Our simple solution when remote and water is very precious is to recycle the water and get two showers with only 10litres of water.
Modified the van shower adding an additional 12V pressure pump fitted NRV's prevent shower water polluting van supply.
Heat up a bucket of water over the camp fire tip it into the shower recess start pump and you can shower until the water runs cold.
Dump when finished and you're ready for following day.