WASHINGTON — Rates on 30-year mortgages fell below 6 percent this week, recording the first decline in three weeks.

Freddie Mac, the mortgage company, reported yesterday that 30-year, fixed-rate mortgages averaged 5.94 percent this week, down from 6.10 percent last week. It marked the first decline since rates fell on Sept. 18 to 5.78 percent, a seven-month low.

According to the Freddie Mac survey, rates on all types of mortgages were lower this week.

Rates on 15-year fixed-rate mortgages, which are popular with people who are refinancing, dropped to 5.63 percent, compared to 5.78 percent last week.

Rates on five-year adjustable-rate mortgages fell to 5.90 percent from 6.00 percent last week. Rates on one-year adjustable-rate mortgages edged down slightly to 5.15 percent, compared to 5.16 percent last week.