By simply adding a rain water cistern catch system with sides and the bottom using rain gutters, homeowners can funnel the rain into large underground or above-ground tanks/barrels, depending on need. This innovation could work for residential and commercial sites due to an easily adaptable DC pump ran by the PV for irrigation systems.
These rain water systems could even be used for emerging markets even as drinking water. Rain water is easily purified, if necessary, using reverse osmosis or simple solar distillation.
I am working with the premier air to water manufacturer to produce the first commercially viable solar-powered machine to simply pull the water directly from thin air. This concept uses the same technology that your A/C systems use to remove heat from air. The byproduct of this process (removing heat from air) is water--why not put this yield to use in areas where water is difficult to come by?
Photo credit to Izik.