It really depends upon whether you are hooking up and your RV is staying put for several days or if you are using your RV as your vehicle during the day to tour the sites. We are traveling out in the RV every day and coming back at night. We fill the fresh water tanks at home before we leave and run off of them until they need to be refilled - then we refill them from campground water. It is enough to unhook electric every morning. We don't need to deal with putting away hoses too. If we were going to stay in the RV in one place and not move it out of the campsite at all, most likely we would hook up to city water.
We use the city water hookup if we are not leaving early. If we need to pull out early we use the onboard tank so as to minimize any noise we might make in the morning getting ready to go. I also leave the fiver hooked up to the truck for the same reason, just unplug from the truck as I have never tested to see if there is a battery isolator on the truck.
Goody Two Shoes and the Filthy Beast
2008 Silverado 2500HD
2012 Wildcat 282RKX
You cannot make things idiot proof, you can only make them idiot resistant.
Good advice both ways. I keep about 1/2 tank of fresh water (50-60 gal)and use city water if it tastes, smells, and looks OK. I have had my share of foul-tasting city water and, like others, have been caught without city water for one reason or another.
2016 Ford F350 Dually
2011 Mobile Suites 36TKSB3
Reese 25K Hitch
Michelin 17.5 XTA Radials
We don't have cross feed from the city hook-up to the potable tank, but the potable can't be gravity filled - it has a female hose-thread connection also.
We have some of the best nmunicipal water in the country in Anacortes, so we always leave home with the potable tank freshly filled. If we find the CG's water tastes weird, We shut off the city faucet and use tha tank/pump to fill a couple of jugs for cooking and drinking for the day. CG water then goes back on for potty, shower and sink uses.
I'm giving some though to getting a solenoid valve to put on the CG water inlet so I don't have to go outside to the pedestal to switch over.
Frank Damp, DW - Eileen, location Anacortes, WA, now retired RVers (since Dec 14)
Dog - 1 Lab, a yellow male, 13 yrs old July 2016.