To maintain the energy efficiency, safety, and useful life of your hot water heater, it is important that your home maintenance program include the proper care for your hot water heater.

Hot water heating is typically the third largest energy expense in a home, after space heating and cooling.  In addition, a water heater is a relatively expensive appliance, and it operates under very severe conditions (high temperatures, and cycling on and off).  Proper maintenance can significantly improve the energy efficiency, service life, and safety of this appliance.  See also: Furnace, Plumbing, Carbon Monoxide Detectors, and Basements.

Shown in the "Maintenance" tab above are the recommended routine maintenance tasks for your hot water heater. The "Questions / Answers" tab above shows our answers to related questions. And the "Articles" tab above provides links to related informational articles and sources.

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 Maintenance Task #1:  Flush out sediments and test pressure relief valve

 
FLUSH OUT SEDIMENTS:  On the side of the hot water heater, on the lower part of the tank, is a valve for draining water out of the tank of the hot water heater.  Draining water out of the tank flushes out sediments that settle to the bottom of the tank as the water is heated. 

To flush the tank:

1. For electrical water heaters, turn OFF the power at the circuit breaker.  And for gas models, turn the thermostat on the unit to the PILOT position.

2. Connect a garden hose to the drain valve at the bottom of the tank, and put the other end either in a 5-gallon bucket, a floor drain, or run the hose outside.

3. If you have a recirculation pump for your hot water system, then turn this off.

4. Shut off the supply valve for the cold water inlet to the water heater.

5. Open a HOT water faucet in a sink closest to your water heater, and open another HOT water faucet in a sink that is at the highest point in your house (NOTE:  Just a little water will flow out, since you have shut the water supply valve to your hot water heater in the step above).

6. Open the pressure relief valve at the top of the tank (you might want to place a rag or small bowl under the vent pipe to catch any water drops that might come out).

7. Open the drain valve on you tank and drain 1 to 2 gallons from the tank.  NOTE: The water coming out of the garden hose will be scalding hot so be careful that the water doesn't splash anywhere except in the bucket, drain, or outside.  As the water begins to drain out, you will probably notice some small scale or sediment in the water.

To re-fill the tank:

1. Close the drain valve and remove the garden hose.

2. Close the pressure relief valve at the top of the tank.

3. Open the valve for the cold water inlet to the tank, and you should start to hear the tank fill with water.

4. Watch the faucets that you opened in the house.  After you begin to get a steady stream of water from the faucet, shut that faucet.

5. For electric water heaters, turn the power back on, and for gas models, turn the thermostat on the water heater back to its ON position.

6. If you have a recirculation pump, then turn it back on.

7. Double check that the drain valve is tight.

TEST PRESSURE RELIEF VALVE:  The pressure relief valve is at the top of the tank, with a drain tube extending down from it.  To test the valve, with the water supply valve to your water heater in the open position (i.e., its normal operating position), place a bucket under the vent pipe for the valve, then lift the lever on the valve for a few seconds to let water flush out through the valve.  If little or no water flows out, or if the valve doesn't shut off, then replace it.  NOTE: The water coming out of the vent pipe will be scalding hot, so be careful that the water doesn't splash on you.

Relief valve testing:  The pressure relief valve is an important safety feature of your water heater.  If too much pressure builds up on the tank, the pressure relief valve opens up to relieve the pressure.  However, corrosion or scale build-up can prevent the valve from operating properly, potentially resulting in the tank exploding.  Therefore it is very important to test the pressure relief valve to ensure that it is operating properly.

 Maintenance Task #2:  Annual professional service and inspection

An annual professional inspection and service should be conducted by a trained water heater service person.  Items that they should include in their service and inspection are:

1. Inspect and clean burner assembly (gas and oil models).

2. Inspect exhaust flue (gas and oil models).

3. Flush out sediments by draining 1-2 gallons from the tank.

4. Test the pressure relief valve.

5. Drain the expansion tank (if it is a conventional-type tank) or re-pressurize the expansion tank (if it is a diaphragm-type tank).

