The Texas Homeowner’s Guide to Preventing Frozen and Burst Pipes

To prevent frozen and burst pipes in Texas, drip faucets slowly during a hard freeze, open cabinet doors so warm air reaches under-sink plumbing, keep the heat on even if you are away, and disconnect garden hoses. Know where your main water shutoff valve is so you can close it if a pipe bursts.

Why Some Texas Homes Are Vulnerable to Winter Freezes

In many North and Central Texas homes, especially older ones, some plumbing runs through attics, exterior walls and other spaces outside the insulated, heated part of the house. Common places where pipes can be exposed to cold include:

• Unconditioned Attic Spaces: In slab-on-grade homes across Dallas-Fort Worth, Austin, and San Antonio, PEX and copper plumbing runs are sometimes routed through attic joists above the insulation, where they can be exposed to outdoor-like temperatures. When outdoor temperatures drop into the teens, attic ambient air can quickly drop below 28°F.
• Exterior Wall Pipe Routing: Kitchen sink supply lines and bathroom supply branches are sometimes routed inside exterior walls with limited insulation, which can leave them exposed to cold.
• Slab Foundation Penetrations: Where water service enters through concrete foundation slabs, cold bridging can occur if perimeter foundation walls are directly exposed to icy northerly winds.

During the February 2021 winter storm (Uri) and later freeze events, a large number of Texas homes suffered serious water damage from burst pipes. Understanding your home's structural piping layout is the foundational first step to preventing a multi-thousand-dollar burst pipe catastrophe.

What Temperature Do Pipes Freeze? Understanding the Danger Thresholds

Water expands by approximately 9% in volume when transitioning from liquid to solid ice. In an enclosed plumbing pipe, this crystalline expansion creates immense hydrostatic pressure—about 4,000 PSI in one instrumented copper-pipe test—compared with the 40 to 80 PSI a household supply line normally carries. That is enough to split rigid pipe.

Key temperature rules every homeowner should track:

• 32°F (Freezing Point): Outdoor frost can form. Plumbing inside the heated part of the house is usually safe, but pipes in unheated or poorly insulated spaces can begin to freeze if temperatures stay at or below freezing for an extended period, especially in wind.
• 28°F (The Danger Zone): At around 28°F (-2°C), uninsulated pipes in unheated crawl spaces, exterior hose bibs, and vented attics can begin to form interior ice blockages if the cold lasts long enough. How quickly this happens depends on insulation, wind and how long temperatures stay low.
• 20°F and Below (Severe Emergency Threshold): As a rough guide, at 20°F (-7°C) or lower the risk rises sharply: even insulated pipes in exterior walls and unconditioned attics can freeze unless you keep water moving with a slow drip, keep interior heat on, or otherwise protect them.
• The Wind Chill Factor: Wind speeds up heat loss from pipes in drafty areas. A cold draft blowing through a vent or gap directly onto exposed pipe can make it freeze sooner than in still air at the same temperature. Wind cannot cool a pipe below the air temperature, but it gets it there faster.

The 4-Step Action Plan Before the Temperature Drops

When a hard freeze warning is forecasted, execute these four defensive protocols immediately:

• The Faucet Drip Protocol: Select the faucet located furthest from your main water service entrance, as well as any faucet fed by an exterior wall line. Drip both hot and cold lines at a slow, steady trickle to help relieve pressure and keep water moving. Follow your local water utility's guidance, since conservation requests can change during widespread freezes.
• Open Vanity & Kitchen Cabinet Doors: Allow warm 68°F–70°F conditioned indoor air to circulate directly around under-sink plumbing and trap assemblies.
• Maintain Continuous Indoor Heat: Keep your heat on during a freeze, even if you are away from home, and avoid setting the thermostat low; a steady, moderate indoor temperature is safer for pipes than letting the house go cold.
• Disconnect Outdoor Garden Hoses: Water trapped inside an attached hose can freeze and expand back into the exterior wall valve, which can split the pipe. Disconnect all hoses and install foam insulating faucet covers.

Emergency Preparedness: How to Shut Off Your Main Water Line in 60 Seconds

When a frozen pipe bursts, it does not typically leak while frozen solid. The real catastrophe often happens when the ice melts, because pressurized water can pour through the split into your ceilings, walls, and flooring until the main valve is shut off.

Every homeowner must know their main shutoff valve location:

• Interior Ball Valve: Typically a red or yellow quarter-turn lever in the garage, utility closet, or near the water heater. Turn it 90 degrees perpendicular to the pipe.
• Street Meter Box: Located in an underground utility box near the street curb. The valve in that box is often the utility's equipment, and some utilities do not allow customers to operate it, so check with your water utility before using a meter key. Your main shutoff valve at the house is the first choice.

Frequently asked questions