I can shower, cook, clean on 1 gallon a day. Drinking /cooking water is not out of the camper tank, so that does not count.
I come back in the evening dirty and nasty sweaty so it is a legit shower.
Use kids shampoo. It will suds up less and is easier to rinse.
Don't wash hair every shower unless you got dirty or sweaty.
There are water saving shower methods where you can shower with very little water.
Do not heat water for a shower, suffer and be glad to get out of the cold water, you will use less water.
Turn off toilet water. Put a bucket of old dish water for the flush and a jug for the guys, or if you can't salvage flush water then use a plastic bag for the black water/affluent so you use no water.
Do not run water for brushing teeth. Use a small cup to rinse mouth, and a drop of water to rinse off toothbrush.
Don't wash your hands. Use wipes or a gel dispenser, it will clean better anyway.
And of course bring extra jugs of water.
My fav tip is to use a Lifesaver Jerrycan water purifier. Take water from any source like a stream and filter it and put this back into your camper water tank. The base model Lifesaver filter can do 10,000 gallons before needing replacement. The life is 3 years, it will be very hard to reach the 10,000 limit in 3 years, even full-timing in the RV.
