This is an all too common scenario -- you start eyeing with suspicion a house down the street.

Maybe there is a portable storage unit sitting in the driveway, or piles of stuff accumulating at the curb on garbage day. A "for sale" sign appears but the owners won't tell you where they are moving or why. Rumors float down the street. Then one day the neighbors are gone, the "for sale" sign disappears and the house sits vacant for months.

Foreclosures are not only stressful for the owners involved, but for the neighbors around them, who worry about reduced property values and blight on the neighborhood.

Both concerns are valid, to a certain extent.

The impact of a nearby foreclosure on your own home's value is not so cut and dried, says Dave Hanna, president of the Chicago Association of Realtors.

"In some areas, there are so many distressed sales comps they create great downward price pressure," he said. "But in some other areas, the market is only marginally affected. Multiple forces are involved -- the lender's guidelines, the appraiser's approach, the number and quality of available comparable sales that are not bank owned or short sales."

Several area municipalities are increasing their efforts to prevent blight from vacant buildings. The City of Chicago, for instance, last November added more teeth to its vacant properties ordinance.

Vacant buildings now have to be secured at all times, said Bill McCaffrey, spokesman for Chicago's Department of Buildings. Plywood can be used to cover doors and windows for the first six months, and after that, the owner must use a third-party security system or cover openings with steel panels.

Covered doors and windows don't give the neighborhood a "come hither" look, but they do prevent vandalisms, break-ins and criminal activity.

Existing building codes already address basic maintenance, such as keeping lawns mowed, sidewalks shoveled, rodents at bay and trash off the property, but if you see a poorly maintained property, call 311, McCaffrey said.

You could also try calling your alderman.

"I can't speak for every alderman's office," said Ald. Ginger Rugai (19th), "but when we get a complaint about a foreclosed home, we contact the bank or Realtor who is representing the home."

In some neighborhoods, concerns about a suspected foreclosure start well before the property is vacant. Of course, neighborhood rumors are not always reliable. Here are several ways to get more reliable information -- and not have to pay for it:

1. Go to Realtytrac.com and use the clickable foreclosure map. Realtytrac will let you see a list of foreclosures by Zip code and then give you the street -- but not the street address -- on which a foreclosure is located. You can use the same process for bank-owned, pre-foreclosure and auction-ready properties.

2. Search through pre-foreclosures, foreclosures, bank-owned and auction homes for the street on which your suspected property is located. This may look like a daunting task, but I found a likely suspect in just a few minutes.

3. Once you find a possible prospect, you will be given the property's most recent sale price, as well as the date it was recorded.

4. Switch to a real estate transaction Web site, such as our transactions at www.searchchicago.com/homes. Type in the Zip code, then use the sale price and a 30- to 60-day date window to search through the transactions. The transaction data on searchchicago.com/homes goes back to 2003; for earlier sale dates, use another Web site.

5. Match up the sales price and approximate date to the likely prospect you found on Realtytrac. The transaction data will give you the exact street address. If you are still not sure you have a match, often you can confirm it by using Google's street view in its mapping program.

Recently a friend whose home is for sale realized that a house right across the street might be heading for foreclosure. She thought she knew the owners pretty well but they refuse to reveal why they are moving. She asked her Realtor, who found out that the house had in fact, recently become bank-owned.

Now my friend's concerns are: Will the foreclosure affect the sales price? Will it be kept up, or become neglected? Should she tell her other neighbors? Does that fall under the category of gossip or information?

What do you think?