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Common Water Heater Problems

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Fortunately, tank-type water heaters are fairly simple products. While all their components are important, there are relatively few of them when compared to other appliances. Most fixes can be made on your own without spending a fortune. Though if it’s a problem with the water tank itself, a new water heater is usually the only solution.

Below are some of the most common issues homeowners may experience in regards to water heaters and hot water. To make it easier for you, there are sections for both Electric and Gas water heaters. Troubleshooting a problem is essentially a process of elimination so work your way down the list until you find the issue that most resembles what you are experiencing.

As always, if you are not completely comfortable with making the repairs yourself, please call a professional plumber.

Electric Water Heater Troubleshooting

(Click to jump to GAS water heater problems)

(click to enlarge)

Water Leaking From the Top

If you believe you have a leak near the top of your electric water heater, it could be one of a few things. The cold inlet or hot outlet pipes may be loose, the T&P valve may have failed, or inlet valve may be leaking. All are easily fixed. For more information, see Water Heater Leaking from the Top.

Water Leaking From the Bottom

An electric water heater that’s leaking from the bottom is typically because of normal condensation, a leaking electric heating element gasket, or a small amount of water being expelled through the overflow pipe because the T&P valve is opening to release excess pressure in the tank.

In some cases, the actual tank is leaking and the only fix is to replace the water heater. For more information, see Water Heater Leaking from the Bottom.

No Hot Water

Water in an electric water heater is heated by two heating elements (in most cases). The most common reason for absolutely no hot water is that the circuit breaker has tripped and you should first check the breaker box.

If that’s not the cause then the heating elements may have failed and need replacement. It may also be an issue with the limit/reset switch on the thermostat. It may have tripped due to the water being way too hot or simply failed and needs replacement.

Not Enough Hot Water

Not having enough hot water is most likely due to an issue with the thermostat. It may be as simple as adjusting the desired water temperature on the thermostat for the particular heating element.

On electric models, the thermostat is usually hidden behind an access panel on the side of the tank and a layer of insulation. Unlike gas models, an electric thermostat is set at the factory and not intended to be changed but is sometimes necessary to do so.

During the cold winter months, you may need to slightly raise the thermostat temperature since the hot water gets cooled quicker through colder pipes as it travels through your home’s plumbing.

Other possible reasons for not having enough hot water include a faulty thermostat, faulty element, loose wiring, or simply a water heater tank that’s too small for your needs. See “What size water heater do I need” for more info.

Water is Too Hot

Again, this is likely related to the thermostat(s) where the temperature is set too high. Simply gain access to the thermostat and adjust as needed. This may also be needed when transitioning from cold to warm seasons. For our recommended temperature setting, click here.

If you cannot lower the water temperature low enough, you may need to replace your thermostat or there may be some type of wiring issue (recommended to call a pro if the later).

Water Takes Too Long to Reheat

This is one of the downsides with electric water heaters. On average, recovery time (time it takes to reheat entire supply of water) on an electric model is double that of a comparable gas model. The amount of time it takes to heat up water can vary quite a bit between different models. Newer is usually better.

That said, if it’s taking longer than usual for the hot water to recover, there may be an issue with the heating elements (including sediment build-up on them) or thermostat and those parts may need to be replaced.

If your household tends to use more hot water now than a few years ago, you may want to consider investing in a new model with a larger capacity tank, a tankless model, or installing a point-of-use water heater that’s close to the water source you use the most (ie: the shower). But we recommend to do some research on the tankless vs tank water heater comparison.

Low Hot Water Pressure

Most often, those reporting to have low hot water pressure have an older home with 1/2-inch diameter galvanized piping that enters and leaves the water heater. Since water pressure is automatically limited, the only solution is to install modern 3/4-inch piping which allows more water to flow through.

Sediment, calcium-deposits, and rust inside your plumbing or sink aerators may also contribute to low hot water pressure.

Water Heater is Making Strange Noises

If you hear popping, hissing, banging, knocking, or other strange noises from your water heater, it’s most commonly due to scale build-up on your heating elements or too much sediment build-up in the bottom of the tank.

Other causes of noises include a leak somewhere, too much pressure inside the tank, or noisy pipes because of normal expanding/contracting. When your water heater is making noise, it’s often harmless but should always be looked into for piece of mind.

Dirty or Rusty Colored Water

Rusty hot water is often a sign of corrosion of the anode rod or even tank itself. If left untreated, your water heater will most likely need replacing once the corrosion gets serious enough for the tank to develop a leak. Replacing the anode rod is easy to do and can add years to your water heater.

If the water is not rusty but dirty or discolored, it may be because of scale build-up on the heating elements or sediment that’s making its way into the hot water outlet.

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Smelly Hot Water

Most likely, smelly or stinky hot water is due to bacteria in the tank. Homes which use well water as their water source are more susceptible to their water giving off a foul odor. Periodic flushing of the water heater may temporarily help but to actually fix the sulfur or rotten egg smell from your hot water, you’ll likely need to replace the anode rod. Better yet, consider a powered anode rod which will get rid of the smell and last the longest.

