The number of properties receiving a foreclosure filing hit the highest monthly level ever since RealtyTrac began releasing such data in January 2005.

According to the report, default notices, auction sale notices, and bank repossessions were served on 243,353 properties in April 2008, a 4 percent uptick from the previous month and a 60 percent leap year-over-year.

Such trends create serious obstacles for home builders, which are trying to unload their own unsold inventory while homeowners walk away from their mortgages and their existing homes.

Even more difficult, the foreclosure trouble spots continue to be states formerly known as hot spots for housing: Nevada, Arizona, California, and Florida.

In Nevada, one in 146 households received a foreclosure filing, making it the state with the highest foreclosure rate. California was among the top three states in terms of both foreclosure rates and numbers, with 64,683 receiving foreclosure filings.

Additionally, six cities in California (including former new-home Mecca, Riverside-San Bernardino) proved to have among the 10 worst foreclosure rates in the country, as compared to 230 metropolitan areas on RealtyTrac’s list.

Alison Rice is senior editor, online, for BUILDER magazine.