Delinquent first-mortgage balances sank to $500 billion in March, the lowest since January 2009, according to Equifax’s (EFX) March National Consumer Credit Trends report.

The report, a joint product of Equifax and Moody’s Analytics (MCO), showed 49.5 million outstanding first mortgages, marking an 11% decrease from the peak of more than 55 million in March 2008. These balances were 3.5% lower than last March and have now posted year-over-year declines for the last 36 months.

The report indicates the decline was caused by high foreclosures and loan payoffs as well as low homebuyer demand.

"The residual effect from the recession and housing bust continues to be an obstacle for both lenders and borrowers in the housing market," said Equifax Chief Economist Amy Crews Cutts. "We're seeing effects of the economic recovery within existing accounts in the form of fewer delinquencies and foreclosures, but not a substantial amount of new activity as home sales and resulting new-home financing fail to keep pace with payoffs and foreclosures."

For delinquencies within existing home equity credit lines, 79% came from loans originated from 2005 to 2007. The number of revolving home equity loans is at a five-year low, with 11.6 million outstanding as of March 2012.

Home equity installment balances have dropped 46%, down to $150 billion in March 2012 from $275 billion in March 2008. In March 2011, delinquent balances in foreclosure totaled nearly $862 million. In March 2012, that number had decreased nearly 30% to $604 million, the lowest since mid-2007, and marking a 14% decrease from March 2011.