How Much Does It Cost to Add a Water Heater Expansion Tank?

Your water heater is the unsung hero of your plumbing system, providing a steady supply of warm water for baths and showers. However, this essential fixture also produces something not so great for your home — pressure. Allow thermal pressure to build up, and you could find yourself facing a plumbing nightmare.

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A water heater expansion tank prevents burst pipes by providing an outlet for thermal pressure. Below, we'll tell you everything you need to know about this nifty device and explore how much a water heater expansion tank costs.

What Is a Water Heater Expansion Tank and What Does It Do?

A water heater expansion tank is a small tank attached to a supply pipe in your plumbing system. It relieves pressure in your hot water system and prevents water pressure and temperature fluctuations.

Traditional tank water heaters store hot water to supply the fixtures in your home. Water expands as it heats, increasing the pressure on your tank and pipes and potentially causing the tank to overflow. A water heater expansion tank solves this problem by allowing any overflowing water to flow inside. Without an expansion tank, the thermal pressure continues to build, increasing the risk of your pipes or hot water tank bursting.

Water heater expansion tanks are much smaller than your main water heater tank, usually holding between 2 and 5 gallons. Generally, larger water heaters require larger expansion tanks. The water pressure can also impact the size of the expansion tank you need, and a qualified plumber can help you select the most suitable option for your needs.

Is an Expansion Tank Necessary For a Water Heater?

Whether you need a thermal expansion tank depends on your water heater's make, model and age. Older tank systems are more likely to require expansion tanks. Leaky faucets, inconsistent water pressure and strange noises coming from your plumbing often signify water pressure issues, and installing a water heater expansion tank may help solve the problem.

You won't need an expansion tank if you have a tankless water heater. That's because these devices heat water on demand and don't store large quantities of hot water in a tank. A certified plumber can inspect your system and help you determine whether you need a water heater expansion tank.

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How Much Does a Water Heater Expansion Tank Cost?

How much a water heater expansion tank costs depends on several factors, including the size of your water heater and the pressure in your plumbing system. According to Forbes, the average cost of expansion tank installation is $220 (CAD 270) for materials and labor, with most homeowners spending between $90 and $350 (CAD 122 and CAD 473).

Expect to spend between $40 and $200 (CAD 54 and CAD 270) for the tank itself, excluding the cost of labor. Most plumbers charge between $50 and $150 (CAD 68 and CAD 203) extra to install a water heater expansion tank. Your plumber may charge more than average if you need to install your tank in an inaccessible area or live in a city with high labor costs.

Labor charges significantly impact the overall installation cost, so it's hardly surprising that some homeowners consider installing water heater expansion tanks themselves to save money. However, installing an expansion tank is relatively complex and often requires cutting into your existing pipes.

Without an extensive understanding of plumbing techniques and local building codes, you could compromise your entire water supply and violate safety regulations. In other words, you should leave expansion tank installation to the professionals unless you have expert-level knowledge.

What's the Life Expectancy of a Water Heater Expansion Tank?

How often you need to replace an expansion tank depends on several factors, including the quality of your unit, how frequently you use your plumbing system and the mineral levels in your local water supply. As a rule of thumb, the expected lifespan of a thermal expansion tank is around five to 10 years. Consider an expansion tank replacement if you notice water pressure fluctuations, mineral deposits or dripping fixtures.

All CAD conversions are based on the exchange rate on the date of publication.