[Paul Junkin] bought a curious product off the Internet. It was supposed to generate electricity when hooked up to a running hose. Only, it didn’t do a very good job. His solution was straigh…
To utilize power that is otherwise wasted? The water can still be used in the garden etc. Also if there is a power cut the water often keeps running, so you could use this to charge a small battery or a phone.
If the power goes out you'd probably be better off using solar or a even gas. Maybe if you're using water for something else anyways it makes sense but how much power can really be generated by turning a house on for a min? How much water is wasted?
That requires a much bigger river, that carries enough water to drive a big ass wheel, which limits your options for location a lot. If you take a look at the video i linked in the neighboring comment you can see what is possible with just a little water stream if you have the right setup.