The pool is called BayWatch. It is located on 19th floor. Go through the lobby and go up top the 10th floor, then change elevator to go up the 19th floor, you will find the pool as you get out of the elevator. Changing rooms are in the corridor on the right when you are facing the pool.
MRT: Somerset (North South line)
BUS: There are two bus stop nearby:
CAR: Parking at OrchardGateway is $3 for 1.5 hour.
Showers, Towels, Changing rooms.