Everyone wants lower property taxes. Beware scams in which companies charge fees to dispute your property assessment.

In many cases, you can challenge your property assessment on your own, free of charge, without expending a lot of time and effort.

Experts recommend homeowners watch out for the following.

  • Letters made to look like they come from government agencies, but they really come from private companies.
  • Offers to file a challenge of an assessment — for an upfront fee.
  • Services that request a certified copy of your property deed.
  • Companies that ask for your Social Security number.

Worst case, pay for nothing

The most prevalent property assessment scam works like this: You get a letter in the mail that looks like it comes from a government agency, offering to get your property taxes reduced. The “agency” charges as little as $30 all the way to hundreds of dollars for the service.

Not only do these companies misrepresent who they are, but in flagrant cases, they take money and do nothing.

Some companies actually perform some work by filing a request for a property reassessment on your behalf. But you can file for a reassessment on your own, free of charge, so it’s an unnecessary service, says Steven J.J. Weisman, a Cambridge, Mass., lawyer and an identity theft and scam expert. “The key thing is, these companies aren’t doing anything you can’t do for yourself.”

Timing is everything

Scam artists often mail fliers a few months ahead of when the town or county will do its own reassessments, adds David K. Ginsborg, deputy to the assessor in Santa Clara County, Calif.

In Santa Clara, reassessments are done in June. If the home’s value has fallen below the assessed value from Jan. 1, the county cuts the property taxes automatically. Scammers, targeting homeowners who are likely to have their property taxes reduced, mail fliers in March and April. Homeowners pay the scammer’s fees, and in June their property taxes are reduced. But their property taxes were going to be cut anyway.

“These folks are very deceptive,” says Santa Clara County Assessor Larry Stone. “There’s no reason for anybody to pay for a service that the assessor provides for free. This is a terrible thing to do when people are really hurting for money.”

The best defense is to toss the advertisements in the trash. If you don’t agree with the county’s assessed value, you can fill out a form provided by the tax assessor to appeal.

Tread carefully

What if you don’t have time or desire to appeal your assessment, and you want to hire one of these services to do the work for you? Experts say you should avoid any companies that charge upfront fees or purport to be affiliated with government agencies.

Another thing to watch out for: a company that asks for a certified copy of your deed, and charges more to get the copy than you would pay if you got the copy yourself.