I use on-board water tank, and refill as necessary. I don't like to leave the RV with water pressure. While unlikely, it is entirely possible that your RV will spring a leak while you are away and flood the unit. It has happened. Search for threads and you will find several. Therefore, turning the water off every time you leave, I feel, is necessary. If you are only using the on-board tank, all you have to do is flip an ON/OFF switch. When you get back, if you forget to turn it back on, flip the switch again. If you are hooked to shore water, you have to go outside and turn the water off. If you forget to turn it back on when you return, you try to use water, then have to go outside and turn it back on. That can be embarrassing if you have just stepped into the shower before turning on the water.