How Long Do Water Heaters Last? Signs & Cost to Replace


Water Heater

Water heaters are an essential part of our everyday lives. We use water heaters every day and often take advantage of providing hot water when we need it. Often we don’t prepare for replacement, and when a water heater quits, it can become a shock to us and our wallet. 

Part of preparing and budget for a water heater replacement is knowing how long a water heater will last.

So, how long does a water heater last? The typical lifespan of an electric water heater is 10 to 15 years. A gas water heater has a shorter lifespan of 8 to 12 years on average. Tankless water heaters can last up to 20 years. 

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Can a water heater last 20 years? A well-maintained gas or electric water heater can last up to 20 years or more provided the water heater has been properly maintained. This includes replacing the anode rod every 2-3 years to protect the inner lining of the tank to keep it clean and in good condition.

In this article, we will focus on tank-style gas and electric water heaters. Many factors go into determining how long a water heater will last. The number one factor that can extend the water heater’s lifespan is water heater maintenance.

Many of these factors have to do with proper maintenance, which, if done routinely, can extend the life of a water heater for several years. However, if the water heater is not maintained well, you can expect the lifespan to be shorter, and you could risk sudden failure or worse damage to your house. 

Even inexpensive water heaters can outlast more expensive models provided it’s properly maintained.

Most inexpensive water heaters come with a 6-year manufacturer warranty. However, some better quality models can have manufacturer warranties upwards of 10 to 12 years. In contrast, some high-end models can have lifetime warranties on the water heater. 

Water heaters with a fiberglass tank tend to last considerably longer than water heaters with steel tanks. Regardless of type, it is essential to remember that all tanks eventually fail no matter how well it’s maintained. 

Why Tank Water Heaters Fail

A water heater may seem to fail out of nowhere, but that’s not the case. Water heaters fail over time. It is recommended you drain and flush your water heater annually as part of your home maintenance schedule. It would be best to replace your anode rod inside the water heater every 2-3 years. This sacrificial rod protects the lining inside the tank.

Water heater failure can often be predicted if you are aware of the signs. There are two main reasons why tank-style water heaters fail. These two reasons are:

Too much pressure inside the tank 

As the water heats up, it expands. This is expansion creates pressure inside the tank. If the water inside the tank heats up to the point that it exceeds the tank’s pressure specification, it could rupture. One of the ways to avoid this is keeping your hot water temperature under 140°F.

Modern water heaters are equipped with a safety feature called a temperature and pressure relief valve (T&P valve). The temperature and pressure relief valve open when the pressure inside the tank reaches the tank temperature threshold. This valve will expel hot water through a discharge pipe to the house’s exterior to relieve the pressure inside the tank.

Another safety feature that can be added is an expansion tank. Expansion tanks help control pressure inside the water heater tank by providing a place for hot water to expand. In a 50 gallon tank, hot water expands to 52 gallons. A 2-gallon expansion tank can store the expanded water. 

One of the problems with older water heaters is that they lack a T&P valve and an expansion tank to help control the water heater’s pressure. With nowhere to go, the pressure inside the tank can cause the water heater to explode, turning many older water heaters into a ticking time bomb.

Sediment Buildup Inside the Tank

The second leading cause of water heater failure is sediment buildup inside the tank. Chemicals and contaminants found in the water supply cause corrosion inside the tank, eventually rusting the tank, causing it to leak.

Once a flaw develops inside the tank, the tank’s pressure builds and forces water through these weak areas inside the tank. 

Water heaters with glass liners are equipped with an anode rod. The water heater anode rod attracts contaminants in water. Over time the contaminants will eat away at the anode rod rather than the tank.

The anode rod, in essence, sacrifices itself to protect the tank. Anode rods will last 3-5 years depending on the quality of the rod. 

Once the anode rod is eaten away, there is nothing left for settlement and contaminants to attack other than the tank itself. 

How to Maintain Your Water Heater

water heater

Drain and Flush Your Water Heater

As part of your annual maintenance on your water heater, you should drain the tank and flush out any sediment inside the tank. Tank water heaters have a drain valve at the base of the tank to do this.

