If you live in an area that is prone to natural disasters like tornadoes, hurricanes, floods or earthquakes, you probably have some sort of emergency supply kit with food, water and other emergency supplies you might need. (If you don’t, you should!)
What if the campground or RV park you are at has their own mini disaster and the water supply is disrupted for some period of time? Maybe a construction project or accident cuts off the water supply for a day, or mayby there is some contamination problem and people are required to boil the water before using it. What will you use to wash your dishes or flush the toilet?
Uh, what about the fresh water holding tank? Got any water in there just in case something happens at the campground? If not, maybe you should. You don’t necessarily have to fill up the fresh water holding tank all the way, but at least put some water in there.
I used an empty milk jug to figure out how much water each kitchen sink would hold (about 4 gallons), how much the bathroom sink would hold (about ½ gallon) and how much the toilet bowl would hold (about 1 gallon). So now I can estimate how much water a meal of dishes uses or a flush of the toilet uses.
If there was a water shortage or outage of some sort, we could always use paper plates, but there could still be pots and pans to clean. We might end up using 3-4 gallons to wash and rinse. Hand washing, toilet usage and a few other things during a day might use another 3-5 gallons. I’d probably head for the nearest store for some bottled water for drinking and cooking so we could use the holding tank for the other things. All totaled, we could end up using 5-10 gallons of water per day for our family of 4. So I’d probably put about 20 gallons of water in my tank, just for that unexpected emergency.
Do your own calculations and see what you come up with. If you’re tight on weight limits (water weighs 8.25 pounds per gallon) and can’t carry the water with you as you travel, fill up the tank when you get there to the desired level and use it the last day you’re there.