Should I Drip Hot Water During a Freeze?

When It Makes Sense

• Good fit: the hot-water branch itself is exposed. In many homes, both hot and cold lines run inside exterior walls, crawl spaces, attics, or along unheated basements. If the pipe most likely to freeze is the hot-water line feeding a bathroom, kitchen, or laundry fixture, letting that faucet drip can keep water moving and reduce the chance of ice forming inside that specific branch. This is especially relevant for older homes, cabins, mobile homes, and houses with long pipe runs through unconditioned spaces where the hot-water line does not receive frequent use during a cold snap.
• Good fit: you need a temporary fix during a sudden extreme freeze. When the temperature is forecast to drop well below freezing and you do not have time to install insulation or heat tape before nightfall, a slow drip from the hot faucet can act as an interim safeguard for that branch. It works best when paired with other quick measures such as opening cabinet doors, sealing nearby drafts, and maintaining a steady indoor temperature.

When You Should Avoid It

• Warning sign: the pipe is already frozen or the cold is severe and prolonged. Dripping water helps prevent freezing, but it will not reliably thaw a pipe that is already solid ice. In prolonged, extreme cold, even moving water can freeze inside an uninsulated pipe, so a drip alone is not adequate protection. If you see reduced flow, frost on the pipe, or suspect a freeze has begun, stop relying on a drip and take active thawing or professional-plumber measures.
• Warning sign: it becomes your only or long-term strategy. Running hot water continuously wastes both water and the energy needed to heat it. A dripping hot faucet can noticeably increase your water and energy bills over a multi-day cold snap, and it does nothing to fix the underlying vulnerability. If a cold-water line serves the same fixture or is the one actually at risk, dripping hot water is an unnecessary expense.

Pros and Cons

Pros

• Moving water is harder to freeze than standing water. A steady trickle keeps water circulating through the pipe, which can reduce pressure buildup from ice and lower the chance of a complete blockage during brief cold spells. This simple action costs nothing to set up and requires no tools.
• It can protect a hot-only branch. Some fixtures or pipe runs are served almost entirely by the hot-water line. Dripping that faucet directly protects the most exposed segment and may be the simplest way to keep water flowing through that specific line until permanent repairs are made.

Cons

• It raises water and energy costs. A hot-water drip continuously draws cold water into your water heater, forcing it to cycle and reheat. Over several days this can add up, making it more expensive than dripping cold water or installing insulation.
• It can create a false sense of security. Because hot water cools quickly once it leaves the heater, the temperature advantage at the faucet is small. A drip may not prevent freezing in severe, sustained cold, and relying on it can delay more effective fixes such as pipe insulation, heat tape, or air-sealing.

Decision Checklist

• Which pipe is actually at risk? Determine whether the vulnerable line is the cold supply, the hot supply, or both. If only the cold line is exposed, drip the cold faucet; if both are exposed, dripping the cold line may protect both if they run together, but a hot drip may be added for extra protection on the hot branch.
• How cold will it get, and for how long? Brief dips to just below freezing are different from week-long sub-zero cold snaps. The colder and longer the freeze, the more you should prioritize insulation, heat tape, or draining pipes rather than relying solely on dripping.
• Have you done the free fixes first? Before committing to a continuous hot-water drip, open cabinet doors to let room air reach pipes, seal obvious drafts, keep the thermostat steady day and night, and disconnect hoses from outdoor spigots. These steps often remove the need to drip at all.

Alternatives to Consider

If a hot-water drip feels wasteful or risky, several other options may be more effective. Insulate exposed pipes with foam tubing, especially in unheated attics, crawl spaces, and exterior walls. Install electric heat tape with a thermostat on high-risk runs, following manufacturer safety instructions carefully. Keep interior doors and sink cabinets open so warm household air can circulate around plumbing. Maintain a consistent thermostat setting rather than lowering it at night during a freeze. For outdoor faucets, shut off the interior valve if one exists, drain the line, and install frost-free hose bibs. In vacation homes or during extended absences, consider draining the entire plumbing system and shutting off the main water supply. For fixtures where the cold line is the concern, dripping cold water is usually the more economical choice.

Final Recommendation

For most households, the better default is to drip the cold-water faucet fed by the most vulnerable pipe, while also insulating pipes, sealing drafts, and keeping the heat steady. Drip hot water only if the hot-water line alone is exposed or isolated and you cannot immediately insulate or redirect heat to that branch. Treat any drip as a temporary, supplemental tactic rather than a permanent solution. If your home has a history of frozen pipes, you live in an extremely cold climate, or a pipe may already be frozen, consult a licensed plumber for a professional assessment.