How Long Does a Water Heater Last? Signs to Look Out For

Much like the other systems in our homes, water heaters are incredibly important to our daily comfort. Whether it’s used for a hot shower after an intense workout or a quick way to get a head start on making a meal, hot water is needed for many things, especially during the winter months. 

So, in an effort to avoid having to face a lack of hot water on an incredibly cold winter day, many homeowners start to ask “how long does a water heater last?”.

There are many signs that you have a failing water heater, quite a few of which are also quite common and should be looked out for. We’ve included a few of those signs in this article to help you know when you should look into getting a replacement ahead of the system completely failing. 

If you’re interested in installing a new plumbing system after learning “when should you replace water heater units?”, just call our team at Diamondback Plumbing for help!

The Average Lifespan of a Water Heater

If you’re wondering, “how long does a water heater last?”, there are a number of factors that many plumbers and homeowners consider first. One thing of all these factors is what type the water heater is. As with most comparisons between the traditional tank type water heaters and tankless varieties, the average lifespan between them also varies. 

Tank water heaters often last between eight to twelve years depending on how well maintained and cared for the system is. Many tank systems feature an anode rod that attracts corrosive particles. 

However, as time goes on and the water heater ages, the rod itself corrodes, and the particles end up damaging the tank instead. There are often many signs that show when a tank water heater needs replacing, fortunately.

In contrast, tankless water heaters can last far longer than their tank-based counterparts, often working for twenty years or even longer. 

This is primarily due to how tankless systems work, though. Aptly named on-demand water heaters, tankless systems only draw in and heat water when a faucet needs it, effectively reducing the need to be constantly running. Much like their counterparts, tankless water heaters will eventually need replacing.

The Best Way to Check Its Lifespan 

Fortunately, there is one great way to know when to replace a hot water heater. Many water heaters have a serial code stamped somewhere on them. 

Depending on the letter and number – A to L for the month and number for the year – you can easily find out when the system was manufactured and determine whether you need to replace it soon.

When to Replace Your Water Heater in Your Home or Business

Knowing exactly when to replace a water heater can be difficult if you don’t know the signs. While using the water heater’s serial code can greatly help, there may still be the odd system or manufacturer that doesn’t have said code on it. In those cases, the next best option is by checking if you’ve noticed any of the signs that the heater is wearing down.

The Hot Water Is Oddly Colored

If you notice that the hot water is just the slightest bit red or yellow, you might need to replace your water heater soon. 

As mentioned before, rust can happen in both kinds of water heaters, especially since the tank system’s anode rod wears away. That rust that forms in an old water heater is more than likely going to mix with the water being moved to the taps. The result is a good answer to the question, “how long does a water heater last?”.

The Hot Water Smells Off

Another way to tell that your water heater is getting too old and needs a replacement is by considering what the water smells like. More often than not, rust is the main cause of damage in a water heater, and a small amount of rust – or iron oxide – isn’t harmful to the body. A faint metallic scent is okay but be sure to keep track of whether it gets worse. If it does, call a technician to replace the water heater.

Your Water Isn’t as Hot as It Was Before

Possibly the most easily noticeable answer to the question of “how long do hot water heaters last and when they need to be replaced?”, is the temperature of the hot water itself. 

Rust and other forms of damage can happen to more than just the inside of the tank and the water supply lines. In order to tell what temperature the water is currently and how much more heat it needs to reach a set level, there are often thermometers and other parts that read the temperature. Those parts can wear down too, leading to water that isn’t as hot as it should be.

Banging or Rumbling Noises

If you keep hearing odd banging or rumbling noises whenever you get close to the water heater, you might have already gotten one of the signs you need to replace it. Typically the banging is caused by hard water and the calcium in it. 

Over time, a lack of flushing in the system can cause the calcium to build, eventually hardening. This hard buildup can rattle around when the water heater turns on, creating bangs and rumbling while also damaging the system.


Water heaters are an essential part of a home and its residents’ daily comfort. Yet, it’s not very often that the homeowners consider its condition until an issue pops up or the hot water seems colder than it should be. 

Much like the other part of your home and even its appliances, your water heater does need a regular check. Doing so catches any small problems and allows you – or in most cases, a technician – to fix them before they worsen.

If you need a professional’s opinion on how to fix a water heater, how long it should last, or simply want to schedule a maintenance appointment, don’t hesitate to call Diamondback Plumbing today.

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