If your water heater has started making a popping or gurgling sound, it’s not in your head. You shouldn’t ignore this. That weird noise means something is going on inside the tank. You still get the same hot water, but bigger problems can arise later.
What May Cause a Gurgling or Popping Sound Coming from a Water Heater?
Popping or gurgling sounds coming from a hot water heater aren’t normal, but they are common. The sound you’re hearing is usually the result of water bubbling beneath sediment buildup inside the tank. There can be other reasons for this issue, so let’s tell you all about it below:
Sediment Buildup from Hard Water
This is the most frequent reason behind that popping sound. As you use the water heater, minerals (calcium and magnesium) settle at the bottom of it, especially if you have hard water. When the burner heats the tank, water gets trapped beneath the layer of sediment and forms bubbles that make that popping or rumbling noise as they break through.
If the sediment layer gets thick enough, it can also lower the performance of your hot water heater, make it overheat, or even damage the tank lining.
Limescale on Heating Elements (Electric Heaters)
In electric water heaters, the heating elements are directly submerged in the water. Minerals in the water can collect and harden around the element, and they form a crust. When electricity heats the element, the scale traps small air pockets that burst with a crackling or popping sound. If ignored, it can reduce the heater’s performance.
Steam Pockets/Trapped Air
Sometimes, these sounds pop up from steam bubbles. These bubbles form where water is superheated in the heater, and the same sediment traps water in pockets. This causes it to boil unevenly. Then, these bubbles rise and burst, and make the noise you are hearing.
Another reason can be the air getting trapped in the water heater after maintenance or during refills.
Is Popping In a Water Heater Bad?
The popping sounds coming out of your water heater are more of a warning sign. It’s not going to burst, but it’s telling you that it isn’t running as it should. The sediment builds up inside the tank and acts like a layer of insulation between the burner and the water. This forces the burner to work harder to heat the same amount of water, which increases wear on the tank and shortens its lifespan.
If you don’t fix this, the tank may overheat, which leads to:
- Pressure buildup
- Efficiency loss
- Higher energy bills
In electric models, scale-covered heating elements can eventually burn out. So while the noise itself isn’t dangerous, what’s causing it definitely needs attention before it turns into a costly repair—or worse, a full replacement.
How Do I Stop My Hot Water Heater from Popping?
Use Vinegar to Remove Scale (Electric Models)
For electric heaters, scale often forms around the heating elements. You can remove some of that scale by draining the tank and filling it halfway with vinegar. Let it sit for a few hours. The acidity helps dissolve the mineral crust.
Be sure to flush the tank thoroughly afterward to remove any vinegar residue before turning the heater back on.
Bleed Trapped Air
If you recently had the water turned off or completed maintenance, it’s possible the air pockets could be trapped in your lines. There’s an easy fix for this. Just run your hot water taps for several minutes to help bleed the air. This can reduce bubbling or hissing sounds caused by air escaping as water heats up.
Flush the Tank
If you haven’t flushed your water heater in over a year, that’s a good place to start. Flushing removes sediment from the bottom of the tank, which is usually the source of the popping noise.
Here are the DIY steps for it:
- First things first, turn off the gas or electricity to the heater.
- Now let the water cool down: give it an hour or more.
- Then, plug one end of a garden hose to the drain valve, which you’ll find at the bottom of the tank, and place the other end of the hose somewhere where the sediment and water can safely drain.
- Next up, turn on a hot water tap in your home to keep air flowing through the system, then open the drain valve on the water heater.
- There’s a tab on the pressure relief valve; pull it so that the water in the tank gets moving and starts to drain.
- Once the tank is empty, turn on the cold water supply to stir up remaining sediment, then drain again.
- Finally, close the valve, disconnect the hose, and restore power.
You should do this once a year to keep the water heater clean and quiet.
Inspect the Anode Rod
The anode rod stops rust from building up inside the tank, but can also influence scale formation. If it’s worn out, sediment can collect faster. If you’re already draining the tank, it’s worth checking the rod. A plumber can replace it if needed.
Pro Tip: If you live in an area with hard water, installing a water softener can prevent the mineral buildup that causes popping. A softener removes calcium and magnesium from the water before it reaches your tank, and lowers the chances of sediment forming at the bottom or coating the heating elements. While not a quick fix, it’s a long-term solution that can extend the life of your plumbing system.
How Much Does It Cost to Flush a Hot Water Heater?
The cost to flush a water heater depends on the size of it. Of course, if you’re confident handling the task, it’s free except for your time and a garden hose. But if you prefer to call a pro, here’s what to expect:
- For a 30-gallon tank, the average cost ranges from $90 to $120.
- A 50-gallon tank will usually cost between $120 and $160.
- For a 70-gallon tank or larger, expect to pay $180 to $250, depending on your area and the complexity of the job.
Plumbers may also charge extra if the drain valve is corroded or hard to access, or if additional sediment removal is needed. Although it may seem like a steep price for maintenance, regular flushing avoids much higher costs down the line, like replacing a burned-out element or the entire unit due to rust damage.
Conclusion
A popping sound coming from your water heater might seem harmless, but it’s actually asking for attention. Most of the time, it means sediment or minerals have built up inside the tank, and you can take care of it early through flushing, softening your water, or checking the elements, which can save you a major repair bill.
If the noise won’t go away or you’d rather let someone else handle it, California Coast Plumbers is just one call away. We offer expert water heater maintenance and repairs done quickly, cleanly, and at honest rates. Don’t wait—get your water heater back to quiet, efficient performance today.