Home value depreciation remained steady in August after improvement stalled in July, according to the Zillow Real Estate Market Report released Friday.

The Seattle-based company’s market data shows that nationally, home values fell 0.3 percent between July and August (about the same as the change between June and July) and declined 3.8 percent from their year-ago levels.

According to Dr. Stan Humphries, Zillow’s chief economist, the data clearly illustrates that a bottom in national home values has not yet been hit and will come later this year or in the beginning of 2011 at the earliest.

The distressed housing inventory continues to weigh heavy on market values. Zillow reports that the foreclosure rate, defined as the number of homes foreclosed in a month as a percentage of all homes, climbed again in August to 0.113 percent, up from 0.109 percent in July.

Foreclosure re-sales as a percentage of all sales in August also increased to 19 percent, up from July’s level of 17 percent. In short, the pace of final foreclosures picked up as these foreclosures became a larger portion of monthly transactions, Zillow explained.

Out of 124 metropolitan markets tracked by the company in August, 93 saw negative year-over-year change in home values, 14 saw flat annual change, and 17 saw positive gains.

California markets dominated the list of metros with the highest annualized home value appreciation rates, with Salinas, Merced, San Diego, Los Angeles, San Francisco, and San Jose topping the list. Non-California markets on that list included Oklahoma City, Little Rock, and Stamford.

The markets seeing the largest declines in home values on a year-over-year basis included Ocala, Bend, Miami-Fort Lauderdale, Phoenix, Orlando, and Detroit.