Washington Gas has filed a request for a 7.7 percent rate increase for its 151,000 District natural gas customers, arguing its current charges no longer meet the price of doing business in the city.

The application, filed Thursday with the D.C. Public Service Commission, would increase Washington Gas’ annual D.C. revenues by roughly $20 million. The typical residential heating customer would see an increase of about $8.47 per month, or $101.64 annually. The request is the first since 2003, and would take effect Oct. 1, if approved.