Main thing is to prove that it is just condensation - then fixing it is easy because you can just make sure people open windows! Always worth going to AskASurveyor.co.uk first to make sure you're not missign a bigger problem, though.
I fitted a Floodcheck automatic stopcock. it knows if the water is running too much or for too long. It's indoors but can't see why it would not work for you guys.