Construction has begun on a 115-room Quality Inn in Georgetown on the site of a former gas station at the southwest corner of 30th and M streets NW.

Developer A.L. Wheeler, a lawyer and long-time Georgetown resident, said he and a son, James, will retain ownership of the hotel that will be built with a two-story, federally styled front section along M. Street. The main part of the hotel, seven stories above ground, will be behind this. A new Marbury Place, a private road, will run from M to 30th between the buildings.

In addition to its name, the hotel will use Quality Inns' reservation and marketing services. But management will be under the control of Wheeler and his son.

The 137-by-140-foot site adjoins a hotel built 11 years ago on Thomas Jefferson Street by Wheeler and leased now to Dutch Inns of America. Two blocks to the east, the Four Seasons Hotel is due to open within a few months as part of a major complex being developed by JBG Associates.

Wheeler said the new Quality Inn will have moderately priced rooms, below the level of luxury hotels. "But we have the latitude to do something different than the usual franchise hotel operation," James Wheeler said. He pointed out that there will be spaces for small shops and three restaurants - including one specializing in appetizers. Four levels below grade also will have meeting rooms, some office space and parking.

Clas, Riggs, Owens and Ramos of Silver Spring designed the hotel. It will have a slate roof with eagle-shaped snow guards, a full brick facade that was approved by the Fine Arts Commission after nearly two years of discussions. A pool and sunning area will be situated at the rear of the hotel.

Edward M. Crough Inc., Rockville, is the general contractor. Construction financing of $5.5 million was arranged by Ivor B. Clark Co. Inc. and chattel financing by Central Fidelity Bank of Richmond. Richard Himmel of Chicago said that the hotel rooms and interiors will be 17th and 18th century reproductions.

A cobblestone preomenade below grade will be a feature of the new Quality Inn that will have one and two-bedroom suites, nine of which will be on two levels.

Jerry Manion, senior vice president of the Silver Spring-based Quality Inns International Inc., said 13 franchise hotels and inns now are operating in the Washington metropolitan area. One is a converted apartment, the Qualtty Inn Downtown just above Scott Circle, where occupancy has been 90 percent. Manion called the Georgetown hotel a "major step in our expansion drive."

It is scheduled to be open in the spring of 1981. CAPTION: Picture, New Quality Inn in Georgetown, in artist's drawing of M street front and larger building in rear. Quality Inns International