solar water heater DIY, same article has ideas for a compost bin water heater. both very doable. Wonder how well they (esp solar) would work. And I suppose super early morning and late night showers might be a no-go
Outdoor Solar Shower: 2 black painted 5gal buckets w/lids, connected together w/plumbing pie/fittings, attached to a shower head w/cutoff. For easier fillups, cut hole in one lid to insert section of garden hose in it, with hose connecter on ground for garden hose hookup.
Let's see: 100' of 1/2" black tubing ($25), easily dismantled pvc pipe frame with wooden or metal hub (high estimate of $25), two large buckets (one source, one shower supply), and a submersible pond pump ($25-45)-- solar shower anyone?