The efficiency of pumped hydro storage depends heavily on the height difference involved. There's not that many suitable sites, most have been developed already

The efficiency of pumped hydro storage depends heavily on the height difference involved. There's not that many suitable sites, most have been developed already. It's not a technology that scales down well other than vanity projects. Rooftop cisterns are very common globally, usually places where the water utility if it exists is unreliable. A huge number of humans get their water from a truck that comes by weekly or such to fill the cistern. In more high income nations, this isn't necessary because the utility does the same thing at a larger scale with one or more large water towers interconnected. Someone I know built an off grid air bnb on the beach in Mexico using Earth Ship concepts. I helped out with one of the buildings a little bit, doing the earth bag construction. The passive temperature regulation of those nice thick walls is impressive. He uses well water, and solves the water pressure problem by having a pump that sends it up hill to a pair of cisterns, for hot and cold water respectively. The hot one is the big black plastic ones you see on rooftops everywhere in Mexico. The cold one is made of reused plastic soda bottles and concrete underground. They both are surprisingly effective at what they do. The hot water is frankly way to hot to use without a mixer. It'd be entirely pointless to use it as energy storage though. The pressure just isn't that high, and the total volume of water involved in the system isn't sufficient. He uses a battery array to buffer his solar. As cool as all that is, you couldn't build an entire city that way. It's just not dense enough, and again ends up being mostly a vanity or tourist thing.