I have a 40 gallon fresh water tank. We took 2 quick showers, a few toilet uses and a small dish washing and my tank was showing empty. What is the average dry camp water use? Seems to us, 40 gallons ...
Also, don't leave the water running while you are washing dishes. Wash in one sink & stack the soapy dishes in the other. Then rinse all the soapy dishes at once.
Agree with others about the low-flow shower head & navy showers. The Oxygenic shower heads are great.