Water works (by the Watergate Plumber Co)
Slowly but surely all the flight-crew lavatory plumbing is being relocated to the flight-deck in order that the crew should not have to enter the cabin. It is a security precaution.
There's an NPRM out already for relief tubes to be fitted to each pilot's seat. Jump-seats are to be converted to toilets.
The above incident was a prelude to the new cockpit shower mod.