The crew at the Bexley Park Pool near Cleveland includes two sets of identical twins: 17-year-olds Anna and Maia Wachter, and 18-year-olds Ariana and Amara Jester.
Pool manager Lauren Meek tells The Plain Dealer newspaper of Cleveland she has no trouble telling the Jesters apart but can get confused by the Wachter girls, both lifeguards.
The pool's two other pairs are fraternal twins.
Meek says it's common for siblings to work at the pool but having four sets of twins is very unusual.
The pool in South Euclid has 34 employees, meaning nearly one out of every four is a twin.