Anyone use hydro power to be "off the grid" ?

HomePower magazine has some great info on this. Also, Real Goods has books and materials available...you can check on-line for their web sites. You need to determine flow rate, and head...just like the other answerer said. There has to be a difference in elevation between the water source and the pelton wheel (micro-turbine) as well as sufficient flow in order to create electricity. The bucket method for determining flow rate is good...use a container of a known size, and time how long it takes to fill it to find GPM (flow rate). Then you need to find the elevation difference. You will get .43 PSI for every foot of elevation (or about 1 PSI for every 2 1/2 feet elevation). Once you know flow and head (pressure based upon elevation difference), you will be able to determine whether this project is feasible or not. If you have more questions, I will try to answer them. Good luck!