Rooftop is the perfect place to collect free solar energy and use it to heat water, these are truly a net 0 system that uses no electricity to heat household water.
Rainwater collection device made from stacking barrels.
Wicking Beds can be very useful in a very dry climate. They regulate the water in the soil as well as conserve water by minimizing evaporation.
Solpal Plus Solar Water Heater is a low tech solution that is a true net 0 water heater. It uses no electricity only photonic energy to heat your household water.