Local median home values have declined by as much as 2.5 percent since 2009, while median home values in St. Louis County have dropped more than twice that much, according to preliminary 2011 reassessment data.

The median value of residential properties in the Mehlville School District is $162,500, down 2.5 percent from 2009, the previous reassessment year.

The median home value in Lindbergh Schools is $176,200, a 1.8-percent decrease from 2009.

Countywide, the median value of homes is $140,500, down 5.3 percent since 2009.

The county Department of Revenue last week posted preliminary 2011 assessments of about 389,000 county properties on its website at revenue.stlouisco.com/ias.

Property owners can search for their properties on that site and see their newly assessed value.

The values serve as the base values from which taxing authorities calculate their projected tax rates for 2011.

In April, taxing authorities must provide their projected tax rates to the collector of revenue, who uses them to create the “projected tax liability notice.”

State law requires this notice to be mailed along with the “change of assessment notice” only to property owners whose property value has increased.

These notices are mailed to residential property owners in May and to commercial property owners in June.

Preliminary values may change.

State law requires the county assessor to certify the 2011 assessment roll on July 1. After this date the assessor cannot change values without approval of the Board of Equalization.

County assessment staff currently is inspecting properties and verifying property real estate records and may make changes to property values if warranted.

Property owners who would like to obtain a thorough interior and exterior inspection of their property may request it by calling the county assessor’s office at (314) 615-4230.