What is Limescale?
One of the most prevalent substances that builds up in and around plumbing fixtures is limescale. Whether you are familiar with the term or not, you’ve undoubtedly encountered it in your home at one time or another. To best explain how limescale is formed, we must first understand water hardness.

Water Hardness
Water is considered “hard” when it contains a substantial concentration of calcium and magnesium ions. Hardness can be temporary or permanent, depending on the different classifications of ions contained in the water. The dissolution of calcium and magnesium bicarbonates in water results in temporary hardness, as the bicarbonates can be removed from the water by boiling it. On the other hand, if the water contains calcium and magnesium sulfates, these cannot be removed from the water and are thus considered “permanent”.
Limescale Formation
Since hard water contains a high concentration of dissolved minerals, it leaves behind calcium carbonate deposits when it evaporates. This substance, known as limescale, builds up on surfaces that frequently come in contact with hard water. When additional compounds like soaps interact with hard water in your plumbing, it causes a reaction that produces insoluble stearate salts, commonly known as “soap scum.”
How to Remove Limescale
There are a few products on the market that are successful in removing limescale from showers, bathrooms, sinks, and other plumbing fixtures susceptible to the buildup. These cleaners have a large concentration of citric, lactic, formic, or hydrochloric acids. The acids react with the limescale to form soluble metal salts that are easy to wipe away from the affected surface.
How to Prevent Limescale
If “hard” water produces limescale, shouldn’t “softening” the water prevent it? It sure does! Many homes with hard water have water softening systems installed that utilize salts to break down the minerals present in the water. If you have hard water and a softening system but still notice limescale buildup, it’s best to call a professional to determine whether the system is simply not getting enough salt treatments or if it is a sign of a larger problem.
Michael Runk Plumbing and Heating is an Eldersburg Master Plumber dedicated to keeping your home safe from the damage and health issues that faulty plumbing can cause. Contact us to learn more about dealing with limescale or to schedule a service appointment today!