basic principle is that there's a long pipe going up a river, the water gets going fast, it pushes a solid brass ball to close the outflow end, the pressure of water in the pipe redirects up the stack. it lifts a hollow brass ball so the water can flow into a pressure vessel. the back pressure causes the water to stop moving, then pulls both balls back into start position, water begins to flow again making cycles. you don't need a pressure vessel, but the water will pulse. i suppose a relief valve might be needed in really high head setups, but where i'd use it there ain't no mountains.
now, of course the water's cleanliness is an issue, so boiling, filtering and storing is a good method to prevent premature water related death.
one thing that is an improvement is a tiny hole behind the lower valves closed position, with sand getting in the lower chamber it can clog it and lock it up, a hole there will allow the sand to leave before it becomes a problem.
this is not my design, it's well over a thousand years old, and some of the originals are still in operation, i'm guessing they weren't made of wood.