6 Signs Your Water Heater Is About to Fail

Shannon Llewellyn
Updated July 30, 2021
Running water from a faucet over a sink
Fabian Schmidt / EyeEm/EyeEm via GettyImages

Learn the warning signs of a water heater on the fritz—and what to do about it

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Sometimes a lagging water heater is simply the result of too many hot showers or back-to-back loads of laundry. However, there are some instances where it needs a fix so your water heater keeps giving you hot water on-demand. Let’s walk through six signs your water heater is about to fail and how you can keep it from happening.

Note: Water heaters can be dangerous if not approached properly. If you attempt to diagnose or repair a gas water heater yourself, extinguish the pilot light, and for an electric unit, unplug it or flip the circuit breaker. Wear goggles and protective gloves, too.

1. Taps or Knocking Sounds

If you hear tapping or knocking sounds coming from your water heater, there’s a good chance you have sediment buildup, which could create tiny tears in the metal that ultimately cause leaks that send your hot water heater to appliance heaven. Luckily, there’s a chance you can save your appliance by draining it. And thankfully, draining a hot water heater is easier than you think. Or, calling a professional will run you about $100 and might be totally worth it if you aren’t comfortable with DIY-ing the project on your own.

2. Not Enough Hot Water

Are you and your family drawing straws for showers and baths because there’s never enough hot water on demand? If you have a growing family or have added a bathroom, maybe your current hot water isn’t actually meeting your needs and it’s time for a larger unit .Water heater sizes are based on the gallons of water they hold and demand. In general, a 30-gallon capacity is fine for one person; two people manage nicely on a 40-gallon capacity, and a 50-gallon capacity water heater means no more staggering showers for larger families. Explore the option of upgrading to a water heater unit that not only serves your current needs but can last for years to come.

3. Temperature Fluctuations

Your hot water heater’s thermostat should stay where you program it, but sometimes they cool off too much. In some cases, it’s simply a matter of having a pro replace the thermostat or heating element for $150 to $200. How can you test it? Adjust the thermostat and use a marker or piece of tape to make a small mark. It’s possible the thermostat is unstable and changes slightly on its own. 

4. Leaks

A leaking water heater needs immediate attention. Best case, it could be that one of the connectors, pipes, or screws just needs a little tightening. Some condensation gathered around the bottom of the unit can be OK depending on the humidity level where you live, but clearly visible puddles or active leaking means it’s time to call a plumbing professional to determine if it’s a water tank issue or a connection issue. 

5. Cloudy or Foul-Smelling Water

Washing dishes, your hair, or your dog is far from fun if your water stinks like rotten eggs or looks dirty. This likely means rust and bacteria are not being eliminated by the built-in anode rod. Before you make that call to a professional, however, make sure the foulness is actually coming from your water heater unit and not the actual water supply to your home. Run a clear glass of cold water next to a clear glass of hot water. If the cold water runs clear from the tap, it’s a water supply issue. But, if the glass of hot water is murky, it’s a water heater issue. Try draining the tank first. If that’s unsuccessful, you’ll need the anode rod replaced by a pro.

6. It’s More Than 10 Years Old

You may love your historic home but if your water heater is just as historic (as in double digits years), you may have to replace it, especially if it’s exhibiting one or more of the issues above. Thankfully, the range of newer models are far more durable and energy efficient. Many utility companies have programs that offer discounts on purchasing, installation, and rebates. 

Things to Consider When Replacing Your Water Heater

If you’re considering purchasing a new water heater, factor in the following:

  • Your family’s usage in terms of the amount and frequency of showers, baths, dishes, and laundry.

  • Your budget—the average cost to replace a water heater is $1,200. 

  • Your trusted plumbing professional can help you figure out the best water heater unit for your needs.

  • Any rebates or incentives from your local power or water utility.

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