6. Ensure the fuse is tight if the circuit includes an electrical fuse.

7. Check for evidence of leaks or corrosion.

8. Check the temperature thermostat on the tank.  If it is higher than 130°F you're likely wasting energy.  To test the actual temperature of the water, place a meat thermometer in a path of hot running water upstairs.

9. If the water heater is more than 10 years old, consider replacing the anode rod.  This rod is designed to protect the inside of your tank from corrosion.

This annual professional service is necessary for maintaining safety and energy efficiency of your water heater.

QUESTIONS & ANSWERS from "Ask-a-Wizard":

QUESTION from "Alice": 

Can you tell me how I drain the expansion tank (hot water systems)?  I have a spigot on the bottom of the tank.  What has to be done after it is drained?

ANSWER:

Alice:

PLEASE NOTE: water in a hot water system can be scalding hot. You need to be very careful working around your hot water system to keep yourself from being burned. If you are un-sure what you are doing, you should contact a trained professional.

Newer hot water systems typically have a diaphragm-type expansion tank, which is sealed, so it's not necessary to drain it. However, from time to time, these types of tanks need the air inside them pressured up. Older hot water systems typically have conventional expansion tanks that should be flushed out annually. You can recognize a conventional expansion tank because they will have two valves around them: a shutoff valve going to the furnace; and a drain valve on the bottom of the tank.

Here is the procedure for draining a conventional type expansion tank. First, close the shutoff valve that goes to the furnace. Position a bucket under the drain valve on the bottom of the tank. If you cannot position a bucket underneath the drain, then you can attach a garden hose to the drain, and run the other end of the hose to a bucket. Once the bucket is in place, then open the drain valve. The water should flow out, but if it doesn't, it may be necessary to use a wrench to open the vacuum-breaker plug (not all tanks have this plug) on the drain valve. After the tank has been drained, close the drain valve and vacuum-breaker plug; then re-open the shutoff valve going to the furnace.

Once again, if you have any concerns about doing this procedure safely, you should contact a professional heating contractor.

Hope this is helpful.

Regards,
Home-Wizard.com
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QUESTION from Art on 3/10/2008:

Other than the obvious advantage of "unlimited" hot water, are tankless water heaters more economical than a hot water tank? Assume that we're putting in a new system and typically do not run out of hot water (i.e. usage is less than 40 gallons at one time). If tankless systems are more economical to run, is electric or gas (we actually have LP) more economical?

ANSWER FROM HOME-WIZARD.COM ON 3/10/2008:

Dear Art:

Here is a webpage that describes the advantages and disadvantages of the various types of tankless water heaters (its about 3/4 of the way down the page):

http://en.wikipedia.org/wiki/Water_heater

Unfortunately, one of the disadvantages is the economics.

Hope this is helpful.
Home-Wizard.com
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QUESTION from madelarge on 2/11/2008:

My heat and water is ran by gas. The lights went out and the pilot light went out on the hot water heater. I was able to ignite it but the heat is not igniting. Both look like they are using the same gas line.

ANSWER FROM HOME-WIZARD.COM ON 2/11/2008:

Dear madelarge:

It sounds like you are still getting gas supply, since you were able to relight your hot water heater.

When you say that "the lights went out and the pilot light went out", did you mean that the power in your home went out? Or did you mean that the pilot lights went out? If it was a power failure, have you checked whether the fuse or circuit breaker has tripped on your furnace? Are you exactly following your manufacturer's recommended procedure for relighting your furnace, (which could be a different procedure from your water heater)? The relighting procedure should be fastened somewhere on your furnace. It could also be that the thermocouple has failed on your furnace.

Remember, if you smell gas in your house, do not turn any lights on or off, and do not try to shut off the gas leading to the furnace. Get out of the house, leaving the door open, and immediately call the gas company or the fire department to report a leak. Do not re-enter your home. Do not use the phone or your cellphone from inside the house. 

