We have a "FloodStop" gizmo; its sensor lays on the floor. If the sensor gets the slightest bit wet it shuts the water off @ the FloodStop. I know it works well because a couple of times a carelessly aimed bug spray nozzle got the sensor wet and I've had to re-set it (easy done). I can't remember how much we paid for it ... not inexpensive, I think, but well worth the money. On the other hand, with no sensor for the dishwasher, I keep a close ear & eye open when it's running. I already had one dishwasher water problem where I not only had to replace the dishwasher, but also a few floor tiles. Good thing I had a few spare tiles.