The sewage and water treatment plants were built in Negril around 1998/1999 as I recall. Where the poop went before that...dunno. I know that the cliff properties relied on septic tanks/cess pools, or so I've been told. Can't speak about the beach. I'd heard rumours of "stuff" being pumped out a mile off shore.

Believe me though, if you were swimming in poop water you'd know. Cholera anyone?