I already have a Z-Wave main water line shutoff. I hadn't decided is/when the dishwasher leaks to shut off the main water or just shut off the electrical switch to the DW. Or perhaps both.
I plan on running the sensor cable through the floor which will provide both ease of changing the battery and physical indication of any leaks (dripping from the ceiling in the basement.
I simply just slip one under the dishwasher. Front baseboard cover comes off easily. I also have one under each sink in the house on the floor. 1 mounted to each water heater with a probe in each pan. (I run tandem water heaters). About once a month I test one at random.
Sensors at every sink and behind each toilet, under dishwasher, under fridge w/ ice maker. Water heater and AC drain (same floor location), sump pump well, Water supply cutoff valve after pressure tank and shut off switch for well pump power. I have a rule that test cycles the shut off valve once a month to keep it from sticking. Our cleaning person manages to test the system every couple of months.
Not so much after I add the kitchen baseboard. Besides I'm going to drill a hole in the floor anyway. When I installed the recently leaking DW, I shot myself in the foot. I created an RTV "dam" around the installation so more water had to leak before I saw it (didn't have a leak sensor).
With the addition of this sensor, everything with water has one or two leak sensors.
I even have a sensor in the A/C (attic) evap overflow pan.
Unfortunately I seem to have been adding something after a problem has already occurred. But with this addition I will have a sensor under everything that could leak, with the exception of the water meter.
Unless you turn off the dishwasher supply valve under the kitchen sink, there is always a possibility that the feed line between the valve and the dishwasher inlet fitting will rupture or leak. Turing off the power to the dishwasher will do absolutely nothing to stop the water flow. You need to cut off the main water valve until the dishwasher supply valve is turned off.
To avoid a potential electrocution hazard, turning off the electrical supply would also be a great idea, but by itself, it is not sufficient.
I'm on a well and have a smart shut off valve as well as a smart switch for the well.
I've toyed with turning off the valve at night, but then the system sucks air if, say, a toilet is flushed. A lot of spitting when the water is turned on in the AM.
BUT....it just occurred to me, that if I just turned off the well pump switch, and not the valve, I'd still have some residual pressure in the (not large) tank, maybe good enough for one flush, or so. Hmmmm....
I don't see any reason to turn off the valve at night, especially with leak sensors present. Going away for a few days? Yeah that's a different story.
Your kitchen baseboard should be cut to go on the base panel of the dishwasher and not be part of the actual kitchen baseboard. This is necessary for both maintenance and safety. You don't wanna have to rip off a full baseboard just to get the dishwasher out. Since it's underneath, if it's cut right, no one will notice the seams.
Keep in mind any water requirements for heating and hot water. With the pump off, and the pressure leaks down your heating may have issues.
I beg to differ. If the leak is in the pump and discharge, and the power is not cut, the pump will drain the dishwasher. Closing the water valve does not stop the water in the dishwasher from being pumped out. This probably will never happen, but removing the power from the dishwasher and closing the water valve ensures no additional water will leak. You are assuming the only leak source is on the supply side.
I did assume the leak would be on the supply side.
I assume that the automatic fill valve is only open during the dishwasher filling cycle. I guess if you turn the dishwasher on and then leave the house, you could get a leak and spill a gallon or two of water on the floor. Since modern dishwashers only use 3-4 gallons of water for the entire cycle, it is unlikely to hold more than 2 gallons at any time. That would cause only minor damage.
If the leak is on the supply side and you are not home, you could spill 1-20 gallons per minute or more depending upon the size of the rupture. That could cause major damage to your home, especially if you are away from home. That is why I was far more concerned about a pressure-side leak than a leak in the dishwasher itself or the discharge tube.
My dishwasher is built into the counter, so electrical code requires it to be to be hardwired electrically. A free-standing dishwasher can use a plug, just as free-standing washing machines, dryers, and stoves. Unfortunately, there is no way of turning off the power to the dishwasher automatically. I would have to open the door manually to turn off the appliance and then trip the breaker.
Yeah that's why I have mine set to regardless of what set it off, the valve closes for the house.
Actually can easily be done with a relay.
Our dishwasher is built in. There is a switch on the wall that can turn off the DW. I haven't decided yet but my thought is to replace that switch with a "smart" switch.
I will likely have the water sensor turn off the main water supply. That way if my wife is in the shower I'll be notified instantly 
Code in my area requires a switch above the dishwasher to cut power to it. This switch could be smartened.
Take a look at this Tuya Zigbee switch.
https://a.aliexpress.com/_mLzKxXy
I have replaced several light switches with these. I bought the no neutral style because there is only a black wire and white wire in the box.
I added a motion sensor to the rooms with the Tuya switch.
Probably a good device, however I will not purchase from Aliexpress. Just my personal decision.
How about eBay?
This is expensive, especially for the "base of the water heater" use case they advertise...but stretch this thing through cabinets and along the base of a kitchen "wall of water" (w/ frig, dishwasher, sink, filter unit, etc) and you've basically covered a lot of risk in one sensor swath.
I've grown to trust what these people make.
Download the Hubitat app
