A water heater making popping noise is one of the most common things homeowners call us about, and it usually shows up at night when the house is quiet. The good news is that it is rarely an emergency. The better news is that it is often fixable, and catching it early can add years to your water heater’s life.
Here is what is going on inside the tank, what you can safely do about it, and when it is time to call a plumber.
Popping usually means sediment has built up at the bottom of the tank. A yearly flush often fixes it, and a tank that is 8 to 12 years old may be better replaced than repaired.
What Causes a Water Heater Making Popping Noise?
Almost every time, the culprit is sediment. Water carries minerals like calcium and magnesium, and as your tank heats water over and over, those minerals separate out and settle at the bottom as a layer of grit and scale. Over months and years, that layer gets thicker.
Here is where the noise comes from. The burner or heating element sits at or near the bottom of the tank. When sediment covers it, water gets trapped underneath the layer. That trapped water overheats and turns to steam, and the bubbles burst up through the sediment. That is the popping, rumbling, or crackling sound you hear.
Both gas and electric tanks do it. Gas tanks tend to be louder because the burner heats from underneath, but an electric tank with scale on its lower element can sound just as bad.
Is a Noisy Water Heater Dangerous?
Usually not, but it is not harmless either. Sediment makes your water heater work harder to heat the same amount of water, which can raise your energy bill. The constant overheating at the bottom also stresses the tank over time, which can shorten its life or eventually lead to a leak.
Call a plumber right away if you notice water pooling around the base of the tank, rusty or discolored water from the hot tap, or a sound that is getting much louder quickly. If you have a gas water heater and smell gas, leave the house and call 911 or your gas utility from outside. Do not try to troubleshoot that one yourself.
How to Fix a Popping Water Heater
For most tanks, the fix is a flush, which clears the sediment out of the bottom. If you are comfortable working around your water heater, here is the basic process:
- Turn off the power. Flip the breaker for an electric unit, or set a gas unit to pilot or off.
- Shut off the cold water supply valve to the tank.
- Connect a garden hose to the drain valve near the bottom and run the other end to a floor drain or outside.
- Open a hot water tap somewhere in the house so air can get in, then open the drain valve.
- Let it drain until the water runs clear. It may come out cloudy or gritty at first.
- Close the drain valve, remove the hose, and close the hot tap. Turn the cold water back on and let the tank fill completely before you restore power.
Be careful, because the water inside is hot enough to scald you. And if the drain valve will not flow, or only dribbles because it is clogged with sediment, stop there. Forcing it can damage the valve and make a much bigger mess.
Should You Repair or Replace It?
Age matters. Most tank water heaters last roughly 8 to 12 years. If yours is in that range and the popping comes back soon after a flush, the sediment may have hardened into a layer that a simple flush cannot remove. At that point, replacing the unit usually makes more sense than paying for repeated repairs. The U.S. Department of Energy has a helpful guide to water heating if you want to compare your options.
It is also time to think about replacement if you see rust around the tank, you run out of hot water faster than you used to, or you have already had it repaired more than once.
Put a reminder in your phone to flush the tank every fall, right when you change your smoke detector batteries. It is easy to remember, and it adds years to the tank.
How to Keep It From Happening Again
The best prevention is a yearly flush. It takes a plumber less than an hour and costs far less than a new tank. It is also worth having the anode rod checked, since that rod protects the inside of the tank from rust and wears out over time. If you would rather not keep track of any of this, our maintenance plans include water heater checks so small problems get caught early.
Water Heater Help in Boulder County
If your water heater is making popping noises and you want a straight answer on whether to flush, repair, or replace, we can help. We serve Boulder, Longmont, Lafayette, Louisville, Erie, Superior, Niwot, and Gunbarrel, and every technician is licensed with the State of Colorado. See our water heater repair and installation page, or call us at (720) 940-3661. We will tell you what is going on and give you a clear price before any work starts.