How to prevent frozen pipes in an East Tennessee cold snap

Key takeaways

• Pipes in unheated spaces freeze first: crawlspaces, exterior walls, garages and outdoor spigots.
• On the night of a hard freeze, let a faucet on an exposed line drip, open the cabinet doors under sinks, and keep the thermostat at one setting day and night.
• Disconnect garden hoses and close crawlspace vents before the first freeze, not during it.
• If you leave home in cold weather, keep the heat on. The Red Cross suggests no lower than 55°F.
• If a pipe does freeze, read how to thaw frozen pipes before you reach for a heat source.

Why pipes freeze

Water expands as it turns to ice. The ice itself is a problem, but the bigger danger is pressure building between the ice plug and a closed faucet. That pressure is what splits the pipe, often a few feet from where the ice sits. You may not see the damage until the ice melts and water starts to flow.

Winters in the Tri-Cities are mild most days, so pipes that would be buried or insulated in colder places are often left bare. Then a cold snap arrives. At the Tri-Cities Airport the typical last freeze of spring falls around April 16, based on 1991 to 2020 data from NOAA and the National Weather Service. Freeze risk is not only a January problem. It runs well into spring.

What freezes first

Walk through your house and look for water lines in these places:

• Vented crawlspaces. If your house has one, the pipes near the vents and along the outer foundation wall are the most exposed.
• Exterior walls. The sink on a north-facing kitchen wall is a classic. The pipe sits between the cold outside and the warm room, so it gets little heat from either.
• Unheated garages and sunrooms. Washer hookups and water heaters in garages are common trouble spots.
• Outdoor spigots. A hose left attached holds water in the faucet and the pipe behind it.
• Basements with an outside wall, especially finished ones where the pipes are hidden behind drywall.

The Red Cross says the pipes most at risk are those in unheated areas, such as kitchen cabinets, garages and basements.

Do these in the fall, before the first freeze

1. Disconnect every garden hose. Drain it and store it. If your spigot has a shutoff valve inside the house, close it and open the outdoor spigot to drain the line.
2. Close the crawlspace vents for the winter, and open them again in spring. Check that the vent covers are intact. Missing or broken covers let cold air blow straight onto the pipes.
3. Insulate exposed pipes. Foam sleeves are sold at hardware stores and slip over a pipe in a few minutes. Cover the pipes you can reach in the crawlspace, garage and basement.
4. Seal air leaks near pipes. Gaps where a pipe enters the house let cold air reach the line. Caulk or spray foam fills small gaps.
5. Find your main shutoff. Make sure it turns. If a pipe ever bursts, it is the first thing you will need. The emergency plumber page explains where to look.
6. Think about a permanent fix. A plumber can swap an ordinary spigot for a frost-free one, add heat tape to a problem line, or move a pipe out of an exterior wall. If the same pipe freezes every winter, a permanent fix is worth asking about.

About heat tape

Heat tape (also called heat cable) is an electric cable that warms a pipe. It can be a good fix for a line that keeps freezing, but treat it with care:

• Use only a UL-listed product made for pipes, as the Red Cross advises, and follow the maker's directions for your type of pipe.
• Plug it directly into an outlet. Don't use an extension cord.
• Replace tape that is cracked, frayed or scorched.
• Don't wrap it over itself or cover it with materials the instructions don't allow.

If you aren't sure the tape is safe, have a licensed plumber or electrician look at it.

The freeze-night checklist

Print this list and use it on the evening before a hard freeze.

• Hoses are off the spigots.
• Crawlspace vents are closed and their covers are intact.
• Cabinet doors under sinks on exterior walls are open (kitchen and bathrooms).
• A cold-water trickle is running from a faucet on the most exposed line.
• The thermostat is set to one temperature and left there day and night.
• The garage door is closed if water lines run through the garage.
• Anyone who will be away has the heat set to 55°F or higher.
• Everyone in the house knows where the main water shutoff is.
• A neighbor or family member can check the house if you are traveling.

The trickle, the open cabinet doors and the steady thermostat all come from the Red Cross's frozen-pipe guidance. Moving water is much harder to freeze, and open doors let room air reach the pipes behind them.

When you're away

A house that sits empty in January is where small problems become big ones, because nobody is there to notice.

• Keep the heat on. The Red Cross suggests no lower than 55°F.
• Ask someone you trust to check the house every day or two during a hard freeze.
• For a long absence, you can shut off the main valve and drain the lines. Close the main, open the lowest faucet in the house, and turn off the water heater first so it doesn't run dry. A plumber can show you how, especially if your home has a well or a sprinkler system.
• Remember that a power outage stops the heat. Without it, pipes freeze faster.

Vacant homes and rentals

Empty houses, rentals between tenants and second homes freeze more often than occupied ones, because the heat is low and nobody is checking. If you manage one:

1. Decide whether the water stays on or is shut off for the winter. Leaving it on only works if the heat stays on and someone checks the house.
2. If you shut it off, drain the lines and the water heater.
3. Write the plan down and keep a plumber's number on the same page as the shutoff location.

Crawlspaces: what helps

Crawlspace pipes are a common place to freeze, so they deserve a closer look.

• Close the vents in winter, and check the vent covers.
• Insulate the pipes themselves, not only the floor above. Insulation slows heat loss but does not add heat. In a long hard freeze, an insulated pipe in an unheated space can still freeze.
• Ask before blocking air to a gas appliance. A furnace or water heater in the crawlspace needs combustion air.
• If you see standing water in the crawlspace, that is a separate problem. The water damage restoration page covers it.

Signs a pipe is freezing

• A faucet that runs slowly or only trickles when it normally runs strong.
• Frost on a pipe you can see.
• A toilet that is slow to refill.
• Odd smells from a drain.

If you notice any of these on a cold day, don't wait. Open the faucet, find the cold spot, and follow the steps in how to thaw frozen pipes.

When to stop and call a plumber

Call a licensed plumber if:

• You can't find or reach the frozen section.
• Water is coming from a pipe that has split. Shut off the main first. See burst pipe repair.
• The same pipe freezes every winter.
• You have no water, and the problem may be outside the house.
• The frozen line serves a well pump, a sprinkler system or a boiler.

The frozen pipes page explains what a plumber looks at first.

If you only have ten minutes

Do these four things first, in this order: close the crawlspace vents, take hoses off the spigots, open the cabinet doors under the kitchen and bathroom sinks on exterior walls, and set a cold trickle running at the faucet farthest from where the water enters the house. Then write the main shutoff location on a sticky note by the door. None of it needs tools, and together these steps cover the most common freeze points.

Safety

• Never use an open flame, a torch, or a charcoal or propane heater indoors to warm a pipe.
• Keep space heaters at least 3 feet from anything that can burn, plug them directly into a wall outlet, and turn them off when you leave the room or go to bed. This is NFPA and U.S. Fire Administration guidance.
• If you smell gas, leave the house and call your gas utility from outside.