Ask Pete: How Do I Flush A Water Heater?

When you become a homeowner, you have a lot of responsibilities, and one of them is managing household appliances, like the water heater. Today, we’re going to ask Pete a few questions about maintaining a water heater, and specifically how to flush a water heater. 

When you bought your water heater, you were likely advised to flush it annually. So, what does that mean? Let’s ask Pete!

Q: Pete, How And Why Do You Flush A Water Heater?

A: I’ll get to the how in a second but the why is really quick and easy to answer, so I’ll start there. All water coming into your house has additives and natural sediment and minerals that can form deposits that will eventually gunk up your systems, and can even cause failures. Arizona has some pretty hard water so those naturally occurring elements build up in your system and can cause significant damage if you don’t clear it out once or twice a year. 

The “how” is just a few steps for a pro and we can do it in about a half hour. A do-it-yourselfer is going to take a bit longer the first couple of times till you get the hang of it and have all the right equipment. There are different requirements for tankless water heaters, by the way. I want to stress that I’m giving you an outline for a typical tank water heater here, to actually do it, you need a lot more information specific to your unit:

  1. Turn off the cold water intake and the gas or electric unit
  2. Make sure the unit is off
  3. Wait an hour or two for the water inside the tank to cool
  4. Attach a hose to the drain valve on the unit and put the other end of the house into a bucket or into a drain (if you have one close by)
  5. Turn on at least one faucet in the house so that a vacuum doesn’t form in your pipes
  6. Turn the drain valve so the water can release into your drain hose and most of the sediment will drain out with the water

Then you will need to fill your tank back up, so shut off the drain valve, remove the hose, reset the cold water valve back and turn the unit back on. Keep the taps open until you see the flow is normal and then wait about a half hour to test for hot water at the tap. I want to mention that a tankless water heater is a bit more of a complex job and we usually use pumps in the bucket when we work on those, so check your manual because it is a different process.

Q: Can You Flush My Hot Water Heater Yourself?

A: Yeah, sure. If you consider yourself to be handy, then it is something you can tackle. We just recommend that you read your particular water heater’s manual and follow a high quality tutorial so that you don’t accidentally cost yourself a whole lot of trouble and money.

Q: How Do I Know If My Water Heater Needs To Be Flushed? 

When it’s time! It does need to be done every two years minimum and better still to do it annually, but if you notice things like, 

  • A smell or visible sediment in your water 
  • That your water isn’t flowing as fast as it used to
  • That your water isn’t staying hot as long, or fails to get hot (just stays warm) 
  • Is making strange sounds
  • Higher electric or gas bill

Then you may need to flush your water heater. And, not to scare you, but it is serious. There is a pressure relief valve, and that basically keeps your water heater from exploding, and if it gets corroded or affected by too much sediment, that could be a very big problem. Nobody wants that, so be sure to get your system flushed according to your unit’s manual. 


Thanks, Pete! Helpful as always. 

So, now that you know what a water heater flush is, and how to do it, you may decide like most of us that you would rather have a professional do it for you in a quick half hour service. If you are in the Mesa/Gilbert area, give us a call to get a free estimate for water heater flush service by calling 480-388-6093.