A quick fix may be to increase the thermometer temperature to about 140 degrees to kill off any remaining bacteria.

For more detailed information on troubleshooting an electric water heater, watch the video below:

Gas Water Heater Troubleshooting

(click to enlarge)

Water Leaking From the Top

Same as with an electric water heater, you should first check the cold water inlet and hot water outlet pipes and connections to make sure they are not loose. A faulty or loose temperature and pressure relief valve or inlet valve may also be the cause of leak.

See Water Heater Leaking from the Top for more information.

Water Leaking From the Bottom

When you see water that appears to be leaking from the bottom of a gas water heater, it could be because of condensation (try turning up the thermostat), a leaking or loose drain valve, or the T&P valve draining some water through the overflow pipe due to tank overpressurization.

If the leak is from the water heater tank due to corrosion, replacement of the water heater is necessary. See Water Heater Leaking from the Bottom for additional information.

No Hot Water

The very first thing to check is if you have gas flow and that your pilot light is on. If yes, the issue may be with the thermocouple which is not correctly sensing that the pilot light is on and in turn does not ignite the gas. The thermocouple may need to be replaced (or simply cleaned).

If you have a newer style water heater with electronic ignition, check your breaker box to see if the circuit breaker is tripped. See here for more info.

Not Enough Hot Water

Some reasons for not having enough hot water or running out of hot water too soon include not having the thermostat set at a high enough temperature (especially in the winter months), a faulty thermostat, or a broken or damaged dip tube which allows the incoming cold water to mix with the hot water at the top.

Sometimes not enough hot water is simply because you have a water heater tank that’s too small for your needs. Even though you may have a 40 gallon tank, only about 28-30 gallons of it may be usable hot water at a time. Upgrading to a larger water heater or a tankless model may be in your future.

Water is Too Hot

Most likely, you have the thermostat set too high. This is most common when transitioning to the warmer Spring and Summer months and forgetting to set back the temperature after raising it to account for the colder Winter temps. Less likely is a faulty thermostat that needs replacement.

Do you have problems with water heater installation? Then this article is just for you.

Water Takes Too Long to Reheat

If it feels like your gas water heater recovers too slowly, the thermostat may be set too low, the burner orifice may be too dirty or clogged and requires cleaning, the gas pressure may be too low, or the vent flue may be too dirty and also require cleaning.

For many, it’s simply a matter of having too small of a water heater tank for their family’s needs and it’s never given a chance to fully recover.

Low Hot Water Pressure

If you have an older home, there’s a good chance you have the smaller 1/2-inch diameter galvanized piping throughout your home. This greatly reduces the amount of hot water than can flow through your home’s plumbing.

Unfortunately, the only way to get noticeably higher hot water pressure is to switch out to the newer 3/4-inch piping that’s used in today’s homes. Definitely not a small task.

You may be able to slightly increase water pressure by cleaning out sink aerators or shower heads which tend to get clogged over time. Also, make sure your water inlet valve is fully open and not partially closed.

Pilot Will Not Light

When you know exactly how to light a pilot light on a water heater yet it won’t light, there are a few possibilities as to why. Either the pilot light orifice or tube is clogged or needs replacement, the thermocouple is loose or faulty, there is air in the gas line, or the gas valve is defective.

Pilot Will Not Stay Lit

Just as annoying as a pilot light that won’t light, is a pilot light that frequently goes out. Often, thermocouple replacement is necessary but there are other reasons if your pilot light keeps going out. Other possibilities include a bad gas valve or partially clogged vent which can cause downdrafts that blow out the pilot light.

Burner Does Not Stay Lit

A burner that at times goes out or produces an unusual, higher or lower than usual flame or even a whistling sound, is most often due to dirty or clogged burner orifices. As with the pilot light, a faulty thermocouple or dirty vent may also be the cause of the problem.

Water Heater is Making Strange Noises

Same as an electric water heater, hissing, popping, knocking, or banging noises can sometimes come up. On gas models, this is typically due to sediment build up in bottom of the tank, expanding/contracting piping which rubs against wood framing within the walls, or dirty/clogged parts which gas flows through.

Rusty Colored Water

Once again, corrosion of the anode rod or the inside of the water tank itself is usually to blame. While replacing the anode rod isn’t complicated or expensive, the bigger problem lies if the tank shows signs of corrosion. It’s then only a matter of time before a leak develops and a new water heater (see also ‘What To Do If You Notice Your Water Heater Leaking’) will be needed.

Smelly Hot Water

Likely due to bacteria build up inside the tank. Simply turning up the thermostat to about 140 degrees should kill off the bacteria but a full clean-out of the tank with chlorine bleach may be necessary. If the smell comes back, the anode rod is likely at its end of life and will need replacing.

Are you looking for a little bit more specific solution?

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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