Hot water heaters are prone to making many different noises when they're running. Some of those noises can be worrisome, particularly if you're not sure what's causing them. One common sound you might hear from your hot water heater is popping. Naturally occurring mineral deposits in the water can settle to the bottom of the tank, and when air bubbles in the water disturb those minerals, it causes the popping noise. Here's a look at what you should know about water heater popping and how to deal with it.

How Do I Get Mineral Deposits in My Water Heater?

When water flows through the ground, it absorbs minerals from the soil that it passes over. Even municipal water treatment processes don't typically remove these minerals, so they're left in most every water supply. When water is heated to the temperatures used by a hot water tank, it causes those minerals to group together.

How Do The Mineral Deposits Cause Popping?

Water tanks go through natural heating and cooling phases, and when the water cools, those groups of mineral particles will fall to the bottom of the tank, because they're heavier than the water. When the next warming cycle starts, those minerals can be stirred up from the bottom of the tank, making them bounce around and collide with each other as a result of air bubbles.

How Do You Get Rid of These Mineral Deposits?

The best way to deal with mineral deposits in a water tank is by flushing the whole tank. If you're going to do it yourself, though, it's important you know the proper steps so you don't damage the tank.

  1. Disable It: Turn off the power to the water heater if it's electric. If it's a gas water heater, turn the control to "Pilot" instead.  
  2. Drain It: Turn the valve on the incoming water supply line to close the line. This prevents more water from being added to the tank. Let the water in the tank cool for a few hours so you don't risk burns.

    Then, connect a long drain hose to the lower drain valve at the bottom of the water heater tank. The drain hose should screw onto the drain valve so it stays in place. Put the other end into the sink or run it out the door and away from the house. Either way gives the water somewhere to drain to. Then, open the pressure release valve at the top of the water tank followed by the drain valve at the bottom. Wait for the water to finish draining and close the drain valve.  
  3. Clean It: Remove the hot water pipe connected to the top of the tank. Put a thin funnel into the opening and pour a tank cleaner into the funnel. Look for a tank cleaner that removes lime scale for the best results. Make sure you follow the instructions on the cleaner carefully, as the ratio of cleaner to water changes depending on the brand.

    Add the proper amount of cleaner to the tank based on the tank size then reconnect the water line. Turn on the water so that the tank fills. When the pressure release valve stops passing air through, close it. Turn the water heater on and let it run for the recommended time according to your cleaning product. Then, turn it off and let it cool again.  
  4. Flush It: Repeat the entire drain process to get rid of the cleaning solution from the tank. Then, run water through the tank until you see it coming out of the drain hose clear instead of the cloudy, white color that it will have when it first starts to drain. Clear water indicates that the tank is clean. Disconnect the drain hose, close the valves and restore your tank to normal operation.

If you aren't comfortable doing this work on your own, you may want to talk with a local technician about flushing it for you. He or she may also recommend that you install an in-line water softener to remove many of these minerals if you're having persistent problems. Check out sites like for more information.