Depending on the size, I believe they make a 1 inch and a 1/2 inch version, I know that they due have a maximum flow rate. They have a plastic, rotating, spinning, gear that switches the water direction. Too much flow will cause it to not work. They are notorious for getting sand particles in the gears and thus stopping the rotation. I have rinse and jiggled and wiggled to dislodge different particles out of mine. Sometimes a vinegar soaking. Try to make sure it recieves a "clean" water supply will help with the recomended flow or pump.