WASHINGTON — Rates on 30-year mortgages fell slightly this week to the lowest level since mid-July.

Freddie Mac, the mortgage company, reported yesterday that 30-year, fixed-rate mortgages dipped to 6.47 percent this week, down from 6.52 percent, which had been the rate for the previous three weeks. The new rate was the lowest since the week of July 17 when 30-year mortgages stood at 6.26 percent.

The 30-year mortgage has been above 6 percent since late May as financial markets have become convinced that rising inflation pressures will keep the Federal Reserve from cutting interest rates further even though the economy remains mired in a period of significant weakness.

The Freddie Mac survey showed other mortgage rates were mixed this week.

Rates on 15-year, fixed-rate mortgages, a popular choice for refinancing, fell to 6 percent, down from 6.07 percent last week.

Rates on five-year, adjustable-rate mortgages averaged 5.99 percent this week, down slightly from 6.02 percent last week.