say values are not in line with current prices because the cost of doing assessments is slowing the process.

"Here in West Allis we do a complete re-evaluation every two to three years," said Chuck Ruud, West Allis Assessor.

He says homeowners can appeal an assessment and may get the value lowered, which could bring down their taxes.

Appraiser Dan Schley warns that homeowners may "spend some money trying to go to the board of review" for an appeal. Some hire appraisers and lawyers.

He says few go through the appeal process after learning many assessments are too high.

"They're all about equally wrong. If assessments are all equally wrong, you're still paying your fair share," explained Schley.

But that doesn't ease the frustration of homeowners paying their property taxes and questioning their assessment.

"It went down just a little bit, but it's still extremely high, and the taxes is outrageous," said Shirley Thames, who added that she appealed her assessment but got nowhere.

"We just heard back from them, and they said they'd do what they could. But they didn't really do anything. They came out and looked at the house and everything and said it was fair," said Thames.

She is one of hundreds of Milwaukee residents who appeal the assessed value of their home every year in a city that spends the money to re-evaluate property annually to try to keep up with a changing market.

"Many people do feel their home is over-assessed, but we must rememer the assessment that shows up on the tax bill is already a year old," said Milwaukee's chief assessor Peter Weissenfluh.

An attorney representing several clients appealing assessments says the best approach is call your local assessor before assessments are done in the spring to help them get the value right and avoid the hassle and cost of an appeal.

If you've got an issue you'd like us to investigate, send us an e-mail to dmoca@cbs58.com.