What Is White Stuff In My Water Heater?

Contrary to popular belief, having white stuff in your water heater is not always a sign of something gone wrong. In fact, there are a variety of reasons why white stuff might be present in your water heater—some of which may be quite harmless.

If you’ve ever looked inside your water heater and asked yourself, “What is this white stuff?” then this article is for you! Let’s take a closer look at what causes this white stuff and what you can do about it.

What is the White Stuff in My Water Heater?

If you ever find something white floating around in your water heater, you may be wondering – what is it? Well, the answer could range from harmless to potentially harmful, but the good news is that you can take steps to identify and remove whatever is causing the issue.

What Could it Be?

There are several possibilities as to what could be causing the white stuff in your water heater:
  • Lime deposits: Minerals such as magnesium and calcium build up over time and create a white, powdery deposit.

    This is usually harmless and can usually be removed with a water softening system.

  • Algae: Algae tend to thrive in warm, damp environments and can grow in water heaters, creating a slimy, green/black mess.

    This can be harmful as it can otherwise contain minerals, lead, or other hazardous materials.

  • Rust: Rust is a sign of corrosion, and it can form from a combination of iron, oxygen, and water. This can discolor the water and the walls of the water heater, and is a sign of a bigger issue in terms of the metallic components inside the heater.

  • Bacteria: Bacterial growth can occur inside of the water heater, especially if the temperature isn’t hot enough or the water isn’t circulating. Bacteria can look slimy and slimy, and can cause serious health risks.

What Can I Do?

Once you have identified what is causing the white stuff in your water heater, you will need to take the necessary steps to remove it.
  • Lime deposits: For this issue, you can use a water softening system or a vinegar/baking soda mixture to remove them from the tank.

  • Algae: You can either pour a chlorine/baking soda solution or bleach in the tank and let it sit for a couple of hours before draining and refilling the tank.
  • Rust: You can use a rust remover to remove the rust from the tank, but it is important to note that this is not a permanent solution and the rust will likely come back.
  • Bacteria: The best solution is to drain and refill the tank and keep the water temperature at a high enough level (typically 140 degrees Fahrenheit) in order to prevent bacteria from growing again.


If you ever find a white stuff in your water heater, take the time to identify what is causing it before attempting to remove it. This can help ensure that you take the proper action and prevent any future damage to the tank or to your health.

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