How to Prevent Limescale Buildup in Your Home

Limescale is a hazard that a majority of Americans deal with in their homes. In fact, 85% of American households use water that causes limescale buildup due to its high mineral content. The issues caused by these minerals can be costly, unpleasant, and irritating, but they can be dealt with by eliminating the source of limescale. Below you can find information about limescale, what causes it, how to prevent it, and how to remove it from locations in your home.

What is limescale?

Limescale is a hard, chalky deposit of minerals left behind by hard water as it passes through plumbing systems and appliances. The most common and abundant minerals in hard water are calcium and magnesium carbonate. The harder the water, the more severe and costly scaling can be in pipes, appliances, and other plumbing components. Limescale is particularly hazardous because it can build up in any type of pipe. Iron, copper, and galvanized steel are the most susceptible to scaling. PEX, PVC, and CPVC, on the other hand, are more immune to limescale, but they can still experience clogs and buildup from extremely hard water.

What causes limescale in appliances?

Appliances scale when they contact water that is high in dissolved minerals like calcium and magnesium, known as hard water. When water evaporates, it leaves behind residue that vaporizes at a higher temperature than water. When hard water vaporizes, the mineral content is left behind and forms a scaly buildup. As a result, hot water applications, such as dishwashers, water heaters, pipes, and washing machines, are more susceptible to limescale than others, but any plumbing, fixture, or appliance that contacts hard water can experience scaling. Once the initial layer of limescale builds up inside a pipe or appliance, it accumulates on itself to further the problem.

Hard water is a problem in both municipal water supplies and well water. In fact, around 85% of American household water supplies contain high levels of water hardness. Calcium and magnesium are still safe to consume at these levels. Consequently, the EPA does not regulate these levels of water hardness in city-treated water. Because hard water is safe for human consumption, many homeowners ignore the problems hard water creates until the damage is costly.

What are the signs of limescale buildup?

Limescale buildup itself is a solid, chalky, and white substance that is fairly easy to spot in appliances that come into contact with water. However, signs of hard water that can lead to scaling can alert you of potential scaling before it becomes severe. These symptoms include:

  • Dry or itchy skin
  • Soap scum buildup in shower
  • Spots on dishes and glassware
  • Dry, filmy hair
  • Metallic taste
  • Little soap lather
  • Fading color in clothes

Water that contains substantial calcium and magnesium content struggles to break down soap more than soft water. If you notice soap scum residue in multiple different applications, such as dishes and clothing, hard water is likely the cause.

Certain regions of the United States are more prone to hard water in water supplies than others. The regions with the highest water hardness are the Midwest, Arizona, Utah, western Texas, and Florida. The regions with the lowest water hardness are the southeastern states (excluding Florida), the New England states, and Oregon. All water, regardless of supply, contains at least trace amounts of calcium and magnesium.

What problems does limescale buildup cause?

Limescale buildup wreaks havoc on the plumbing and appliances in a home. Not only is it unsightly, but it also causes the following problems.

  • Decreases water pressure by clogging pipes
  • Significantly shortens the lifespan of water-using appliances
  • Creates crust that can destroy heating elements
  • Reduce appliance efficiency
  • Force appliances to use more energy and water than under normal operation
  • Increases the cost of your water and electricity bill
  • Increases the environmental impact of appliances
  • Require appliances to be repaired and replaced more often

Because limescale can build back after being removed from plumbing systems and appliances, fixing the underlying problem of limescale is less expensive than dealing with the problems hard water causes.

While limescale buildup causes costly problems in a home’s plumbing and appliances, hard water presents problems beyond limescale and can cause physical irritation. Bathing with hard water creates dry, itchy skin that can be coated with a layer of soap scum. Magnesium and calcium can also reduce the volume and color of hair, causing it to look flat and lifeless.

Is hard water harmful to consume?

Hard water is not harmful to consume. In fact, magnesium and calcium are vital to health. The main source of magnesium and calcium should be food, not water intake. Softening your water, as a result, does not negatively affect your health. Rather, it prevents the dermatological effects of water-hardening minerals.

How to prevent limescale buildup in appliances

Limescale buildup is easy to prevent with a water softener, but it is much more difficult to resolve once it has become a problem. Limescale builds up in pipes, allowing it to overtake the entire plumbing system within a home. This means that water must be treated before it reaches a home’s plumbing system. Simply installing filters on each point of use will not resolve the limescale problem in a home.