Home-Wizard.com
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QUESTION from dan on 9/3/2008
My hot water heater is 12 yrs old. If the temp. setting is too low will there be days when the water is hotter than others. Also should the heating element(s) be removed and cleaned peiodically

ANSWER FROM HOME-WIZARD.COM on 9/3/2008
Dear Dan:

If the temperature setting on the thermostat on your hot water heater is too low, then you might find your home running out of hot water from time to time. Also, you may find that it takes longer for your hot water to recover after large hot water uses (baths, showers, dishwasher, etc.). But on the other hand, lowering your temperature setting on your hot water heater can help you save energy.

However, if your thermostat is operating properly, then I can't see a reason why some days would have water hotter than others, just because you set the temperature lower.

Regarding your second question about whether the heating element (or elements, if your unit has both higher and lower heating elements) of your water heater should be removed and cleaned routinely, the answer is that the heating element(s) is usually just removed and cleaned when it shows evidence of failure. You should routinely backflush your water heater (see our Maintenance Library) to remove sediment and scale, and the frequency will depend on factors such as the hardness of your water and how you use hot water in your home. But removing a heating element is a fairly involved job, and if your water heater is operating properly, it's not something that one would do without cause, that is, if your delivery and recovery of hot water has not declined significantly.

Hope this is helpful.
Home-Wizard.com
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QUESTION from Kat Bannister on 9/7/2008
I need to purchase an expansion valve for my hot water heater. it is old style and i cannot afford to replace it with one of those new expansion tanks. Can you help me find and expansion valve to replace this with or let me know any way to stop the leak until I can afford a plumber?

ANSWER FROM HOME-WIZARD.COM on 9/7/2008
Dear Kat:

If I understand your situation correctly, it sounds like your pressure relief valve on our hot water heater is leaking water out through the discharge tube, right? And if I had to assume, your home has a back flow prevention valve on the water supply to your house, and you do not have an expansion tank on your hot water system, correct?

First to answer your first question, you can purchase a pressure relief valve at most plumbing supply businesses. Here's an example of an online distributor, although we do not have any experience with them: http://www.plumbingworld.com/heatingrelatedproducts.html

But regarding your question of stopping the leak, it is VERY IMPORTANT to note that your water heater's pressure relief valve may be leaking because it is doing its job. That is, that the water pressure in your hot water heater may be too high, and it is venting water to help get the pressure down. An over-pressured water heater can be VERY DANGEROUS, as they have been known to explode.

One question is whether this leaking from your pressure relief valve is because this valve is failing? Or is it because you have a back flow prevention valve on your system, but you do not have an expansion tank . . . and as the water heats and expands, it has no place to go, so it causes your pressure relief valve to open? Or is it because your tank is operating at too high of a pressure?

Here is an online article that describes the operation of water heater pressure relief valves, that you might find helpful: 

http://www.factsfacts.com/MyHomeRepair/PressureRelief.htm

Since your pressure relief valve is an important safety feature of your water heater, we have to advise that you should have a trained professional evaluate it as soon as possible.

Probably not what you wanted to hear, but we hope this is helpful for you.
Home-Wizard.com
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QUESTION from mike on 9/19/2008
hot water tank leaking at the drain valve put a pipe wrench on it put a little pressure on it didnt move afraid of it snaping off and then have to buy a new water heater or it going to be very tight

ANSWER FROM HOME-WIZARD.COM on 9/20/2008
Dear Mike:

If your question is whether you should use your pipe wrench to force off a drain valve on your water heater that is frozen, yes, you need to be careful not to snap it off.

Between the heat, water, sediments, etc., this valve can get quite frozen.

Have you tried spraying penetrating oil all around the treads of the valve, and then letting it set for several hours (even overnight if you can). Also, after the penetrating oil has been allowed to work its way in, when you put your wrench on it to untighten it (and remember: "lefty loosy", "righty tighty"), do NOT just pull hard on the wrench, instead use quick jerks on the wrench, like pounding the end of the wrench with your hand. These quick jerks on the wrench can do better at breaking corroded threads that just a long sustained pull.

