Home values saw minimal monthly gains, and the foreclosure rate stayed steady in August, according to Zillow (Z). Housing prices increased 0.1% from July to August, with mostly marginal gains in 68 of the 157 markets covered by Zillow. The national average price of a home was $172,600, down 4.5% from August 2010, and down 28.3% since its peak in June 2006. Pittsburgh, Pa., was the only metro area of the largest 25 covered by Zillow to see year-over-year gains on home values, up 2.8%. (Click on chart to expand the view.) Zillow pegged the national foreclosure rate at 9.2 out of every 10,000 homes for August, down from 10.9 in October 2010. That decrease is due to the controversy surrounding robo-signing, according to Stan Humphries, Zillow’s chief economist. Humphries said that the foreclosure rate eventually “will pick up again,” driving down home values. Prices will not bottom out until 2012 at the earliest, he said. Hard-hit metro areas in California, Nevada and Arizona saw continuing high foreclosure rates, including 32.3 out of every 10,000 homes in Phoenix and 25.2 in Riverside, Calif. Write to Andrew Scoggin.