Water softeners connect to a home’s main supply line, treating all water that enters the home’s plumbing system. A water softener utilizes a mineral tank, a control valve, and a brine tank to remove minerals from water. The mineral tank contains resin beads that exchange sodium ions for the hardness ions in the water. Once the resin beads become less efficient, the control valve initiates a regeneration cycle, which recharges the resin beads with a salt solution stored in the brine tank.

How to descale plumbing in the home

Removing limescale from pipes, fixtures, and appliances improves the efficiency of these systems, but it should not be treated like a permanent solution to the problem. To permanently resolve limescale issues, install a whole-home water softener at your home’s main supply lines, then remove the built-up limescale from your home’s plumbing, fixtures, and appliances. Many locations of limescale, such as in supply pipes, should only be removed by a licensed professional. Others, such as drain pipes, fixtures, and appliances, can be removed by a homeowner.

How to descale a drain

If limescale causes your drain to clog, you can break down the calcium in the drain pipe with hot water and a vinegar solution.

  1. Prepare ½ cup white vinegar and ½ cup baking soda.
  2. Pour both the white vinegar and baking soda down the drain.
  3. Plug the drain and wait 5 to 10 minutes.
  4. Pour boiling water down the drain. (Note: Boiling water should not be used if your sink is made of porcelain, as it may crack. Boiling water can melt the seals of PVC, CPVC, and PEX pipes, so avoid this step if your home uses these pipes.)
  5. If further descaling is needed, repeat these steps.

How to descale a water heater

Because they deal with hot water, water heaters can build up limescale quickly. One solution to scaling in water heaters outside of water softeners is a water heater filter. These remove sediment and scaling minerals from incoming water to protect your heater from damage. If you have solved your limescale problem with either a softener or a water heater filter, removing the buildup in your heater can permanently remove scaling from the tank.

  1. Create a solution of one-part white vinegar to one-part water.
  2. Shut off water to the heater.
  3. Open a faucet at the lowest point of your home. Allow it to release all water remaining in the pipes. Leave the faucet open while you clean the heater.
  4. Disconnect the heater from its power source.
  5. Use a hose to drain water from the heater.
  6. Remove the heating element if applicable.
  7. Scrub the inside of the heater with a brush dampened with the cleaning solution.
  8. Fill and drain the water heater to rinse it.
  9. If more descaling is needed, repeat these steps.

How to descale a dishwasher

Dishwashers, like water heaters, are very susceptible to limescale because they work with hot water. Limescale can be effectively removed from dishwashers by performing rinses with vinegar.

  1. Fill a dishwasher-safe container with one cup of distilled vinegar.
  2. Place the bowl on the top rack of the dishwasher.
  3. Start the longest, hottest cycle available on the dishwasher. Leave the rest of the dishwasher empty, and do not use any detergent or rinse aid.
  4. Once the cycle is complete, leave the dishwasher open to air out.
  5. If the vinegar smell is strong, consider running the dishwasher on a rinse cycle while empty.

How to descale a washing machine

Washing machines can easily fill with limescale after months or years of use with hard water. Like dishwashers, washing machines can be descaled by running a cycle with vinegar.

  1. Add a cup of distilled vinegar to the machine in place of detergent.
  2. Run the highest, hottest washing cycle available on your machine without clothes.
  3. Allow the machine to air out once the cycle is completed.

How to descale a faucet

A faucet is the easiest location in your home to descale, as it is easily accessible and viewable. Removing limescale from a faucet restores its proper shine, and it can help restore flow if the head is blocked.

  1. Soak a dish cloth in a solution of one-part distilled vinegar and one-part water.
  2. Wrap the faucet in the cloth and allow it to sit for as long as necessary.
  3. If limescale remains, you may opt to scrub it with a brush. Ensure that the brush you use does not scratch the exterior of your faucet.

Instead of a cloth, you may use a container that can be easily tied around the faucet, such as a plastic bag or balloon.

How to descale a toilet

Limescale will present itself as a brown crust in either the bowl or tank of a toilet. You can solve limescale issues in toilet bowls and tanks in the same way.

  1. Pour one cup of distilled vinegar into the toilet bowl or tank.
  2. Allow the vinegar to sit for 2 to 4 hours.
  3. Scrub the bowl or tank.
  4. Flush the toilet.
  5. Repeat this process until limescale is removed.

How to descale supply pipes

Unlike the other applications listed, supply pipes are not easily accessible because they only flow toward your appliances and fixtures. As a result, it is wise to contract a licensed professional to descale your supply pipes once a water softener is installed. If a water softener is installed and well maintained, removing limescale from the supply pipes should be a one-time ordeal.


Posted by John Woodard on April 01, 2023

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