The water that ends up in our plumbing system comes from a source such as a river, lake, reservoir, or underground aquifer. The local water company then “treats” it to make it potable.
Depending on the water company and actual circumstances, it does this in a number of ways. But the following process is typical:
Flocculation: chemicals are added to the water to cause dissolved particles and dirt to combine into “floc.”
Sedimentation: the floc is heavy and settles to the bottom of the treatment tanks.
Filtration: the clear water at the top of the tank is passed through gravel, sand, and charcoal filters to remove remaining suspended particles. These include parasites, dust, viruses, bacteria, and chemicals.
Disinfection: chlorine is added. This kills remaining germs, viruses, bacteria and parasites. Some comp[anies also use ultraviolet radiation for the same purpose
Fluoridation: most municipalities add fluoride to help prevent tooth decay
The water is then delivered to your home with added chlorine in order to prevent infection en route.