A long time ago I posted how I equipped my RV with a automatic shut off valve. Half of the people on here responded like I was an idiot.
What I did was add a 12 volt water valve right where the hose attaches to the RV. Then I installed 4 wireless, battery powered buttons in the RV, one above the shower, one at each sink and one in the wet bay. My water is always off unless a button is pressed. If any button is pressed, the water valve is opened for 15 minutes then shuts off again automatically. That's it. I never worry about a pipe busting and flooding the RV while we sleep or are away.
If you are using the water and it goes off, just press the button again. If you are taking a long shower and you don't want it to go off, press it again anytime during the shower, the timer resets with every press for a 15 minute countdown.
Some people say just use the water in the tank but my tank holds 70 gallons of fresh water and my grey holds 40. Do the math. I guess I could just fill the tank half way but that's a pain. My buttons work great.
I don't think anybody sells what I made so you'd have to know someone who can program an Arduino or ESP8266. I used a NODEmcu, a 12 volt valve, Mosfet and four 433 mhz wall mount switches. Cost me about 50 bucks for everything. There was 12 volts in the wet bay for the light so I just tapped into that. You could program it for any about of time you wished to but I felt 15 minutes was about right. I only have 6 gallons of hot water. Shower longer than 15 minutes and the hot water is gone anyway.
If for any reason something in my wiring failed, simply disconnect the hose and hook it up to the RV directly.
