La da dee, la da da,'' echoes the insistent chorus of ''Gypsy Woman (She's Homeless),'' written and sung by Crystal Waters, the 27-year-old great-niece of the late jazz chanteuse Ethel Waters. As the first single from Surprise, Waters' aptly titled debut recording, it zipped up the charts while she was still punching a computer keyboard for Washington, D.C.'s, Board of Parole. Now this dance-club hit with a social conscience has become the summer's mantra, and Waters is so deluged with dates for live appearances she doesn't even have time for nightclubbing.
''The song is about a homeless woman it's not a normal thing to talk about,'' says Waters, who joins Ziggy Marley in August for a three-month national tour. The source of her inspiration? A meticulously groomed bag lady who sings in front of D.C.'s posh Mayflower Hotel. ''In all my songs I like to write some type of story,'' says Waters, whose second single, ''Makin' Happy,'' is set for release this week. ''I always try to write with a little twist or from an odd direction, like poetry.''