Remember back when we moved in here, stayed one night and then were asked to move to a new space? Well when we moved I closed the grey and black waste valves, unhooked, moved and reconnected the hose. However I forgot to open the grey water valve so the waste water from the sinks filled the holding tank and started working it's way back up the drains. The shower base, being the lowest place the water could escape the pipe, began filling up and the water was just about ready to overflow the shower pan and to run onto the floor!
I rushed out, pulled the valve and came back in to face the music. As they say, it could have been worse. The water was mostly rinse and dishwashing water from the kitchen sink and whatever from the bathroom sink and was dirty but not disgusting but needless to say, our wash this week will require a few more quarters.
As usual, all my fault. :(