Do You Need A Water Heater Expansion Tank?

Water heater expansion tanks can be very useful, so here’s our comprehensive overview detailing why you may need one!

water heater expansion tank in northern Utah home.

We’ve said it time and time again, but nobody tends to pay attention to their property’s water heater—until it’s too late. This is a huge mistake, especially considering just how vital water heaters are for our everyday comfort.

Water heaters tend to require regular inspections and maintenance on a yearly basis to ensure that they’re at full functionality, and our team of water heater repair experts is always here to support your home or commercial property’s water heater system.

We receive a lot of questions about water heater expansion tanks, so below we’ll be detailing the fundamentals of these special expansion tanks and why you may need one at your property!

What Exactly Is A Water Heater Expansion Tank?

Water heater expansion tanks are very small tanks that are installed on a water heater unit’s cold water supply line. The general purpose of this tank is to prevent thermal expansion, and protect water heating systems from its potential damages.

It’s important to remember that water expands as it’s heated up, which leads to an increase in molecular volume. This expansion can cause pressure buildups, which can then lead to leaks and other plumbing system issues. Expansion tanks provide a place for this expanded water to go, which reduces pressure and protects water heaters.

Expansion tanks are usually made of steel or other durable materials that can handle high amounts of pressure. As water expands, it enters the expansion tank—where air is compressed. Once you’re using hot water, the water will leave the expansion tank and be pushed back into your main water supply.

Many municipalities require water heater expansion tanks as a part of their plumbing codes for safety precautions that aim to protect water heaters and plumbing systems from potential thermal expansion damages.

Do Water Heaters Require An Expansion Tank?

There are several factors that come into play when it comes to expansion tank requirements, including the type of water heater, the size of the water heating system, and your local area’s plumbing regulations and codes. Most of the time, expansion tanks are required to prevent thermal expansion issues.

However, expansion tanks might not be necessary for your property if you have an open plumbing system. This includes gravity-fed and open-loop solar heating systems.

Your best option is always to consult with an experienced plumbing team in order to fully understand all of your municipality’s local plumbing codes, including expansion tank requirements.

Can I Do A DIY Expansion Tank Installation?

Although it technically is possible for a homeowner to install their own water heater expansion tank, it’s recommended to have a professional plumber conduct this type of installation project on your behalf.

This installation requires thorough water heater draining and many other intricate processes, so you shouldn’t do a DIY installation if you’re not fully comfortable with every step of the process.

What Causes Expansion Tank Failure?

Many northern Utah homeowners own a water heater expansion tank but don’t realize how these tanks can sometimes begin to fail over long periods of time. Some of the most common expansion tank failure causes include:


Expansion tanks can sometimes experience interior corrosion after many years of wear and tear, and this is typically due to the chemical reactions that occur within these tanks.


If your expansion tank becomes waterlogged, it might lose its overall ability to regulate water pressure. This can lead to a system failure.

High Pressure

When water pressure gets too high within an expansion tank, it can lead to a rupture or abrupt system failure.

Improper Installation

Expansion tanks are sometimes installed incorrectly, which is another common cause of failures.


Just like most mechanical components within your property’s plumbing system, your expansion tank technically has a limited lifespan and will eventually need to be replaced.

How Can I Tell When My Expansion Tank Is Failing?

The good news is that there are many telltale signs that can help homeowners recognize when their water heater expansion tank is beginning to fail. Some of these red flags include:


If water is leaking from your expansion tank, it’s a clear sign that it’s beginning to fail and will require a professional inspection.

Water Pressure Reductions

Any significant drops in your home’s water pressure are red flags that should be taken very seriously. Although low water pressure can be sourced back to many underlying problems, it could potentially be due to a faulty expansion tank.

Pipe Noises

If you’re hearing any knocking, clanking or banging noises coming from your pipes as you turn on your hot water supply, it could mean that your expansion tank is experiencing significant issues.


Any noticeable corrosion or rusting around your expansion tank is a serious cause for concern because it indicates that your tank is quickly deteriorating and in need of replacement.

Abnormal Energy Bill Increases

Faulty expansion tanks can often cause water heaters to work much harder than they’re actually supposed to, and this leads to abnormally high energy bills.

How Long Are Water Heater Expansion Tanks Supposed To Last?

There are many different factors that contribute to water heater expansion tank longevity, including the system’s water pressure, usage, and overall quality of the water heater unit.

On average, expansion tanks last around 5-10 years, but they can often last much longer when they’re properly inspected and maintained on a yearly basis.

Reach Out To Our Master Plumbers To Learn More About Expansion Tank Installations, Repairs & Inspections!

Beehive Plumbing is a top-rated plumbing business based in northern Utah, and our team of Master Plumbers has supported countless homes and businesses with our comprehensive water heater services over the past 20+ years.

We’re here for your property’s water heater, including your expansion tank’s installation, repair, and inspection needs. Contact us online or call us at 801-849-3839 to speak with our specialists today about what’s currently happening with your unit’s expansion tank!

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