I'm installing a drip system for a tiny back yard which includes a two story deck. The water supply is on the ground level and that is where I want to install the controls - valves and timer. One valve will control the ground zone and another will control the deck's container plants. The zone for the ground will get watered longer and less often than the containers. The water supply is at ground level of course. And that is where I want to put the valves and timer. But I'm going to have 80' of 1/2" poly servicing the upper deck - and it will be 12' above the valve/backflow preventer. Every time the water shuts off I'm going to get a lot of water coming out the backflow preventer. Short of putting that valve up on the second level, how can I design this so the backflow preventer is above the upper line?