The Home Affordable Refinance Program to help underwater homeowners refinance into lower-rate mortgages — and thereby lower their payments and stay in their homes — has finally started to catch on in the Washington area.

HARP’s initial impact was limited, even as interest rates dropped, reaching only about 900,000 borrowers between 2009 and 2011 instead of the several million policymakers had anticipated. Last fall the Federal Housing Finance Agency revamped the program, removing the loan-to-value limit and reducing fees and appraisal parameters. The revisions also eliminated several barriers to lender participation.