The protagonist (ordinary joe and husband/father), comes across a leprechaun while on a fishing trip. He somehow insults the leprechaun (maybe not believing in it?) and the leprechaun decides to teach him some manners. He places a magic curse on the man, telling him he won't be able to touch or use water in any way.
IIRC, the man doesn't believe the threat, until he gets home. His daughter is bringing a boyfriend over for dinner, and he tries to take a shower. Sure enough, the water will not touch him. I remember the man not being able to shave, either. He shows up to dinner, scruffy and a bit dirty. There's a line about how he disliked the boyfriend's waxed mustache, but was hardly in any position to say anything about it tonight.
The curse goes on for several days, with the man getting dirtier and scruffier. He also has a habit of being half-popped, as he can't drink water either, and has been drinking beer instead. Eventually, the man goes back to the lake where he met the leprechaun to apologize. He is able to walk out into the middle of the lake (as the water won't touch him). He may have offered the leprechaun a gift of some sort, along with the apology.
The story ends with the leprechaun lifting the curse, and the man splashing into the water. He's soaking wet, but overjoyed to be so. Something like that.
Timeframe of Publication
Not sure. Old, definitely. I think I read it in the early 80s or late 70s, but I remember the book being beat up and the pages yellowed with age even then. The writing style of the story also suggested an older story. I'm afraid I can't be any more specific than that.