Here’s a quick rundown of how you can drain and flush your water heater 

  1. Turn off the water supply before working on the water heater.
  2. Turn off power or gas to the water heater before starting work.
  3. Attach the hose to the drain valve and run it to the exterior to drain freely and safely. Remember the water will be hot.
  4. Open hot water tap at a nearby sink.
  5. Open the drain valve on the water heater to begin draining.
  6. Once the water heater has drained, turn the water supply back on the flush the tank.
  7. Close the drain valve once the water heater has been flushed and water running from the hose is clear.
  8. Allow the water heater tank to refill.
  9. Turn the power or gas back on to the water heater back. If you have a gas water heater, you’ll likely need to light the pilot.

Replace Your Anode Rod

The tanks inside most water heaters are made from steel. The steel tanks have a thin glass lining to protect the metal from corrosion. As the water heater ages, the glass develops cracks. Once the glass lining cracks, water starts to corrode the steel tank. This is where the anode rod steps in as a secondary line of defense.

The anode rod is a long metal rod inside the water heater that attracts corrosive elements in the water. Over time, typically 3-5 years, the anode rod will corrode to a point where it can no longer defend the water heater.

Once the anode rod has become so diminished that it can no longer do its job, the tank itself begins to rust. The good news is, if caught early, you can replace the anode rod and nearly double the lifespan of your water heater.

Anode rods are made from magnesium, aluminum, or aluminum/zinc alloy. Replacement anode rods can be purchased at local home improvement stores and are relatively easy to install.

It would help if you replaced your anode rod every 3 to 5 years. This can be done during your annual maintenance of draining and flushing the water heater. You may want to replace a low-quality anode rod with a better quality one that will last longer.

Signs You Need to Replace Your Water Heater

Age of the Water Heater

Age is a significant factor in your water heater’s performance. If your water heater is ten years old or older, you should expect to have higher maintenance costs or to replace it at any time.

If you’ve properly maintained your water heater, you may get up to 12-15 years of life from a gas water heater and 15-20 years from electric water heaters. Beyond that, replacement is recommended mainly due to rapid advances in safety and energy efficiency. 

Another factor with age, particularly with gas tank water heaters, is the water heater’s overall energy efficiency. Energy consumption is higher in older water heaters versus newer models, which will pay for itself over time. 

Rusty Water From Tank

If you see rusty or reddish-brown water from your water heater, that’s an indication that rust is mixing with water inside your tank. It’s a clear indication that your water heater needs replacement. 

If the water heater is not leaking, you may be able to buy some time by performing a drain and flush maintenance on the water heater to remove loose sediment and change your anode rod. However, depending on the condition of the tank’s interior, this service may not be sufficient.

Ultimately, if the tank is damaged or starting to leak, there is no other option but replacement.

 Gurgling Sounds Inside Your Water Heater

As your water heater gets older, sediment begins to build up at the bottom of the tank. When the sediment is heated and reheated over time, it begins to harden.

Suppose you hear banging, crackling or gurgling sounds from inside your water heater that indicates a sediment buildup inside the tank. It is recommended that you try to flush and drain your water heater. This maintenance may prolong the water heaters’ life if caught early. 

Depending on the amount of sediment build-up inside the water heater, the drain valve may be clogged or blocked, preventing it from draining water properly. One option would be to try replacing the drain valve to clear sediment from the water heater. 

If all attempts to drain and remove the sediment fails, then replacement is the best option. In this case, the water heater’s replacement is recommended before a catastrophic leak occurs, which could cost thousands of dollars of damage to your house. 

Leaking from the Bottom of a Water Heater Tank

water heater

If your water heater is leaking, that is a good indication that there is something wrong. See our How to Repair a Leaking Water Heater – Complete Step by Step Guide for steps to repair a leaking water heater. You need to contact a licensed plumber to have them examine your water heater for repair or replacement. 

