Filters can be a good place for bacteria to grow because there is plenty of water present, filters are dark and warm, and bacteria can feed on the organics present. While most of these bacteria do not pose a health hazard, they can cause problems for drinking water and filters.
About 25% of the largest municipal water supplies in the U.S. use chloramines instead of chlorine disinfection because it is more stable in water, allowing for disinfection over longer distances.
If excessive amounts are used or high concentrations reside in pipes and plumbing, chlorine can impart an undesirable taste and odor in your drinking water and other beverages. It can also contribute to foodservice equipment problems such as pitting and corrosion.