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What To Do When A Water Heater Gets Frozen?

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

It’s tough to imagine the harsh winter season without a constant stream of hot water. This situation can worsen if your water heater completely freezes without any prior warnings.

Most people living in warmer parts of the world do not have to worry about the harsh winters, but homeowners living in heavy winter areas should always be prepared for frozen water heaters.

Thus to help you overcome this issue, we have sketched out a detailed article that focuses on taking the proper steps. We also talked about the most pressing questions that all water heater owners should know about.

Reasons for a frozen water heater?

What are the reasons for a frozen water heater

The most obvious reason for a frozen water heater is the drastic drop in the temperatures. Freezing of your water heaters can initiate soon after the area is covered with freezing temperatures.

Another big reason for a frozen heater is the constant power outage. The combination of these two factors can very quickly jam up your water heating system within a few hours.

Unattended open pipes can also trigger freezing. These pipes can sometimes over-expand and start to leak. The leaks can even turn into bursts which interrupt and damage the entire heating system.

Sometimes the main reason for the issue is the heater’s inability to perform optimally. Older models and heaters that run without any constant maintenance can cause freezing. Lastly, a system overload can also force the heater to work overtime, finally putting the unit at a frozen standstill.

A few reasons include:

  • Drastic temperature drop
  • Constant power outage
  • Unattended pipes
  • Unmaintained heaters
  • Sudden system overload

Steps to tackle the frozen water heater?

If you spot a frozen water heater in your basement, we request you to follow these steps.

These nine basic steps can help you recover the water heater from its frozen state to a normal working one within a few hours.

Step 1: Checking the damage

damage on plumbing

Inspecting the water heater should be your first and foremost instinct. It would be best to check whether the entire heater is frozen or just the pipes leading in and out of the heater.

Touching the heater from the outside will give you a decent idea about its degree of seriousness. This issue is more prevalent in tank water heaters as compared to tankless water heaters. Tankless water heaters (see also ‘How To Winterize A Tankless Water Heater‘), however, have a high chance of frozen vents and pipes.

Your next step is to look for any pipe bursts. Water expands while freezing, and thus to accommodate that expansion, some water flows down to the pipes causing outbreaks. Figuring out a way to turn off your water valve can be a good idea before defrosting your pipes.

Step 2: Shutting off the system

Start shutting off your water or gas supply as soon as you notice a frozen unit. If the problem is plain frozen pipes, you can skip this step.

Kindly start disconnecting your water heating unit before it thaws. You can also place the water heater in some out-of-the-way area to avoid cleaning up the mess.

Displacing the heater will also keep your other appliances safe from any sudden bursts while the unit thaws.

Step 3: Warming the area

Turning on a space heater can prove to be a good idea as indirect heat will help speed the process.

The warmer the area, the faster your frozen water heater will melt the ice buildup. We do not recommend spot heating as it can cause damage to your water heater.

Step 4: Draining your water heater 

draining water heater

Once ice freezes in your water heater, it tends to damage the internal plastic components. You can prevent this by slowly draining the water heater while separating the water from the heater.

Using the valves near the hot and cold lines can be an excellent way to drain the tank. We highly recommend draining your tank water heater before leaving your house for an extended winter vacation.

Draining the water heater manually:

  • Double-check if the gas and water supply is off.
  • Turn off the temperature control of the system.
  • Ensure that you have disconnected all the power running to the heater.
  • Opt for a big bucket to catch all the drained water.
  • Slowly remove the drain caps from the cold and hot isolation valves.
  • Open the valves and remove the cold water inlet filter.
  • Initiate the draining process.

Step 5: Opening an air release valve.

Slowly allow the air to get back in your water heater tank by opening an air release valve or hot faucet.

This step will allow the remaining accumulated water to flow out as soon as it turns into liquid.

Step 6: Insulating the external pipes.

insulate external pipes

Homeowners usually forget how important it is to insulate their pipes in cold weather. It doesn’t matter if your system is tankless or tank; the external lines are equally at the risk of freezing.

Apart from providing extreme protection from freezing, insulation also prevents heat loss, thus making your water heater more energy-efficient and faster. You can also keep the internal pipes warm by using a central heating system every day for a short time.

Pipe insulation can be an expensive task, but proper materials and a decent cover-up will surely keep your hot water system from freezing in the winters. Polyethylene wraps or fiberglass insulation are excellent materials to insulate your pipes without spending a hefty amount.

Step 7: Cleaning the exhaust and intake vents.

Another crucial step is to check your intake and exhaust vents. Cleaning them will surely avoid any future blockages or freezing scenarios.

Frozen vents and pipes are at the most high risk of bursting. Sometimes even issues like small leaks can cost significant damage in the long term.

Step 8: Keeping a steady and uninterrupted power source.

Once your unit returns to life, you need to ensure that the system gets an adequate power supply.

This power supply is essential for models that have an inbuilt freeze protection system. We advocate using a decent battery backup for places and houses that suffer constant power outages.

