So this takes place in 1994?
We know Joe was born about 1971, since he tells Zander he was 11 in '82 when he ran away from the boys' home. He must've been 23 when he was a janitor at the school, since there's lots of references to his parents leaving him at the Grand Canyon "fifteen years ago".
The "present" at the beginning of the movie when he's living in the radio station boiler room and still searching for his parents (and Brandy) couldn't have been much longer after that. Even his hairstyle on his new wig when he wakes up after hitting his head on the bridge is a very mid 90s style.
Its weird how they didn't just set it in the present in 2001 when the movie was made, and make Joe 30 instead?