The number of houses put up for sale went up in several US markets in June, a month that typically sees a slowdown in property listings.

The number of homes for sale in 27 large metropolitan areas went up 3.7% from May, and up 2.1% from June 2009. The markets with the largest month-over-month inventory growth were in California and Nevada: up 10.5% in Las Vegas, 9.4% in San Diego and 7% in Orange County.

Only one market in the 27 studied saw a dip in inventory from last month. Jacksonville, Florida, saw a 1.5% decline in the number of houses for sale.

The inventory could increase over the second half of 2010, as more than 7       million homes are either behind in their mortgage payments or are in the process of foreclosure.

The house inventory grew even as demand decreased after the home-buyer tax credit expired. Sales of new homes fell to a record low in May.