range of tankless water heaters

How Long Do Water Heaters Last? Everything You Should Know

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When it comes to home maintenance, few appliances are as essential as the water heater. Understanding the lifespan of your system is a key part of home management and can save you from costly water heater repairs or premature replacements. 

In this comprehensive guide, we explore the factors that determine your water heater lifespan, the signs that indicate the end could be near, and how to choose the right installer and system to suit your needs. 

What Determines the Lifespan of a Water Heater?

Several factors influence the lifespan of a water heater, including the type of water heater, the fuel source it uses, how it's maintained and even the quality of its water supply. In answering the question, "How long do water heaters last?" it's typically between 8 and 20 years but can vary significantly based on these factors. 

Type of Heater

The type of water heater you have can influence water heater life expectancy. Some models, for example, are more susceptible to corrosion or sediment buildup. These vulnerabilities may not be obvious or explained to you at the time of purchase. Therefore, it's important to understand the type of water heater you have so you can estimate its lifespan and plan for its future replacement. 

electric tankless water heater

Traditional Tank

Traditional tank water heaters are the most common type of hot water heater. These systems store and heat water in a large separate tank. The water is heated at least once a day to ensure a steady and ready supply of hot water. On average, these water heaters last between 8 to 12 years. They're often affected by sediment buildup. Annual flushing of the tank can help to extend a tanked water heater's lifespan. 

gas tankless water heater


Tankless water heaters, also known as on-demand water heaters, heat water directly without the use of a storage tank. They're growing more and more popular among homeowners as they boast excellent energy efficiency and have an average lifespan of around 20 years. 

Because they have no storage tank, there's no sediment or corrosion to affect their longevity. Additionally, because tankless heaters heat water on demand, they're less likely to experience the wear and tear associated with constant heating and reheating. 

Fuel Source

The type of water heater you have can influence water heater life expectancy. Some models, for example, are more susceptible to corrosion or sediment buildup. These vulnerabilities may not be obvious or explained to you at the time of purchase. Therefore, it's important to understand the type of water heater you have so you can estimate its lifespan and plan for its future replacement. 

electric tankless water heater


Electric water heaters are popular for their simplicity and safety. They generally last between 10 to 15 years. Regular electrical checks and element replacements can help maximize their lifespan.

gas tankless water heater


Gas water heaters are often preferred for their quick heating ability. They tend to last about 8 to 12 years. Annual inspections and maintenance visits are crucial for safety and efficiency, especially for the burner and venting system.

Why Do Water Heaters Fail?

There are several reasons why water heaters fail, requiring repair or replacement. Early intervention and regular maintenance can often extend water heater lifespan. 

Common Causes of Failure (All Types)

Hard Water Deposits and Obstructions

Minerals can build up in your water heater, especially if you have hard water. These deposits can potentially clog pipes and reduce efficiency. While the problem can often be resolved with cleaning and descaling, severe cases could require the replacement of components or a system overhaul.

T&P Valve Failure

The temperature and pressure (T&P) relief valve is a critical safety feature that releases pressure if it gets too high inside the tank. Over time, this valve can suffer wear and tear and eventually fail completely. 


Rust and corrosion can wreak havoc inside your water heater, leading to system damage and leaks. Once corrosion sets in, it can be difficult to fix. While patching up rusted areas can provide a temporary solution, a replacement will usually be required down the line.

Anode Rod Failure

Often known as a "sacrificial" rod, the anode rod is designed to protect the metal tank from corrosion. It does this by attracting corrosive elements in the water, causing the rod to corrode instead of the tank. Over time (around 3 to 5 years), the anode rod will wear out and require replacement. 

Water Pressure Is Too High

Excessive pressure can put a lot of stress on your water heater, leading to failure and premature replacement. The installation of a pressure-reducing valve or an expansion tank can solve this problem. 

System Is Overloaded or Overworked

Your water heater is in high demand throughout the day. Continuous overuse can put strain on your system, leading to premature failure. This often calls for a system upgrade or replacement with a water heater that better suits the needs of your household. 

Loose Pipe Fittings

Loose pipe fittings can cause leaks, leading to water damage. If caught early, these issues can often be rectified. However, ongoing problems can cause extensive damage, requiring more extensive repairs or system replacement. 

Old Age

Despite regular maintenance and timely repairs throughout its lifetime, there will be a time when your water heater naturally wears out. 

Faulty Thermostat

A problem with your thermostat can result in inconsistent water temperatures or complete loss of control of your water heater. A new thermostat will usually solve the issue.

Tank Water Heater Failures

Storage Tank Is Rusted or Damaged

One of the most common causes of premature failure of a tank water heater is rust. Corrosion is a silent killer, occurring from the inside due to constant contact with water and sediment. As the rust takes hold, it causes weak spots on the inside of your tank, leading to leaks and water damage. 

Tankless Water Heater Failures

Heat Exchanger Leaks

While tankless water heaters don't have a tank, they can still be vulnerable to leaks. A common cause of leaks in tankless models is a faulty heat exchanger. These parts can be complex to repair, and replacement is often an easier and more economical solution. 

Electric Water Heater Failures

Faulty Electrical Connections

Electric water heaters depend on reliable power connections to operate correctly. A faulty connection can lead to a number of problems, including intermittent hot water, no hot water or potential safety concerns. 

