Values have gone up dramatically in recent years, so you’ll want to know it’s all accurate.

Every week, Mansion Global poses a tax question to real estate tax attorneys. Here is this week’s question. 

Q: I live in King County, Washington. I want to appeal my property assessment. How do I go about doing so?

A: This year’s notices of the assessed value of homes in King County, Washington, which includes Seattle and Bellevue, are mailed between May 2019 and November 2019, according to the Department of Assessments’ website.

Homeowners then have 60 days to file an appeal of the assessment, said Waverly Cassill, a real estate broker and the lead residential appeal specialist at Harley H. Hoppe & Associates, Inc., a property tax appeal firm based in Bellevue.

The effective tax rate in King County is .91%, according to Irvine, California-based ATTOM Data Solutions, and homeowners pay an average of $6,865 a year in property tax.

Residential property in Washington is taxed at 100% of its market value, Ms. Cassill said. And values have been going up about 1% a month in recent years, she added.

With that in mind, “you can assume that your value will go up by 12%” from one year to the next, she said. However, homeowners who don’t think they could sell their home at that assessed value can appeal.

For starters, if a mistake has been made in assessing the home, like if the square footage or other details have been recorded incorrectly, that should be brought to the attention of the Department of Assessments before starting an official appeal, according to its website.

Otherwise, the Department of Assessments allows homeowners to appeal either online or through the mail, Ms. Cassill said.

“You need to do the leg work and find the evidence in support of a reduction,” she explained. And it needs to be strong evidence, because the burden of proof is on the homeowner.

“Under Washington state law, the assessor is deemed correct,” she said. “That makes it really challenging…the proof has to be very strong.”

That evidence could be proof of the purchase price. If a homeowner made his or her purchase close to the end of the previous year, then the appraised value is not likely to go up very much. In that case, any large increase could be grounds for appeal, Ms. Cassill said.

Or a homeowner could have an independent appraisal or a realtor market analysis done, she noted. If either determined the assessed value to be too high, it would be useful for the appeal.

The step-by-step appeal process includes selecting comps—or recent comparable sales of homes in the same area—and stating the reasons for the appeal. Location, condition and amenities, as well as things like traffic and noise issues, are all part of the equation.

“There’s a lot involved when you’re looking at comparables,” according to Ms. Cassill.

After filing, homeowners will be notified by Board of Equalization that their appeal has been received. The Board of Equalization will ultimately determine if a reduction is warranted.

“But it’s not something that happens overnight,” Ms. Cassill said. “It can take six months, even up to a year….and by that time, you’ve already paid your taxes, so you’ll be getting a refund or a credit to the next year.”