Bryan Smith, Clemson Extension Service
Cold weather is coming. Several sources recommend allowing a faucet in the house to run continuously to help prevent freezing, with a pencil-lead-thick stream of water flowing from the faucet. We measured the flow rate of this pencil-lead-thick stream of water flow in our office. The stream filled a 12 ounce cup in 1.8 minutes. Knowing that there are 128 ounces in a gallon allows us to calculate the flow rate - approximately 3 gallons per hour. Now let's talk about folks with wells and folks with city or county water.
Wells - if you have a standard well with a 40 gallon bladder tank, the actual "drawdown" amount (the amount that leaves the tank from the time the pump turns off until it turns on again) for the tank is about 13 gallons of water. So if you leave one faucet running with a pencil-lead-thick water stream, your pump will probably turn on once every 4.3 hours (with no other water use).
City or County Water - 3 gallons per hour from one faucet translates into 72 gallons of water per day. For comparison, a normal SC household uses about 120 to 150 gallons of water per day per person, so a 4 person household would use about 480 to 600 gallons per day without the dripping water.
So yes, regardless of your water source it will be fine to leave one or two faucets running during this cold snap. The moving water will help prevent freezing, and the amount of water or electricity used will certainly not break the bank. (Quite frankly I might leave two faucets flowing on the coldest nights.)
