During necessary power cabling rearrangement in the U.S. toilet area of ISS, the astronauts needed to disconnect some plumbing, and in doing so sprung a leak.
“While demating the QD (Quick Disconnect) that supplies potable water to WHC [toilet] at the rack the crew reported a sticky QD that caused potable water to leak into the cabin,” noted L2 ISS Status Information.
“Initial troubleshooting of the QD leak did not resolve the issue and the crew ultimately remated the QD, however not before ~11 L[iters] of water was leaked. The crew was able to clean up the water using a significant number of towels, and after isolating the potable bus at the PWD [?] the crew demated the QD at the outlet.” [emphasis mine]
Isn’t it lovely how NASA uses acronyms to make everything clear? Seriously, in plain language what appears to have happened is that, in order to prepare the toilet for the future arrival of a new urine recycling unit, they needed to reroute a power cable, and to do that they needed to disconnect the toilet from its plumbing. When they did that disconnect, however, water poured out. The highlighted and very vague language above is designed to disguise what appears to have been a very dumb error that caused the leak: They forgot to shut off the water before doing this, what I think is the “potable bus at the PWD”.
The report also says “It is not believed that any significant amount of water made its way behind any of the racks during the cleanup.” This might be true, but I bet that astronauts are going to finding tiny blobs of water in all kinds of nooks and crannies for quite a while. I hope these blobs don’t cause other problems, such as mold (a constant concern on space stations), corrosion, or electrical issues.