Humm... depends on the kind of camper YOU are.
Does your current rig have a fresh water tank? Do you use it? What do you use it for? (some folks won't drink the water out of their water tank)
Do you use paper plates+plastic ware for eating? Eat out of sealed containers?
Do you use pots+pans for cooking? How do you clean your pots, pans, dishes and flatware?
We use our on board water supply for three main things: cleaning, toilet and drinking (we use a filtered water pitcher in the fridge, which we'll refill from the sink). Many modern TC's carry +25 gallons of water (or much more) I suppose its intended to be used for SOMETHING?
While we've sometimes not used the hot water heater and just heated water in a tea kettle on the stove, nothing beats a good pressurized hot water spray from your kitchen faucet to help wash and rinse up after a meal!
We rarely camp long enough to "get ripe" and when we'll use the campgrounds facilities before using the built in shower in the TC. On those even rarer times where we no other choice - we'll use the shower in the TC.
While I think it ranks as the #2 propane use out of the other TC appliances, we like to have hot water on tap.
- Mark0.