my rule of thumb when it comes to standing water is not to drive into anything that goes above the depth of the car tyre, sometimes hard to judge this of course, unless someone else is already in the drink...
the other day in Coventry I was forced to break my 'rule' as I was in a long line of traffic, and only on rounding a corner did I see why, as the vehicles in front of me were heading slowly (thankfully) through a flood, it wasn't too deep (c.5"?) and it would have been very tricky to have turned my car back if I had changed my mind as I was sandwiched in the advancing, slow-moving line of cars!
I was more annoyed at the speed some spooners were doing coming the other way towards us, through the water, causing a wave/surge.
I have just had the Passat brake tested for the MOT and all is well fortunately, though fingers crossed it passes next week (here in NI we have govt run MOT test centres).