Preventing residential water pipes from freezing is a significant concern for homeowners during cold weather. Water expands as it solidifies, and this expansion inside a rigid pipe can cause a rupture. A burst pipe can lead to substantial flooding and property damage, with repair and cleanup costs often exceeding $10,000. Taking proactive steps during a freeze event is the most effective way to avoid this plumbing disaster.
The Physics of Flow: Why Continuous Movement Stops Freezing
The primary risk from freezing water is the pressure that builds behind an ice blockage. When water freezes, it expands. If an ice plug forms between the water supply and a closed faucet, the continued expansion has nowhere to go. This trapped pressure causes the pipe to burst, often at a weak point far from the ice itself.
A slow, steady drip from a faucet relieves this hydraulic pressure, providing an escape route for the expanding water. Flowing water is also more resistant to freezing than stagnant water. The continuous movement introduces slightly warmer water from the underground main supply, which helps keep the temperature within the pipes above the freezing point.
Determining Which Water Line to Open
Focus on dripping the cold water line at any faucet connected to pipes that run through unheated or exposed areas, such as those along exterior walls. The cold water line is the most vulnerable because it does not benefit from the residual heat of the water heater. A slow trickle is sufficient for this preventative measure.
If the faucet is in a particularly cold location where both hot and cold lines are routed near each other, dripping both lines may be a safer strategy. The flow should be minimal, aiming for a drip rate of approximately one drop every three seconds. This rate is enough to relieve pressure and encourage movement without wasting excessive water. Dripping the faucet furthest from the main water source is also recommended, as this draws water through the maximum length of the plumbing system.
Immediate Steps Beyond Dripping
While dripping faucets helps, other actions are necessary to protect pipes from cold temperatures. Open the cabinet doors underneath sinks, particularly those against exterior walls, to allow warmer indoor air to circulate around the enclosed plumbing. This introduces heat from the room to the pipes, which are often shielded from the home’s internal warmth.
Maintain a consistent temperature in your home, setting the thermostat to a minimum of 55 degrees Fahrenheit, even if you are away. Lowering the temperature excessively allows the air within walls and unheated spaces to drop rapidly toward freezing.
Disconnect and drain all exterior garden hoses from hose bibs and turn off the water supply to those spigots.
Safe Thawing Procedures If Freezing Occurs
If you turn on a faucet and only a trickle or no water comes out, a pipe has likely frozen. Locate the main water shut-off valve and close it immediately to prevent flooding when the pipe thaws or if it has already burst. Keep the frozen faucet open, as this allows steam and melting water to escape and relieves pressure within the pipe.
For an accessible frozen pipe, you can attempt to thaw it using a safe, gradual heat source. Apply heat with a hair dryer, an electric heating pad wrapped around the pipe, or towels soaked in hot water wrapped around the affected section. Start applying heat closer to the faucet and work backward toward the blockage to allow the water to move out.
Never use an open flame device like a propane torch or a kerosene heater, as this poses a fire hazard and can cause the pipe to burst. If the frozen pipe is inaccessible, or if a rupture is suspected, contact a licensed plumber immediately.