And remember SAFETY: I assume that you have first drained all of the hot water out of your tank before removing the drain valve.

Hope this is helpful.
Home-Wizard.com 

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QUESTION from Ron on 11/1/2008
we have water circuit heat....it continues to run water thru the pipes for a long while (which can be heard in the baseboards of the rooms), before actually just working and warming the house like it should,when you cut hot water on the water heater makes a rattling sound like it isn't full could it just be my water heater on the blink and not my water circuit unit in all?....thanks for any info you can provide

ANSWER FROM HOME-WIZARD.COM on 11/1/2008
Dear Ron:

I suspect that the problems with your hot water heater and your baseboard heating system are not directly related.

Let's start with the problem you are having with your water heater first. Its a bit difficult to diagnose problems with a noisy water heater without actually hearing the sound and physically seeing when it is occurring, but here are a few thoughts which will hopefully be helpful for you. If you are hearing a rattling sound when you are running your hot water, then the problem with your water heater may be with check valve type nipples installed on the top of your water heater, if you have them. If you have them, they are a good have because they can save some energy, but they also can be very annoying.

On the other hand, the noise that you are hearing from your water heater could be the sound of boiling water caused by excessive build-up of sediment in the bottom of your tank. This sediment could be causing the bottom of your tank to overheat and water to boil, which could be the noise that you are hearing. The remedy for this is to routinely backflush your water heater as described on the "Water Heater" page of our online Maintenance Library:

http://www.home-wizard.com/maintenance/waterheater.asp

Now, regarding your first problem, it sounds like your baseboard radiators are heating up fine, but you think that it is circulating water for too long before it actually heats up the baseboard radiators. Am I understanding you correctly? What I'm wondering is if whether the sound that you are hearing in your baseboard heating system pipes is the sound of trapped air that is circulating in with the water, and causing your system to operating inefficiently. If you haven't tried it already, I would suggest that you bleed all of the air out of your system.

Hope this is helpful.
Home-Wizard.com
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QUESTION from bhleske on 9/25/2009
How much water should flow out the bottom cold water relief valve in an electric hot water system.we seem to be losing a fair bit more than 8 gallons

ANSWER FROM HOME-WIZARD.COM on 9/25/2009
Dear bhleske:

Just a couple of questions so that I can better understand your situation:

1) how do you mean the "bottom cold water relief valve"? Are you referring to a drain valve on the supply side? Or the pressure relief valve (which should actually be on the hot side)?

2) when you say you are "losing more than 8 gallons," over what time period are losing this volume? Or do you mean that this how much comes out when you drain the tank?

If you can let me know on these questions, hopefully I will be able to help you.

Sincerely, 
Home-Wizard.com
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QUESTION from bhleske on 9/27/2009
Dear Home-Wizard;

Attached is a photo hopefully to clear things up. The black knob is the non return valve for cold water inlet to tank

Water loss is when heater is heating.

Regards

ANSWER FROM HOME-WIZARD.COM on 9/27/2009
Dear bhleske:

Thank you for sending the photo, that was very helpful.

There are two reasons why a pressure relief value could be leaking on your water heater:

1) the valve has either gone bad, or has a particle of sediment from the tank that is keeping it from seating properly; or 

2) the pressure in your tank is exceeding the relief point.

Regarding your pressure relief valve, you might want to try lifting the lever in the valve to allow it to discharge (be careful, as the water coming out can be scalding hot) so it can flush out any debris. Alternatively you may have to replace the valve. These valves are usually not very expensive, but they can be hard to remove.

And regarding the pressure in your tank being too high, if you don't already have one, then you may need to have an expansion tank installed. The other cause could be that the line pressure from you main supply may have become too high.

Hope this is helpful.
Home-Wizard.com
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