Mechanical power storage is entirely possible, but, the scale of it is beyond the scope that most people can safely build. I might do something with that in the future since building strong stuff is totally in my wheelhouse.

I already produce "excess solar," but I've yet to find a very good way to shunt that into something like a water heater or non-typical battery storage. Yet. I will.

About water storage, specifically, an old school wind-powered water pump to lift well water into a holding tank (like you'd see out in the West of the US before and just after the turn of the least century) would be a really good use of wind power to provide a good way to lift water and greatly reduce pumping power required to maintain good pressure in your water system, mostly passively. (You'd need to maintain the windmill occasionally and make sure the system isn't leaking, but... Some of those setups are still functional after nearly a century with minimal maintenance, which is one of the things that I consider when pondering what to do as I build my home.)

Also, as a side note:

Reducing the need for electricity is a very good goal, in general. If you think about systems outside the literal box that most of us modern idiots have gotten ourselves into, you can find many ways to overcome the un-optimized lifestyle that most of us live. I don't want to build a direct replacement for most of the systems of a modern house, since, they are designed to be barely single use. I'm thinking about building for many generations.