Physical Characteristics. The pertinent physical characteristics of water
supplies include temperature, turbidity, color, taste, and odor. Of these, only turbidity is
regulated. Information on the physical properties of water can be found in pars. 2.1.2
Chemical Characteristics. Chemical contaminants in water fall into two
broad categories: organic and inorganic. In general, organic chemicals have a carbon-
based structure while inorganic chemicals do not. More than 1,000 organic chemicals
have been found in drinking water, and the list is growing. The more common inorganic
characteristics include pH, alkalinity, hardness, calcium, stability, iron, manganese,
dissolved oxygen, and fluoride. More information on chemical characteristics, including
the regulatory standards for drinking water, can be found in pars. 2.1.2 and 2.1.3.
Biological Characteristics. Plants and animals, both living and dead,
contribute to the biological characteristics of water. Included in this category are algae,
bacteria, viruses, and protozoa such as Giardia and Cryptosporidium. However, not all
forms are microscopic. Some large aquatic plants (macrophytes) found in lakes and
reservoirs can be of concern as well. More information on the biological characteristics
of water, including common control measures, can be found in pars. 2.1.2, 2.1.3, 2.1.5,
humans. Some water supplies have relatively high levels of natural radioactivity.
Other potential sources of radionuclide contamination are industrial and medical
standards, can be found in pars. 2.1.2 and 2.1.3.