if you decide to go solar...a plastic 2gal garden sprayer (some attach a regular short spray handle) painted black will give you warm water in about an hour (Fla July Sun) and pressure to wash off... be sure to test temperature for kids....I use a dedicated (no insecticide/herbicide) one... a 175' of 3/4" garden hose holds about 2 1/2gal and will get 130F in July Fla Sun after 1 hour... also a 2mil contractor's bag, laid on a flat surface with a 2x4 under the open top, with 2 1/2gal of water, bag collapsed so upper side is in contact with water to remove air, second 2x4 laid on first to seal off bag from wind will also get 130F in the same Sun... you need to have a dipper to remove hot water to mix for shower as even 2 1/2 gal is dangerous to handle in the bag