DOWN ONE -- New Playwrights' Theater of Washington at the American Theater, L'Enfant Plaza. Wednesdays through Sundays at 8 until April 15 with a 2 o'clock matinee on March 31.Reservations, 232-1122.

New Playwrights' Theater of Washington is in temporary quarters at the American Theater in L'Enfant Plaza, but the minor inconveniences of performing in an unknown house haven't hurt its latest production, "Down One" by Barbara Keiler.

Called by its producers a comedy of suburban lifestyles, the play is a proclamation of the individual rights, personal needs and motivations that have sprung from the raised consciousness of Today's Woman.

Under the firm direction of Alan Donovan, the portrayal of four bridge-playing Long Island housewives is perhaps a bit too broad, but what is lost to unsubtle characterization is gained in the clarity of the story line. Points of view are well-defined, letting the story unfold neatly and concisely. (The two acts run about 90 minutes including intermission.)

The plot in brief: Three white, not-quite middle-aged Great Neck housewives are confronted by the fourth member of their bridge group who announces a plan to leave friends and family. She intends to strike out on her own, earning a living as a "member of the household management staff" at a Connecticut estate. Only a quick-tongued black woman who works as a maid for one of the other bridge players is supportive of the idea ("She's going pro!"). The other three try to dissuade her, arguing with a certain desperation that comes from defending their own similar situations.

Phyllis L. Baker, Donna Birndorf, Anne Stone, Sharon Elizabeth Doyle and Bari Biern all handle their roles with care and finesse; they give depth and humor to the characters and a wholeness to the production. The play's single set is handsome and functional and cleverly lit.