I recycle the water. I stand in the big bucket so the majority of the water goes back into the bucket. With me and the Mrs, sometimes we share the same water depending how much water is available where we camped.
I usually add about 7 or 8 litres of hot and about 15 of cold (if water is plentiful where we a camped). The kids can share the water.
I guess with 5 people, the current draw could add up. Mine draws 2.5 amps. So for me and the mrs having a 10 minute shower each would only draw 0.8Ahours.