In several hot housing markets across the country, homeowners are heading off constant inquiries from eager buyers and developers by posting “Not for Sale” signs in their yards.

Residents of the suburban Portland, Ore., neighborhood of Lake Grove started putting the signs up on their lawns after being bombarded by annoying inquiries from buyers, and after seeing nearly 20 1930s-era houses torn down and replaced by significantly bigger new homes over the past four years.

A similar “Not for Sale” campaign also is underway in Brooklyn’s Park Slope community, a popular residential area that has seen soaring home-price appreciation recently. Developers have been seeking to build there, where zoning regulations don’t limit the height of new buildings to the same degree as they are limited in nearby areas.

Home prices increased nearly 11 percent nationwide in 2004, the highest jump since 1979. In a recent study, the Federal Deposit Insurance Corp. found that a record 55 metro areas in the U.S. qualified as boom markets, where home prices had appreciated at least 30 percent in three years.