How to Protect Pipes Before a Dallas Freeze

Dallas gets few freezing days, and that is the problem. Houses here are built mostly for summer heat, so supply lines run through attics, exterior walls and garages with little protection, and the owners rarely think about it until a forecast turns bad. The good news is that the preparation is cheap, takes an afternoon and works best done a week ahead.

What the weather record shows

The National Weather Service’s 1991–2020 normals for DFW Airport list 29.2 days a year with a minimum temperature at or below 32°F. January averages 10.6 of those days, December 8.1 and February 6.2. March and November add a couple each, and October about a tenth of a day. Most winters, then, are a scatter of short cold nights.

The long events are what damage plumbing. NWS Fort Worth’s summary of February 2021 records two stretches at DFW Airport: 93 consecutive hours at or below freezing, from 5 pm on February 9 to 2 pm on February 13, then 139 consecutive hours from 5 pm on February 13 to noon on February 19, with a brief rise to 33°F in between. The low was −2°F on February 16. The page describes the second stretch as tying for fifth place for the most consecutive hours below freezing at the airport.

One event proves nothing about your house, and the airport is a single point. It does show what a Dallas building has to survive when a freeze does not break overnight.

Where pipes freeze first

• Attics. Supply lines and water heater connections above the insulation sit in air as cold as the outdoors.
• Exterior walls. Kitchen, bathroom and laundry lines in a wall with little insulation, especially behind a sink on the north side.
• Garages and utility rooms. Unheated, with gaps under the door.
• Crawlspaces. Lines under a pier-and-beam floor, exposed to wind through vents.
• Outdoors. Hose bibs, irrigation backflow assemblies and any pipe run along an exposed wall.

A prep list by location

The week before a hard freeze

1. Walk the attic with a light. Look for bare supply lines, gaps in insulation around pipes and any pipe that touches the roof deck.
2. Close air gaps. Gaps around pipes where they pass through exterior walls and under garage doors let cold air straight onto the plumbing.
3. Insulate what you can reach. Foam sleeves are inexpensive. Seal the seams with tape.
4. Test the main shutoff. See the post on finding and testing it.
5. Handle the outside. Disconnect and drain hoses, shut off and insulate faucets that are not frost-proof, and drain or shut down irrigation.
6. Check the heat. A furnace that fails in a long freeze is a plumbing problem too.

During the freeze

Keep the house heated, including rooms you rarely use. Open cabinet doors on exterior walls so room air reaches the pipes, and let a faucet fed by an exposed line run as a thin stream. Check ceilings and walls once or twice a day. If a faucet runs weak or stops, assume ice and act on it before it splits: see the guide to a frozen pipe.

An attic walk-through you can do in half an hour

1. Go up in daylight, with a flashlight, stepping only on framing.
2. Find every pipe. Supply lines to bathrooms and the water heater are the usual ones.
3. Check coverage. Is the pipe under insulation, or lying on top of it? A pipe above the insulation is the most exposed.
4. Look for gaps and drafts around the pipe, vents and the attic hatch.
5. Photograph what you find so you can compare next year and show a plumber.

Heating cable, which Triple-I mentions for attic and crawlspace pipes, should be a product made for the purpose and installed per its instructions. Misused, it is a fire risk.

If the power goes out

IBHS notes that plumbing and interior sprinklers may freeze in extreme cold, particularly during power outages. When heat is gone for many hours, the options are to close the main and drain the lines, or to keep the pipes warmer with insulation and heat sources that are safe indoors. Do not use a generator indoors or in an attached garage; see the safety guide. If the house will go unheated for a long period, closing the main and draining the lines is the more reliable choice.

Rentals, townhomes, garages and irrigation

The general list does not cover everyone. A few situations need their own attention.

• Renters. You may not be allowed to alter plumbing, but you can ask the landlord to insulate exposed lines, ask where the shutoff is and know who to call after hours. Open cabinet doors and keep the unit heated. Tell the landlord before a long trip.
• Townhomes and condos. Shared walls help, but end units and units over garages are more exposed. A burst line in a vacant neighbor’s unit becomes your problem. Know your association’s emergency contact.
• Garages. Triple-I suggests considering insulating garages and other unfinished areas to keep pipes from freezing. Water heaters, washer hookups and supply lines run through many garages. Close gaps under the door and keep the washer’s valves in view.
• Irrigation. Backflow assemblies sit above ground and are exposed. Ask the installer how to shut down and drain the system for winter, and shut the supply off inside the house.
• Interior fire sprinklers. IBHS notes they may freeze in extreme cold. If you have them, ask the installer what to do.

What your policy may require

The Texas Department of Insurance says many policies will pay for damage caused by a frozen pipe that burst, but there may be limitations. Read yours for conditions such as keeping the house heated or taking reasonable steps to prevent freezing, and ask your agent what counts. If a pipe does burst, the first hour plan is the place to start, and the burst pipe cleanup page covers the work afterward.

Read about frozen and burst pipe cleanup →

This article is general information from the Dallas Flood Guard editorial team. It is not medical, legal, engineering or insurance advice. Sources are linked above. See the editorial policy for how posts are researched and corrected.