Two different systems. Chill Water was the Main A/C loops that fed the fan rooms from the chillers. We had 10 chillers running an open loop around the ship rather than isolating it into two or three loops.
Drinking {Potable} water came from the Chill Drinking Water system. Each unit was probably on most carriers in 3 & 4 pump rooms. We did away with using it in early 78 and installed regular water fountains. They were more efficient. But as of our 1980 overhaul I believe the machinery for the old system was still in place on our ship. Even back then it wasn't wise to drink from the A/C chiller loop as it had too much crud in it. It was supposed to be a closed system.
BTW, ever have any problems with a chaff fodded flight deck?