Basic Water Heater Maintenance – Draining the tank

It’s ok, you can admit it and in fact, I will start – I have not drained my water heater in a few years. Fortunately, for me the water is not that “hard” where I am. “Hard” water is simply sand, minerals, and other solids found in water. Now, if I still happened to live in Phoenix, I would be running into some serious issues. While small amounts of sediment that settle to the bottom the tank are not that big of an issue, over time they can start building up. In both gas & electric water heaters this can result in a loss of available water, can block the transfer of heat to the water and potentially clog the drain line making it almost impossible to drain.

Step 1: The most important step, that is most often overlooked (Orange)

Electric Water Heater (Left Side): Turn the power off to your electric water heater & tape the breaker in the off position. In some cases, your builder, electrician or plumber may have been nice to you & installed an actual outlet, so you can simply unplug it. If you forget to shut off the power & expose the heating element(s) you will more than likely burn them out.

Gas Water Heater (Right Side): There are two trains off thought here, some simply say that you need to turn the gas off, while others simply say that turning it to pilot is more than adequate. In my house, I have no problems with just turning it to the pilot setting, while in a customer’s house I will turn the gas off not only at the thermostat but also at the supply.

Step 2: Turn off the cold water supply to the tank.

Step 3: Attach a garden hose to the drain valve at the bottom of the tank. (Red)

A few quick words on this – cheap hoses tend become very soft and are prone to leak when hot water is run though them. Make sure you run the house to a convenient drain, sump pump, etc… and not simply into your crawl space. In some cases where a drain is completely unavailable or happens to be higher than the water heater, you can always do the bucket brigade or buy a pump to help propel the water out and away from the house.

Step 4: Time to drain the water

First, open up a nearby hot water faucet, and then the drain valve on your water heater. After you have done this, you should open up the hot water side of any faucet. Open up the drain valve on the tank and allow it to empty. Depending on the size of the hose and pressure, you can expect it to deliver 9 to 17 GPM. So if you have a 50 gallon tank, the water should be flowing at full pressure for  3 to 6 minutes – if the flow is slow, is trickling, etc… turn on the cold water supply to the tank. Turning on the cold water supply should hopefully help you blast through the clog.

Step 5: Rinse and Repeat

When the tank is finally empty, go ahead and shut off the drain valve.  Turn the cold water supply back on & let the water heater start to refill. This will help loosen up some more sediment in the tank. Once the tank is partially filled, (about 1/2 to 2/3 full) let the tank fill partially and start the draining process again. Once the water starts flowing out, go ahead and turn the water supply off. If you have extreme amounts of sediment still in the tank, you may have to repeat this procedure a few more times.  Look at the drain water… if it is running clear, you are done.

Step 6: The final few steps

Time to reverse the steps, well for the most part… First, you need to shut off the drain valve & unhook the hose. Open the cold water supply valve about halfway and allow the tank to slowly fill while checking for leaks. While this is going on, I suggest unscrewing the aerator on the open faucet & rinsing it off. Once the water starts to come out of the hot water faucet, the tank is full and you can turn off the faucet & re-install the aerator. Now, turn the cold water supply valve fully on, and then you can turn the electricity or gas back on to heat the water.

A few final notes:

Do you really need to clean out your tank yearly? It is a good idea, especially if you have well water or naturally hard water. If you are following our monthly maintenance checklists, we did list it as a yearly item simply because it is easier to remember than the ever popular, “Did I do it last year or not”?

Remember that with an electric water heater, you must turn the power off, because even a partial drain may expose the upper heating element to the air and permanently damage it! (Blue)

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As always, please stay safe; if you feel uncomfortable, do not understand how to complete a task, etc… please call in a professional. We at SLS Construction do not want to see or hear that you have been hurt or injured. We do offer Handyman Services for your convenience, and can even customize a maintenance contract for you to eliminate worry about many of these maintenance issues.