Never ceases to amaze me how many people are afraid of using their onboard water supply. I've owned 3 RVs over the past 30 years, all 3 purchased used. I "think" I may have sanitized (using bleach) my last RV once in the 15 years I owned it, but I could be mistaken.
Always fill up at home (city water system), use that water when camping, refill if necessary at the campground, and let whatever's left in the tank sit when I return home until topping off again sometime before the next trip, anywhere from 2-6 weeks. Yes, I use it for washing, cooking, and even drinking. I've never had any odor or taste problems, other than a bit of "plasticky" taste if it's been sitting longer than 4 weeks, and it pretty much dissipates when I refill again.
Now, admittedly, I'm on city water at home, not well water, and I do understand that some people live in an area that has smelly or bad tasting water...but I don't worry about the source of campground water when I refill while camping as long as it smells/tastes OK. 56 years old and still kickin', so...