Gas Water Heater Failures

Ignition System Failure

If you've just woken up to no hot water, it could be the ignition system that's at fault. This system is responsible for lighting the gas burner that heats your water. The problem could be down to a malfunctioning pilot light, a faulty igniter or an issue with the control valve. 

Improper Exhaust Ventilation

Proper exhaust ventilation is crucial for the safe operation of your gas water heater. It's essential that toxic gasses, such as carbon monoxide, are expelled efficiently. A problem with exhaust ventilation can lead to dangerous conditions and requires immediate attention.

Gas Leaks

Water heater gas leaks can pose a serious safety hazard and need immediate attention. These leaks can occur due to faulty valves, corroded or loose connections, or a worn gas line.

Signs Your Water Heater Is Nearing the End of Its Lifespan

Electric water heaters, tank and tankless

Check the Serial Number (Age)

Your water heater's age is your first indication of its remaining lifespan. Most heaters have a lifespan of 8-20 years. The serial number (usually found on a sticker on your unit or in your manual) often includes the date of manufacture.

Visible Rust or Damage

Rust, either on the tank exterior or in the water itself, suggests internal corrosion, a sign the tank may soon start leaking. External damage could also be indicative of potential internal issues.

Inconsistent Water Temperature

Fluctuations in water temperature or a consistent failure to reach the desired heat level can indicate element or thermostat failure in electric heaters or burner issues in gas heaters.

Discoloration or Deposits in Water

Murky, discolored water or visible sediment can suggest rusting inside the tank or a buildup of minerals, indicating the unit is deteriorating internally.

turning the cold water off

Water Smells or Tastes Bad

Unpleasant odors or tastes in the hot water can be a sign of bacterial growth inside the tank, often due to sediment buildup providing a breeding ground for bacteria.

Loud Noises

Banging, rumbling or popping noises can be caused by the buildup of sediment at the bottom of the tank, indicating that the water heater is working harder than normal and may be close to failing.

Water Leaks

Any signs of leaking around the water heater, whether from the tank itself, the fittings or pipes nearby, can indicate the tank is failing or connections are loose or corroded.

Why You Should Replace Your Water Heater Before It's Too Late

gas tank water heaters

Protect Your Home From Water Damage

An old or malfunctioning water heater poses a risk of leaking or bursting, which can cause significant water damage to your home. By replacing it before it fails, you can prevent costly damage to floors, walls and personal property.

Avoid the Stress and Cost of Emergency Repair or Replacement

Emergency repairs or replacements can be stressful and often more expensive. 

A planned replacement with an authorized service provider will ensure you choose the right water heater for your needs. 

Take Advantage of Energy Savings & Improved Performance

New water heaters are generally more energy-efficient and perform better. Upgrading your unit can lead to savings on your energy bills and provide a more consistent supply of hot water.

Extending Your Water Heater’s Lifespan

handling equipment

Flush the Tank at Least Once a Year

Flushing the tank helps remove sediment that builds up over time, which can cause corrosion and reduce heating efficiency. Regular flushing prolongs the life of the heater and maintains its performance.

Regularly Inspect Key Components and Replace Them if Necessary

Regular inspections can identify wear before it leads to bigger problems. Knowing what to look for and when to repair or replace components is key to extending the life of your water heater.

Pressure Relief Valve

This valve releases pressure from the tank to prevent it from getting too high. Regular checks will ensure it is functioning correctly. 

Anode Rod (Replace if Badly Corroded)

The anode rod is designed to corrode over time to protect the tank from rust. Proactive checking and replacement can significantly extend the life of your water heater.

turning the cold water off

Tank (Check for any Cracks, Leaks and Rust)

Regularly inspect the tank for signs of cracks, leaks or rust. Early detection of these issues can prevent more severe problems, like major leaks or water damage. If you notice any of these signs, it may be time to repair or replace the tank.

Pilot Light/Ignition System (Gas)

For gas water heaters, ensure that the pilot light or ignition system is functioning correctly. A malfunctioning pilot light or ignition can lead to inefficiency or a complete shutdown of the heater. Regular checks can prevent these issues.

Water and Gas Lines

Inspect the water and gas lines connected to the heater for any signs of leakage, corrosion or damage. Maintaining these lines in good condition is essential for the safe and efficient operation of the heater.

Install a Thermal Expansion Tank

Installing a thermal expansion tank can help manage the pressure caused by thermal expansion in a closed water system. This can prevent excessive pressure on your water heater, extending its life and preventing potential damage.

Insulate the Tank and Pipes to Prevent Condensation

Insulating the water heater tank and pipes helps maintain the water temperature, reduces energy costs and prevents condensation, which can lead to rust and corrosion. This simple measure can significantly improve efficiency and prolong the life of the heater.

Improve Your Water Quality With a Softener or Filtration System

Hard water can lead to faster sediment buildup and corrosion in your water heater. Using a water softener or filtration system can improve water quality, reducing these risks and extending the life of your water heater.

Opt for an Extended Warranty from the Manufacturer

Selecting the right water heater is the first step in the replacement process. You might also want to consider an extended warranty. This can provide peace of mind and potentially cover the cost of repairs or replacement parts, ensuring the longevity of your water heater.