How to Keep Your Water Heater from Exploding

Written by William Kirkorian of Your 1 Plumber
Updated November 22, 2012
water heater valves
A plumber can do a water heater safety inspection to make sure each valve is working properly. (Photo by Brandon Smith)

To prevent pressure buildup in your water heater, the T&P valve and thermal expansion tank are crucial … as is regular maintenance.

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If you search the Internet, you’ll find conflicting stories about whether water heaters really do explode. As with any debatable plumbing topic, there are opinions at both extremes.

“Impossible!” say the naysayers.

“Duck!” say the alarmists.

Well, at Your 1 Plumber we say this: However rare the occurrence, water heaters can explode. 

Your water heater is under pressure

Water heaters have many important components, but none is more critical than the temperature relief valve.

To ensure their safe operation, water heaters must be installed with temperature and pressure relief valves. A T&P relief valve is a two-in-one safety device, which, as its name implies, responds to both excessive temperature and to excessive pressure in a water heater.

When the temperature gets too hot, the thermostat expands. When that happens, the disk inside the thermostat is lifted off its seat to discharge the overheated water. Then cooler water enters the tank to moderate the water temperature.

Playing it safe with your water heater

Your water heater’s temperature relief valve also responds to excessive pressure by discharging water to prevent a further increase of pressure. If a T&P valve is dripping, it’s usually a sign of thermal expansion, which can prevent the valve from closing tightly.

 When water is heated in a closed system, it expands and causes an increase in pressure. When the system is opened, pressure will return to normal, and the relief valve should stop dripping.

In Maryland, all water heaters must have an attached thermal expansion tank to help keep system pressures from reaching critical limits.

Regular maintenance prevents water heater explosions

At Your 1 Plumber, there are two primary services we offer that help ensure the safe operation of your water heater.

•  First, we conduct comprehensive water heater tune-ups and safety inspections. In the process, we make sure that your T&P valve and thermal expansion tank are both working properly.

•  At the same time, we check for possible gas and carbon monoxide leaks. Next, for natural gas water heaters, we can install an automatic gas shut-off valve that stops the flow of gas if the ground moves or if gas flow increases dramatically.

Jump in the tub, the water heater’s fine

As you can see, a well-maintained water heater has systems installed that prevent pressure from building up and causing an explosion.

So with proper and regular maintenance, you and your family can check “exploding water heater” off your list of things to worry about.

About this Experts Contributor: A family owned and operated residential plumbing company in Germantown, Maryland, Your 1 Plumber is a customer-focused company that has been serving homeowners in Montgomery, Prince George, Howard and Fredrick counties for more than 15 years.

As of November 21, 2012, this service provider was highly rated on Angie's List. Ratings are subject to change based on consumer feedback, so check Angie's List for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angie's List.

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