How to Remove Limescale/Calcium Buildup from a Toilet


Removing limescale or calcium buildup from a toilet is essential for maintaining cleanliness and proper flushing. Here’s a brief summary of how to do it:

  • Gather Supplies: You’ll need white vinegar, a toilet brush, a pumice stone (optional), and a cloth or sponge.
  • Turn Off Water: Locate the shut-off valve behind or near the base of the toilet and turn it off. Flush the toilet to empty the tank and bowl.
  • Apply Vinegar: Pour a generous amount of white vinegar into the toilet bowl, making sure to cover the limescale buildup completely. Let it sit for at least an hour or overnight for stubborn stains.
  • Scrub: Use a toilet brush to scrub the bowl, focusing on the areas with limescale buildup. The acidity of the vinegar will help dissolve the deposits.
  • Pumice Stone (Optional): If the limescale is particularly stubborn, you can use a wet pumice stone to gently scrub the stains. Be cautious not to scratch the porcelain. Wet the pumice stone and the stained area before use.
  • Flush: Turn the water supply back on and flush the toilet several times to rinse away the vinegar and loosened deposits. Repeat the process if necessary.
  • Inspect and Repeat: Check the toilet bowl for any remaining limescale. If some spots persist, repeat the vinegar and scrubbing process until the stains are gone.
  • Regular Cleaning: To prevent future limescale buildup, regularly clean your toilet with a toilet bowl cleaner or vinegar and keep the bowl clean to deter mineral deposits from accumulating.
  • Consider Water Softening: If limescale is a recurring issue due to hard water, consider installing a water softener for your entire plumbing system to reduce mineral content.

The best way to prevent calcium buildup in toilets, tubs, sinks, faucets, drains and water pipes is by installing a water softener. Negatively charged beads in the water softener attract positively charged minerals like calcium and iron, and that is how they are able to pull the minerals out of the water.

Unknown to most people, calcium buildup is usually responsible for weak flushing toilets, or toilets that will not flush all the way. You may therefore find yourself holding the handle down too long for the toilet to flush completely.

If you look underneath your toilet bowl rim with a mirror, you will see small holes which are evenly spaced throughout the rim. When you flush the toilet, water comes out through these holes.

Calcium deposits can badly clog these holes, restricting the flow of water from the tank to the bowl. Some toilets have a siphon jet at the bottom of the bowl which can also be clogged by the calcium in the flush water.

As you remove calcium deposits from the toilet bowl, don’t forget to remove the one clogging rim holes and the siphon jet. That way you will end with a clean and strong flushing toilet.

Vinegar and baking soda (or borax) are septic-safe, safe for your plumbing and eco-friendly as well. You can as well opt to use chemical drain cleaners to get rid of the limescale.

Although chemical drain cleaners are effective in removing calcium buildup in toilets, they are toxic, will kill the good bacteria in your septic tank and are bad for the environment. Muriatic acid, which is the number one choice for this job is bad for your plumbing and can burn your skin if it comes into contact with it.

Zep acidic toilet bowl cleaner is one of the most effective chemical drain cleaner for removing limescale buildup. Check more about and as well as reviews here on Amazon.

How to Remove Calcium Buildup from a Toilet

For this job you will need the following:

  • White vinegar
  • Baking soda
  • Plunger/heavy cloth
  • Toilet brush
  • Allen wrench

When you have assembled together all the necessary items, proceed as follows:

1. Turn off Water to the Toilet

  • Look for a knob on the wall at the back of the toilet connected to a flexible water supply hose. That is the toilet’s shut off valve.
  • To turn off water to the toilet, turn the knob all the way clockwise. If you have a push/pull shut off valve pull the knob.
  • Flush the toilet and hold the handle down to remove as much water as possible.

2. Drain the Toilet Bowl

Toilet bowls are able to keep water at the bottom due to the design of the S-trap. This is the n-shaped part at the toilet which also makes suction/siphoning possible.

The water helps to create a barrier preventing sewer gases from coming up through the drain. P-traps also trap potential toilet clogs.

Since most of the limescale is deposited at the bottom of the bowl and you want the vinegar to work directly on it by dissolving it, you should first drain the bowl completely.

Use a toilet plunger to force as much water as possible down the drain. You can also soak up the water using a cloth. Be sure to have some nylon gloves for this.

3. Pour the Vinegar in the Bowl

  • Pour 2 cups of vinegar inside the toilet bowl and let it sit for about an hour.
  • Use a toilet brush to swish it around the bowl from time to time.

If you toilet has a siphon jet at the bottom of the bowl, the vinegar will as well dissolve the calcium clogging it and hence your toilet will flush better moving forward.

As you wait for the vinegar to dissolve the limescale in the toilet bowl, focus on removing the calcium deposits clogging your toilet bowl rim holes.

  • Start by boiling 1 cup of vinegar. If hot water can dissolve gunk better than cold water, it is the same principle with vinegar.
  • Remove the toilet tank lid and place it away in a safe place where it cannot fall off and break.
  • Look for a large cylindrical tube inside that tank. That is called an overflow tube. The overflow tube is connected to the flush valve, which is the opening at the bottom of the tank through which water enters the bowl.
  • Pour the vinegar slowly inside the overflow tube.

The vinegar will collect inside the bowl rim where it will dissolve the calcium deposits thereby opening up the holes. Let it sit there for a while as well.

4. Scrub the Toilet Bowl

  • After the 1 hour, slowly pour a cup of baking soda in the bowl. Since baking soda is an alkali, it will react with the vinegar (an acid) which will help to break down the calcium build up even more.
  • Baking soda is also a fantastic cleaning agent which apart from making surfaces shiny it deodorizes as well.
  • Use a toilet brush to mix the baking soda and vinegar while swishing the solution inside the bowl to target all the limescale.
  • Keep doing this for about 15 minutes.
  • Use the brush to aggressively scrub the toilet bowl targeting all the calcium build up until you remove it completely.
  • If the brush doesn’t seem to be doing a good job, put it down and get some non-scratch pads. Put on some nylon gloves and get down to scrubbing.
  • Do not forget to scrub underneath the toilet bowl rim. You will be surprised at the amount of limescale buildup there.

With the bowl sparkling clean, you will then need to make sure that the rim holes are fully opened.

  • Look for a small L-shaped Allen wrench and use it to poke through each of the toilet bowl rim hole
  • When that is done, turn on the water shut off valve and let the tank fill with water.
  • Flush it several times to check if all the limescale build is gone.
  • Before putting the tank cover back, squirt some dish soap inside the overflow tube. This will help to further clean the rim jets and it is something that you should actually do often.

I know some people use toilet tank tablets to prevent hard water stains in toilets but I do not recommend them. These tabs will accelerate the deterioration of rubber toilet tank parts like flappers and washers, resulting in leaks.

You can also clean the inside of your toilet tank if it has calcium and iron stains as well. For more information on how to clean a toilet tank check out this post.

As I had stated earlier, installing a water softener is the only permanent way of preventing calcium build up in toilets and other fixtures. Otherwise you will need to thoroughly clean them every now and then to prevent staining.

Leave a Comment