VH Cheer Up:
ZXA, XC & XE (767s) have regular not so little overflows from the forward waste water - one late last year flooding the J class so badly that the J class biz pax through to row 3 having their keep their legs up to avoid the wave of brown stinking sludge (waste water ex sinks not toilet pan although I rekon the toilet may have smelt better).
Tight turnarouds on a busy day 4 leg day so Q just wet vacuumed the cabin, taped the fwd galley and fwd toilet sinks off (pax don't wash their hands anyway I'm told) and sent the plane back out much to the dismay of the entire crew - the left seat was pressured big time by the company with a number of 'managers' turning up at the gate to make the point that it's not that bad.
Thankfully on return to XXX after another set brown waves on rotate & landing, a very thorough person decided to check under the cabin floor including the avionics bay and found traces of moisture. Left seat told attending manager to (words generally meaning) tow it & cancell the flight.
Excellent diagnostic work - shows its not just a case of fixing the reported problem but also using talent, brains and experience to consider the secondary effects/risks.