What Is the White Deposit in My Shower?

Limescale

• Calcium carbonate, better known as limescale, is a white mineral deposit that builds up on surfaces that are frequently exposed to hard water. Limescale is so solid that any cleaning substance abrasive enough to remove it is also prone to damaging the underlying finish. Because limescale dissolves in acid, the best approach to getting rid of it is gentle scrubbing with a sponge or rag soaked in lemon juice or vinegar. For stubborn deposits, wrap fixtures in a lemon or vinegar-soaked rag and leave them for an hour before scrubbing.

Soap Scum

• Hard water also causes problems by combining with soap molecules to form a water-insoluble scum that sticks to glass, tiles and metal fixtures. This soap scum buildup causes a dull, whitish layer to form. It is difficult to remove by scrubbing alone; as with limescale, the trick is to soak the scum with something to chemically weaken it first. Good choices include a paste of baking soda and white vinegar or 2 to 4 tablespoons of trisodium phosphate dissolved in a gallon of water. Let the cleaner stand until the soap scum dissolves and rinse with clean water.

Mildew

• Some types of fungi that grow in the damp conditions of your shower produce a patchy, white growth known as mildew. Mildew requires food, heat and moisture to grow. Dirty shower surfaces provide enough nutrients for mildew to take hold in a warm, moist bathroom. Shower curtains are particularly prone to mildew growth. To remove mildew, scrub shower surfaces with 1/2 cup of bleach mixed with a gallon of water. Rinse with clean water and wipe dry.

Prevention

• Add a few simple steps to your daily routine to prevent limescale, soap scum and mildew buildup in your shower. Keep moisture levels as low as possible in the bathroom. If you have an exhaust fan, use it. Minimize both moisture and hard water buildup by wiping the inside of the shower with a towel after the last person is finished showering. Consider using a daily shower cleaner containing a chelating agent to prevent minerals from adhering to the walls and fixtures. Such cleaners usually contain a mildew preventer, as well.