The water pump is 12V DC it works if you are plugged in as well as not plugged in as they are seperate circuits. Leaving it on will get you water when you open a faucet. It will also get you water should you have a leak. That may not be what you want because the water will no doubt be leaking where you do not want it to. Turning it off between needs may save you trouble. If you do have a leak the pump will respond to the pressure change in the system and you can hear it turn on. Off course you would need to be within hearing distance.
The switch is located in different spots depending on the model of RV you have as well as the year. Usually, it is close to the kitchen sink or an adjoining wall. Good luck
I've got a 50-50 chance to suceed, either I will or I won't, those are good odds aren't they?