Can Water Heaters Actually Explode?

Explosion water heater

Can Water Heaters Actually Explode?


The short answer: Absolutely. For the long explanation: read on. Our Southern Arizona monsoons aren’t the only thing that can cause a ceiling to cave in or flooding to happen. There is another, much less expected suspect lurking in our homes…dun, dunn, dunnn (imagine dramatic sound effect here) It’s our water heaters! This disaster is one of the top five sources of residential water damage, according to the Insurance Institute for Business and Home Safety (IBHS), leading to an average of $4,444 per incident after the deductible was paid.


Sure, that’s scary. But the most important question is: will it happen to you?

Well, the answer is eventually deterioration happens to ALL water heaters, so it can happen to you if you don’t replace it soon enough. But, also, it’s likely to happen sooner due to these three preventable things.

1) Sediment build-up

The problem: Over time, sediment (minerals from your hard water) settle at the bottom of your water heater’s tank. This mineral layer insulates the water from the burner, forcing it to run longer to heat the water, causing it to overheat and deteriorate the tank.

You have this problem if: Your water heater makes a popping, knocking noise. That noise is water trapped under the sediment bubbling up, trying to escape the sediment layer. It’s like how boiling water pushes up a pot’s top.

How to prevent: You need to flush and drain the tank of the sediment once a year.


2) Rust corroding the tank

The problem: Your water heater is made of steel, which is mostly iron. Meaning that over time the water will cause the tank to rust.

Thankfully your water heater has an internal rust protection element: A “sacrificial” anode rod.

This 3-5 foot rod rusts in place of the tank (why it’s called a “sacrificial” anode rod). But once that rod deteriorates, your water heater rusting out will follow soon after.

You have this problem if: Your hot tap water is a brown, rusty color.

How to prevent: Inspect the anode rod once every two years and at least annually once the warranty has expired. You’ll probably change the anode rod once every 4-5 years—sooner still if you have a water softener.


3) Too much internal pressure

The problem: If you blow enough air into a balloon, what happens?  POP!

Same thing happens to water heaters. If too much pressure builds in the tank, it will eventually spring a leak and burst.

And if the pressure gets really ridiculous, the tank actually explodes, becoming part bomb, part rocket.

Thankfully, your water heater prevents this problem using its T&P (temperature and pressure) relief valve. It opens up, releasing some of the water to keep the pressure down

But even with the valve, all that extra pressure can wear down the tank over the years.

You have this problem if: Your water heater T&P valve keeps opening to release water. Also, if the T&P valve goes bad/starts leaking (which it will eventually), then pressure will continue to build in the tank, leading to a burst or explosion.

How to prevent: Pressure builds in the tank when you set the temperature too high (140-145 degrees).                                         


Make sure your water heater’s temperature is around 120-125 degrees. Any higher than that and not only will you increase the pressure in the tank, you increase the chances of getting scalded.

Also, test the T&P valve at least twice a year to make sure it can relieve your tank of pressure.

You can find the valve on the top or side of the tank. Just turn the switch up for 5 seconds and make sure it can release water (watch your feet, that water will be hot!).


When to Call?

If your water heater is showing any of these signs or it is simply past its prime, call Cal’s Plumbing today. Let one of our experienced technicians take a look at it for you. I promise you will get an honest opinion from a plumber who has only your best interest in mind. They will be able to tell you if there’s a problem that can be fixed or if getting a new one would be your best option.