Step 9: Installing your water heater in a warmer part of the house.

installing wqater heater

This advice may not be the easiest solution, but we recommend moving and installing your heating system to a warmer part of the house.

Moving the unit to a balmy space will less likely freeze your water heater. A makeshift outdoor shelter can also work well to keep the area highly insulated. 

Following these nine steps would help you get rid of the frozen water heating unit. You can surely avoid a few steps as per your convenience and requirements. 

How do you know if the water pipe bursts?

Water pipe bursts are notoriously common in frozen water heaters. Most of the time, you will see tiny cracks followed by a leaky steady stream of water.

These pipes need to be replaced immediately to avoid any extra pressure on your water heaters. Sometimes minor fractures can be almost difficult to detect during the initial checking. But soon, you will notice damp spots behind your wall or ceiling that will conform to the pipe bursts.

Replacing such pipes should be your number one priority. We recommend checking your lines every other week in all seasons for an efficiently working water heating system.

Should frozen pipes thaw on their own?

warming up frozen pipes

No, it is certainly not the wisest decision when it comes to thawing frozen pipes. Keeping them unattended can build up extreme pressure, which bursts the lines open.

Leaving them on their own will cause massive water damage resulting in repair fees worth thousands of dollars. You can tackle the situation slowly by using electronic devices like heating pads, hairdryers, or heating cables to warm up the pipes.

Even warm towels work excellent when wrapped around the circumference of the lines. Avoid using open-flame devices like a blowtorch or propane heaters near your frozen pipes. 

How to determine whether you have a frozen pipe?


The most obvious sign is a restricted water flow through all or a single faucet. Sometimes, a frozen pipe pushes a weak stream of water that can help you identify the issue.

The frozen pipe will often make a loud gurgling sound, indicating the problem. A colder tube to the touch is yet another sign of an icy pipeline.

Can water heater pipes freeze in one night?

determine frozen pipes

Yes, water heater pipes can undoubtedly freeze overnight, depending on the temperature. The lower the temperature, the quicker they tend to freeze. However, well-insulated pipes do not freeze as quickly as unprotected pipes.

Preventive measures to avoid frozen water heaters

Tankless water heater

Tankless water heaters have a low chance of freezing as compared to standard tank water heaters. These water heaters do not need any special protection during colder seasons.

As long as the heater is connected to the power supply, it will seldom freeze. However, you should avoid disconnecting the heater system during lower temperatures.

Disconnecting will indeed expose the heater to freeze from the inside. In case of emergencies, ensure that your tankless water heater is completely drained before you disconnect it from the power hookup.

Tank water heater

A traditional storage-style water heater requires heavy protection during the harsh winter months. We highly recommend inspecting the entire tank and system before the winter season approaches.

The inspection should cover leaks, temperature pressure releasing valve’s functionality, and a fully functional sacrificial anode rod. Consider cleaning the tank if you notice any sediments or calcification at the end of the tank.

Finally, see to it that your storage tank has an “R” value of over 24. If your tank is warm to touch or displays an R-value under 24, we recommend insulating your tank.

Running a trickle of water

prevent your pipes from freezing

Running water is an excellent trick to prevent your pipes from freezing during the winter season. To prevent your pipes from freezing internally:

  1. Run water at 0.1 to 0.2 gallons per minute through the hot side.
  2. Ensure that it runs through the furthest fixture with gas off. The water will keep running through the heating system, thus minimizing the chances of freezing.

Regular maintenance

The key to having a fully functional water heater is constant preventative maintenance. Do not forget to change any damaged or old parts and consider flushing your water heater before winter.

Pipe insulation

Pipe insulation is one of the most practical and easiest ways to tackle frozen pipes and systems. The insulation process is pretty straightforward; even people with little knowledge of insulation can successfully carry out this task. 

Installing freeze protection solenoid valves

Water heater owners can now install special freeze protection solenoid valves to keep the system running during the colder months. These valves automatically open while releasing water from your tank unit during any sudden electricity outrage.

Covering the intake and exhaust vents

Place a sturdy cover on the intake and exhaust vents to avoid leaves, dirt, dust, debris entering the ducts. This covering will prevent the vents from flow issues that can worsen during the winter season.

Purchasing heaters with in-built freeze protection

Most tankless water heaters now have special built-in freeze protection that discourages the system from freezing as long as a steady power is pumped through the water heater. Buyers can find this feature in water heating systems of premium ranges.


We assume our detailed step-by-step guide provided you with some valuable insight into tackling your frozen water heater.

Apart from the solutions, we recommend that water heater owners actively participate in regular maintenance practices. They should also pay attention to the various preventative tips before the winter season approaches.

Lastly, consult your local HVAC company or professional plumbers if your water heater still showcases a few signs of freezing. Consulting such professionals before every winter season will indeed save you the trouble of unexpected water heater issues.

Reference articles:

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Charlie Hardcastle


On Key

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