Can't Wait!

It only needs to be on if you want water pressure and you are not on city water. If you are not using your camper or are away from it, I turn it off (don't want a leak while I'm away).

I always turn the pump off after each use. If we are hooked up at a campground and we leave for awhile, we shut the water off. If you are using your 12 volt water pump and you ever notice that it just barely cycles on now and then and you have not turned anything on, you may have a leak. DO NOT ignore this as its an early indicator of trouble. If your water switch has been off for hours or even days and you flip it on, it should not cycle on as there should be pressure in the system. If it comes on as soon as you turn the switch on I would check for leaks.
There is some variation to this as the pump itself could not be holding pressure or a one way valve could leak or toilet valve could seep water into the toilet bowl. This applies to 20 year old RV's and new RV's.

As a precaution against leakage and flooding it is a good idea to turn it off when away from the RV. However when you are around it is fine to leave on all the time.

thanks guys!

I apparently have too many other things to worry about, so I just leave the water pump on the entire time we are camping and using the fresh water holding tank. The outside shower gets used frequently as does the toilet so I just don't bother turning it off until we leave the campground.

Accidents can and do happen so if you have presence of mind enough, go ahead and turn it on and off as needed. Either way, enjoy yourself while you're out there.