I have an 1895 Miner's Cabin at high elevation. The service line freezes without fail any time the temps drop below 20 degrees. We are on municipal water that is NOT metered. Last winter I had to let the bathroom faucet drip all winter to keep the lines from freezing. This is not good for the septic system. I have an exterior hose bib that I am considering running at a small flow all winter to keep the water from freezing. What is the best valve to use for this application?