Flushing a water heater is by far one of the most important maintenance tasks as it helps to prevent most common problems and can also extend the life of your unit. Traditional tank water heaters need flushed to remove all of the sediment that collects inside the tank, which forms naturally due to the dissolved minerals in your water. Sediment isn’t a problem with tankless water heaters since they don’t store hot water. However, these units still need to be flushed and cleaned regularly to prevent issues caused by limescale. Today, we’re going to look at the reasons why flushing a water heater is so essential as well as how often you should have your unit flushed and how it is done.

How Often Should a Water Heater Be Flushed?

The general recommendation is that all water heaters should be flushed at least once a year, and this is the case no matter whether you have a tank water heater or a tankless unit. That being said, the fact that most of Michigan has extremely hard water means that both sediment build-up and limescale will be much bigger problems than in areas with soft water. As a result, you may want to have your unit flushed every six months or so if your plumbing system doesn’t have a water softener.

What Happens If You Don’t Flush Your Water Heater Regularly

The purpose of flushing a tankless water heater is to clean out any limescale build-up inside the unit. If these units aren’t flushed regularly, the limescale can begin to clog the pipes and limit how much hot water the unit can produce. Limescale can also prevent the unit from heating properly, which means your water may start to never get as hot as you want or need.

Flushing a tank-style water heater is even more important as sediment is the primary cause of many different issues, and the specific issues it can cause depends on whether you have a gas or electric unit. With electric tank water heaters, the main issue is that sediment can damage the unit’s lower heating element or cause it to fail completely. In either case, the unit will take far longer to reheat and your water may never get hot enough even if the upper heating element is still working properly.

Sediment build-up is an even bigger issue for gas water heaters and can lead to the unit making loud noises and not heating properly or taking far longer to reheat. If you’ve ever heard your water heater make a loud banging sound when it’s running, this is often caused by sediment. Whenever the unit heats, small bubbles of hot air are produced. These bubbles normally rise up to the top of the tank without issue. However, if there is a lot of sediment, these bubbles will disturb the sediment and cause it to knock against the insides of the tank.

Although some heat is absorbed through the unit’s exhaust flue that runs through the middle of the tank, most of the heat comes directly from the gas burner underneath the tank. The issue is that sediment will insulate the bottom of the tank and absorb much of the heat from the burner. This means that the water will heat far more slowly and the unit will use more energy and have a much longer recovery time once all the stored hot water has been used. This is one of the reasons that sediment will decrease the life of your unit as the more it runs, the shorter it will usually last.

As the sediment absorbs heat, it also often leads to hot spots forming that can start to weaken the tank and speed up the rate at which it corrodes. Over time, this can lead to the tank beginning to leak. You may be lucky and your tank will only have a minor leak, but there is also the chance it could fail completely and send its entire contents flooding out into your home.

How to Flush a Water Heater and Why It’s Always Best to Have a Professional Do It

The process for flushing a water heater is mostly the same for tank and tankless units. The main differences are that a tankless unit obviously doesn’t need to be drained first, but will need to be cleaned and descaled. In either case, the process basically involves hooking up a hose to the unit and then running water through it to flush it out.

Flushing a tankless water heater is normally something you could do on your own. Nonetheless, we would always recommend having a professional do it for you as part of your routine maintenance to ensure it is done correctly.

Flushing a tank water heater is slightly more difficult and is always best left to the professionals for a number of reasons. The first is that there is a risk you could get scalded if you don’t turn the unit off and let the water in its tank cool before you drain the unit. Another reason is that the sediment will often continually clog the unit’s drain valve as it is being flushed. In some cases, the only way to clear the clog is to backflush the unit by connecting it to another water source, and this is typically not something you’ll want to try on your own. There are also times when the only way to clear the clog is to remove and replace the drain valve, and this can lead to a major flood if not done properly since the tank will still contain lots of water.

After making sure that the water in the tank is sufficiently cooled, a plumber will first shut off the water supply to the unit and then connect a hose to the drain valve so that the tank can be drained. In order for the tank to drain properly, at least one hot water fixture must be open as otherwise a vacuum will form inside the tank and prevent the water from draining out.

Once the tank is mostly drained, the plumber will then turn the water back on to start flushing out the sediment. Depending on the level of sediment, this could take only a few minutes or up to an hour, and it is necessary to continue flushing the unit until no more sediment comes out and the water that drains from the unit is completely clear. Once the process is finished, they will then close the drain valve, disconnect the hose and turn the unit back on so it can start to reheat. Depending on the age and effectiveness of the unit, you will usually need to wait somewhere between 30 minutes and two hours before your water will again be fully hot.

If you need to have your water heater flushed, repaired, or maintained, Bel-Aire Heating & Cooling is ready to help. We service all types of water heaters from most any brand, and we can also help if you need a new unit installed. In addition, we offer a full range of cooling and heating services for customers in Grand Rapids, Portage, Three Rivers and throughout Western Michigan. For more information or to schedule any water heater or HVAC service, give us a call today.

company icon