DENVER (CBS4) – Homeowners across Colorado can expect to find new property valuations in the mail Monday. And chances are their houses are worth less.

The valuations are done every two years and are based on average sale prices on June 30 of last year.

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Residential property values dropped in at least six area counties.

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Arapahoe County reports an overall drop of 4.8 percent. Boulder County is down 2.7 percent. Broomfield County saw the smallest drop of just .03 of a percent for residential property. It’s also the smallest county.

Denver’s property values fell 4.8 percent. Douglas County had the steepest drop of nearly 9 percent; and Jefferson County reports the average value of single family homes dropped 2.1 percent.

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Homeowners who want to protest the value have until midnight June 1.