How to protect a water heater from freezing?

Author: Brandt Schmidt  |  Last update: Monday, December 29, 2025

Ways To Prevent Frozen Water Heaters
  1. Drain the Unit. ...
  2. Insulate the Pipes. ...
  3. Keep the Heater Warm. ...
  4. Plug the Heater. ...
  5. Use a Recirculation System. ...
  6. Check the Temperature. ...
  7. Inspect the Relief Valve. ...
  8. Get a Freeze-Proof Heater.

At what temperature will a water heater freeze?

A large number of tankless water heaters have built-in freeze protection that works in temperatures down to -22 degrees F. The next tankless water heater that you buy should have this, especially if the only option is to install it outside. Different brands use different freeze-prevention methods.

Will a water heater in the attic freeze?

Location Matters. The location of the water heater plays a crucial role in whether it will withstand low temperatures. If installed in an unheated space such as a garage, attic, crawlspace, or poorly insulated basement, the likelihood of the water heater freezing is higher.

Will a water heater burst if it freezes?

Any water heater can freeze if water is left inside it

Tank water heaters usually hold between 40 and 55 gallons and can require electricity. So when the power goes out in freezing temperatures, the water eventually can freeze, expand and burst the storage tank.

How do you winterize a hot water heater?

Turn off your water shut-off valve inside or outside of your home. After you've ensured it is fully turned off, unplug or turn off the fuel that's powering your heater. To be sure it's switched off, check the pilot light. Now you can drain the remaining water from the tank using a bucket or hose.

How to Prevent Your Hot Water Heater from Freezing

How do I freeze proof my water heater?

Ways To Prevent Frozen Water Heaters
  1. Drain the Unit. ...
  2. Insulate the Pipes. ...
  3. Keep the Heater Warm. ...
  4. Plug the Heater. ...
  5. Use a Recirculation System. ...
  6. Check the Temperature. ...
  7. Inspect the Relief Valve. ...
  8. Get a Freeze-Proof Heater.

Should I drain my water heater before a freeze?

Unless your pluming is PEX, when it freezes it will burst. The proper procedure is to turn off the water and open the heater breaker. Then open all faucets and flush all toilets. Open the low point drain, usually the water heater drain and let all water drain.

What do you do when your hot water heater is frozen?

If the issue is isolated to the water heater, turn off the power. Next, turn off the gas and water shutoff valves and disconnect the unit. Relocate it to a warm room or use a space heater if you can't move the water heater away from a chilly area. Once the unit starts warming up, the ice should melt.

How do you know if your water heater is about to burst?

7 Warning Signs of Water Heater Explosion
  • Leaking Pressure Relief Valve. ...
  • A Consistent Popping Noise. ...
  • Rotten Egg Odor. ...
  • Brown Water. ...
  • Gas Leak. ...
  • Improper Bad Installation. ...
  • Neglecting Routine Maintenance.

Will my pipes freeze if my water heater is off?

Your Pipes Could Freeze and Burst

If you turn off your water heater, your interior temperature will drop, leaving the water in your pipes susceptible to freezing. When the water in your pipes freezes, it expands and becomes ice.

How to keep a heater from freezing?

How to Prevent Your Furnace from Freezing
  1. Place a small mound of rock salt outside your home right below the exterior opening of the condensate drain line to prevent ice formation.
  2. Insulate the condensate drain line and floor drain.
  3. Wrap the interior condensate drain line in heat tape.

How do I know if my hot water pipe is frozen?

No water or a slow trickle when a faucet is used. Whistling and banging coming from pipes, or strange bubbling sounds when you flush a toilet. Dampness, puddles, or rings on drywall or ceilings—signs of an urgent issue.

Should I wrap my water heater in the garage?

With colder water coming into the home and many water heaters located in parts of the house that tend to be exposed to colder temperatures (be it a garage or an unfinished basement), adding insulation to the water heater can help protect the appliance and help it perform better.

What temperature is unsafe for water heater?

120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting. Most experts agree that anything below 120 degrees creates a risk for bacteria to develop inside your water heater from stagnant water, such as legionella that causes Legionnaire's disease.

How cold does it have to be to flash freeze hot water?

For boiling water to immediately freeze in mid air, the outside temperature needs to hit well below zero. Also, cold water will not freeze as boiling water will in those conditions. Some recommend -42 degrees, while other recommend -21 degrees.

How common is a hot water heater burst?

According to the Insurance Institute for Business & Home Safety, the average storage-type water heater only lasts about 10 years. By the 9-year mark, more than 40 percent have burst, and just 6 years after setting up your new model, there's still a 15 percent chance it will explode all over your basement.

Why is my hot water not working but cold is?

Possible Issue: One of the most common culprits for this predicament is a malfunctioning differential valve. This valve is responsible for controlling the flow of hot and cold water in your plumbing system. When it's not functioning correctly, it can lead to an imbalanced water supply, leaving you with cold water only.

What is the average life of a water heater?

Based on the manufacturer's suggested service life, the average life expectancy of a water heater is about 8 to 12 years. That varies with the location and design of the unit, quality of installation, maintenance schedule and water quality.

How do I prepare my water heater for freezing?

The simple solution? In your have a tanked system be sure to insulate your water heater and your pipes—pipes only if you're dealing with a tankless model. Insulating pipes can keep water from freezing when the temperatures drop below the 30s.

Should you turn off the water heater during a freeze?

Frozen pipes can cause serious water damage to your home. The warm water your heater produces will continue circulating your system and prevent the leaks, cracks, and burst pipes that freezing can cause. Leave your water heater on to avoid frozen pipes and accompanying damage to your property.

What to do with hot water heater during freeze?

Drain the water heater. Disconnect the power and gas supply. Shut off the cold water supply.

Should I turn off my hot water heater if my pipes are frozen?

Frozen pipes can cut off your home's water supply and cause damaging leaks. In many cases, the help of a plumber is needed to resolve the problem. To prevent further damage, it is generally recommended that you turn off your main water supply valve and your water heater until repairs have been made.

When should you not flush a water heater?

(Don't worry! It doesn't come out of your faucets.) If neither you nor a professional have flushed your water within the last five years, Water Heaters Now recommends not flushing it yourself. If you flush a water heater that already has a significant sediment buildup, it can actually cause more problems.

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