Water and Gas Usage Rates

I often camp in the desert southwest where filling an RV tank can be an issue. The minimum I use is about 2 gallons/day for cooking, drinking and washing dishes. It is hard to get under that and that means heating water to wash dishes and then using just a trickle out of the faucet for rinsing. A shower is about 1 gallon/day. Clearly that is a Navy type shower: wet down, soap up and then rinse again with a low flow and little wasted water. Flushing is not an issue for me. I have a cassette toilet with its own 6 gallon water supply. That amount lasts for at least a couple of weeks.