I am currently taking the required irrigation class to get my Texas Irrigators license. My instructor mentioned that a portable flow meter used to be made to use to measure water flow after installing the backflow but prior to running all pipes. He says the flow meter is no longer made and he does not where to get another. Does anyone know if a flow meter is still made to measure GPM prior to starting install? He says that the bucket method from a spigot is not effective.