Waterbug or water bug can refer to any of several things:
True bugs

The true water bugs (Nepomorpha), including such insects as giant water bugs, creeping water bugs and backswimmers
Various other aquatic true bugs, known collectively as water bugs
HeteropteraCockroaches

The American cockroach, Periplaneta americana
The German cockroach, Blattella germanica
The Oriental cockroach, Blatta orientalisGiant Water Bug

Belostomatidae

See also
Waterbug Records, a record label