Homeowners may choose to install a water filter in order to get rid of impurities in their tap water, or use a jug-style water filter in their refrigerator. On occasion, small white particles may be seen floating in filtered water. Finding white particles in filtered water can have a number of different causes.
The most common cause of white particles floating in filtered water is mineral deposits. Many locations across North America have hard water, which just means that there is a higher amount of dissolved minerals in the water. These flecks don't usually just appear in filtered water, and are usually flakes of deposits that have built up inside of the filter.
Not all filters remove dissolved minerals, which can later turn into white floating particles. One example of a water filter that does not remove dissolved minerals is an activated carbon filter. This type of filter is used in some home water filtration systems as well as fish tanks. The filter works by bonding to carbon present in the water, but there is no carbon in dissolved minerals so they can pass through it.
Freezing filtered water can cause dissolved minerals to separate from the water and precipitate, which means that they turn into solids. The extreme temperature change is what causes this process. This commonly happens when bottled water, which is a type of filtered water, is allowed to freeze. In order to prevent white particles in filtered water, don't allow it to freeze.
White flecks in filtered water are non-toxic and do not usually affect the taste of the water. However, frequent cleaning of the filter and associated plumbing with a scrub brush and a calcium, lime and rust-removing solvent can remove any mineral deposits before they can flake off into your filtered water.