Hard water scale is buildup on a surface due to the minerals found in water. Usually the minerals that cause hard water scale are calcium and magnesium. The scale appears as a white film on any surface that comes into constant contact with hard water, such as faucets and shower doors. Hard water scale, also called lime scale, can be removed using commercial cleaners or vinegar. A person can also install a water softener, which removes minerals from the water before it travels through pipes.
If a home or other building has hard water, lime scale will build up anywhere water is commonly used. Hard water scale can accumulate in washing machines or coffee makers, for example. It will also coat the glass surface of a shower door or the metal surface of a faucet. Scale can also appear on tiled surfaces, fiberglass bathtubs and sinks, and on chrome. Hard water scale can be easy to clean if removed often. The longer the scale sits on a surface, the more difficult it is to remove.
Commercial products are available to clean up hard water scale. The products usually contain ingredients that sequester, or bind with, the minerals in the scale, which make it easier to remove the scale and also prevent a film of soap from building up. Acids such as sulphuric acid or phosphoric acid are commonly used in commercially available cleaners to break down and bind with the hard water scale.
Hard water scale can also be removed using a milder acid, such as distilled white vinegar or even citrus juice. For the acid to effectively remove the scale, it must remain in contact with it for a period of time. A person should spray a mixture of vinegar and water on a surface coated with lime scale and let the acid soak into the scale for about an hour for best results.
As scale can build up in water pipes, a person may wish to remove it from the pipes to prevent clogs and other damage to appliances. To remove scale from a washing machine or a dishwasher, a person should run an empty load, using 1 cup (250 grams) of vinegar in place of detergent. Coffee makers usually have specific instructions for using white vinegar to remove scale from inside the machine and in the carafe. Some people may pour a small amount of vinegar down a sink drain, followed by running cold water, to prevent clogs.