WASHINGTON — Rates on 30-year mortgages dropped this week to the lowest level in a month as financial markets viewed new evidence of a slowing economy as a sign that inflation will decline.

Mortgage-giant Freddie Mac reported yesterday that 30-year, fixed-rate mortgages dropped to 6.31 percent this week. That was down from 6.40 percent last week and represented the lowest level since 30-year rates were at 6.30 percent four weeks ago.

All categories of mortgages showed declines for the week, reflecting a batch of reports showing the economy slowing, a development that the Federal Reserve hopes will push inflation rates down to more acceptable levels.

The government reported last Friday that the overall economy, as measured by the gross domestic product, slowed to a sluggish growth rate of 1.6 percent in the July-September quarter, the weakest pace in more than three years.

"Lower than expected third quarter GDP figures helped to put a damper on rising rates this week," said Frank Nothaft, Freddie Mac's chief economist.

The Freddie Mac mortgage survey showed that rates on 15-year, fixed-rate mortgages, popular for refinancing, averaged 6.02 percent this week, down from 6.10 percent last week.

Rates on one-year adjustable rate mortgages fell to 5.53 percent, compared to 5.60 percent last week.

Rates on five-year adjustable rate mortgages dropped to 6.05 percent, down from 6.14 percent last week.