Originally Posted by
Redstone
If the lavitories are vaccum type with remote storage tanks, then yes the initial "squirt" of water before the waste is sucked away is potable water. As sys4 noted, it is an antisiphon valve in the system at the crapper that prevents cross contamination. Stick to beer and whisky if you feel you must rehydrate.
Hadn't thought of that, sorry! In that case - Pimms O'clock!