Real estate experts say that while such misrepresentations aren't new, the tough market of the past few years has made buyers more wary, partly because they can't expect rising home prices to bail them out of costly mistakes. As a result, deals are taking longer, and more of them are falling apart as buyers find properties sometimes aren't all they're supposed to be.

More than 30 states have disclosure laws requiring sellers to tell prospective buyers and agents about leaky roofs and other problems, according to the National Association of Realtors. But there's often a gray area involving the disclosure of problems the seller may not know about, such as a long-ago flood or hidden mold.

States are also increasingly passing laws requiring homeowners to disclose environmental issues, such as the presence of radon gas, a contaminant linked to lung cancer, and underground fuel tanks. In California, the checklist of required disclosures is so long that a cottage industry has sprung up of firms that help sellers prepare the forms.

Given the complexity of disclosure laws, it's not surprising that potential buyers don't hear about every problem in a house. Besides the issue of fibbing, sellers may genuinely not know about problems. And even if they do, the laws generally don't apply to bank-owned homes transferred in foreclosures, which now constitute a larger share of sales.

Buyers need to do their own due diligence and not rely exclusively on what sellers and agents say. They should hire an independent home inspector or home-inspection engineer, one not referred by the seller—and be aware that real-estate agents typically represent the seller.

Common Real Estate Misrepresentations "What Home Sellers Don't Tell Buyers"

"This house is on two acres." Disputes about property dimensions. how many square feet in a house or condo, or its exact boundaries are common. Sometimes buyers don't learn the exact dimensions until the lender's appraisal. Smaller dimensions also can cause an appraisal to come in lower than the agreed-upon purchase price. Low appraisals are a leading cause of ruined deals in today's market. A properly worded appraisal contingency in the purchase contract would allow you to scuttle the deal or find other financing if the appraisal comes in low.

"We Don't Have Pests" A basic home inspection generally doesn't include a peek inside walls or underground for termites and mold, which are among the top complaints. Inspections for mold and radon gas also generally aren't included; usually buyers must order these inspections separately. Other inside-the-wall problems include faulty wiring and old plumbing, which also may require specialists.

"Taxes and Maintenance Costs are Low." Home buyers often gripe about tax and utilities bills that are higher than sellers said they were. Homeowner association and condo dues and assessments are also common complaints. Sometimes sellers simply underestimate the bills, or forget to include recent or expected increases. Taxes can also be deceptively low because of unrecorded improvements like decks and finished basements. Ask to see recent bills, and check with the tax assessor's office for up-to-date information.

"This is a Quiet Neighborhood." Sellers may play down distractions that could drive you crazy, such as barking dogs or idling buses. A charming park by day could be a teen hangout at night. Your best bet is to view a property at different times of the day.

"There's Going to be a Golf Course, a Pool and a Party Room." Builders of many developments that broke ground during the housing boom ran out of money before the project was completed. Many homeowner and condo associations also are strapped because of delinquencies and defaults. Some states require upfront disclosures about this, but you should also ask neighbors, not just sellers, about any promised facilities. Also, check titles to be sure that specific parking spaces, storage units or other facilities are included in a property sale.