In The News … Why an Expansion Tank Is the Best Home Investment You Can Make

Most people don’t think about their hot water heaters until something goes wrong, why would you! The danger is once something “goes wrong” you could be looking at something as simple as no hot water in the shower or as life threatening as a carbon monoxide leak. Luckily there is a simple fix you can make that will eliminate most serious problems.

Expansion tanks are used to prevent water leaks from your hot water heater. When your hot water heater turns on, the water within the piping system begins to expand. Without the expansion tank, the expanding water can create too much pressure on the heater and potentially fail. If you have an expansion tank the expanding water enters the expansion tank.

The expansion tank contains compressed air and a rubber “bladder” that holds the water until needed. Eventually, the hot water is drawn from the system thru a faucet and the expansion tank releases the extra water into the piping system to be used by you.

Fairfax County recently passed a new  county code requiring that all hot water heaters have an expansion tank installed if any maintenance is done to the water heater.

What does this mean for you? If your hot water heater needs maintenance for any reason, the contractor sent out will be required to note that there is no expansion tank and will be required to install one if any work is done to the hot water heater. Depending on the size of your water heater, this installation (parts and labor together) typically runs between $150-$250.

In Loudoun, Arlington and Alexandria counties the expansion tank is only required if the whole system is being replaced. Most water heater specialists will recommend you install the tank but it is not required.

It may seem like a hassle to worry about but the expansion tank has some great money saving benefits you may not even realize. Not only are you preventing future leaks with this investment, you’ll also see a reduction in your water bill each month! The extra water that you don’t use is no longer pushed back into the water main supply, instead it is held in the tank for your later use!

Investing in a expansion tank could be one of the easiest, cheapest, “bang for your buck” home improvement fixes you can make. While your home is tenant occupied it is important to consider their safety as well as yours when you return. For a very low price you could potentially be saving your family from a disaster. For more information please contact our Repairs Department at


  1. says

    Get a thermometer.You cant rely on feel as you are camporing the tank to the air in the room. If the room is 25C and the water is 25C, the water actually feels cool. But if the air is 15C, and the tank is 25C then the water feels warm.Measure the temp in the tank, and adjust the heater as needed. In the summer the heater may hardly switch on at all, but in winter you are going to need it.The numbers on the heater are only approximate, especially on the cheaper heaters. Measure the actual temp after 24 hours, and wind the heater up and down a few clicks to get it right.IanEdit trust the thermometer, not your hand. As it’s summer in your part of the world, then room temp is probably about right for the tank. In winter the tank will feel warm.

  2. Tu Ha says

    From what I’ve read, these expansion tanks have a rubber bladder that expands and contracts to handle the rise and fall of water pressure. Has anyone done any long term studies to see what the health effects are of hot watter sitting in a rubber bladder? The reason I ask is because we’ve been noticing a lot of black sediments in our dishwasher, launder machine, bath tub. Even after draining the water heater twice, the black sediment still comes out. The culprit seems to be the rubber in the expansion tank corroding over the years. This is dangerous if ingested, since many people use hot water for cooking. Could you please refer me to the county code(s) that require this? I’m looking to see if there’s any way around this.

  3. Rad says

    You don’t have to have the expansion tank on the hot water line rather on the cold water in line. The function is the same and you don’t have to worry about the hot water damaging the rubber in the expansion tank.

  4. says

    This is an awesome post. I’m so glad you are helping educate people about expansion tanks. We install them on every water heater we put in here in Kansas City.

    The Bradford White water heaters we install are lined with glass on the inside of the tank which holds up very well against corrosion from hard water. However if you don’t protect against thermal expansion the glass will crack and your water heater will leak. Most of the time the expansion tank will fail before the water heater, so you should check the pressure every year especially with an older water heater.


  1. […] @huzilla you got me wondering as to why I need it….here is an article that talks about them Why an Expansion Tank Is the Best Home Investment You Can Make Expansion tanks are used to prevent water leaks from your hot water heater. When your hot […]

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