Some leaks can be repaired while others can not. Leaks located around the top of the water heater, such as around the supply pipe fittings or the T&P valve, is likely repairable. However, this is not always the case and is still an indication that something is going wrong internally that needs to be addressed.

If you’ve noticed water on the floor around your water heater, then you could have a severe problem. Internal leaks in tanks can’t be repaired. If water is leaking from the bottom of your tank, you should plan on an immediate replacement and call a licensed plumber.

The Water Heater Stops Producing Hot Water

Hot water is a daily luxury we’ve all become accustomed to. No hot water can be an inconvenience. If your water heater is not producing hot water, there are a couple of things that could be the cause. One is there is likely a problem with the heating element or the electric thermostat.

Another possibility is a broken drip tube. The drip tube is a plastic pipe that runs from the cold water inlet to the tank’s bottom. If this pipe is broken, cold water and hot water mix resulting in lukewarm water from the tank.

These items do commonly fail over time and can be repaired by a licensed plumber. These items are relatively easy to replace for the handy do it yourself person. 

Cost to Repair a Tank Water Heater

If caught in time, most water heater repairs are relatively inexpensive and easy to do. However, this may not always be the best option. Here are some things that you should consider:

  1. How much will the repair cost? One of the things you should consider is the repair cost and whether you can do that repair yourself or if you need to hire a licensed plumber. If the water heater is experiencing a higher maintenance level, a replacement water heater will be your best option. 
  2. What is the life expectancy of the water heater? There’s no point in throwing good money after bad. If your repair cost will be as much as half the cost of a new water heater and will only provide a small amount of remaining life expectancy, then replacement would be your best option. 
  3. What is the cost of a new water heater? The last thing to consider is how much it will cost to have a new water heater installed by a licensed plumber. 

Cost to Replace a Tank Water Heater

Now that you’ve determined it’s time to replace your water heater, there are some things you need to consider:

  1. Will you be replacing the water heater with a similarly sized unit? When you decided that it’s time to replace your water heater, it may be an excellent time to make an upgrade or to switch to a tankless system. Some of the factors that go into this decision will depend on your situation. If your house is damaged by a leak or needs to move the water heater to a new location, replacement is recommended.
  2. Do you need a larger tank to meet your family’s needs? If your family has grown since the water heater was installed last time, a larger water heater may be desired. However, there are limitations to size when choosing water heaters, depending on where you live.
  3. Will you install the water heater yourself or hire a licensed plumber? It is always recommended that you hire a licensed plumber to install a new water heater. Licensed plumbers in your area will know local building codes that you may not be aware of. However, depending on your skill level, you may be able to install your new water heater yourself. 

Be Aware of Hidden Costs

We touched on building codes and number three in the previous section. When you replace a water heater, you will be required to meet all current building codes. 

There may be costs greater than just the water heater itself. Some of the hidden costs you may see when installing a new water heater include:

  1. Expansion tanks expansion tanks are used to help control pressure inside and water heater. 
  2. Seismic strapping – depending on where you live, seismic strapping may be needed if you live in an area prone to earthquakes.
  3. Drain pans – drain pans are placed under the water heater to catch leaks and discharge water to the exterior to protect the structure of your home. 
  4. Plumbing pipe upgrades – Depending on the type of plumbing supply pipes you have in your house, upgrades may be needed. For example, if your home has polybutylene piping, you will likely need to replace all accessible piping during installation.

New Water Heater Tank and Installation Costs

According to HomeDepot.com, the average cost of a new water heater installation is approximately $1,308. Nationwide costs typically range from $952 to $2,098. This replacement estimate includes the following components: 

  • Traditional tank water heater – typical water heater size is 40 or 50 gallons.
  • Permits to install new water (some locations do not require this).
  • Installation materials such as fittings, shut off valves, piping, etc.
  • Installation labor by a local, licensed, and insured plumber.
  • Removal of the old unit following local laws.

If you choose to purchase and install a water heater yourself, you can expect to pay between $350 to $2000 depending on the size and type of water heater you decide to purchase.

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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