OK, can anyone explain my male cat's behavior?

He has a "thing" about hot soapy water. LOVES it.

I like to take bubble baths to relax. He will sit on the edge of the tub and my relaxing bath turns into a struggle to prevent him from drinking TOO much hot bubbly water (I say too much because it's nearly impossible to prevent him from drinking any).

When I do dishes, if I leave something in hot water to soak, I'll find him up on the counter (where he KNOWS he's not supposed to be) just so he can drink the hot bubbly water.

So far, we've been lucky. No ill effects. But that can't be good for him, can it?

Could there be something missing in his diet that the hot bubbly water is replacing? Could it be a hairball thing (he seems to have the most problem with hairballs out of all three cats). He's the only one who drinks the hot bubbly water.

Any ideas would be appreciated.

BTW, he's always done this, but would stop if I scolded him (and he NEVER went on the kitchen counter). But lately, he's completely obsessed.