Substances Expected to be in Drinking Water
T he sources of drinking water (both tap water and bottled water) include
rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels
over the surface of the land or through the ground, it dissolves naturally
occurring minerals and, in some cases, radioactive material, and can pick up
substances resulting from the presence of animals or from human activity.
Substances that may be present in source water include:
Microbial Contaminants, such as viruses and bacteria, which may come from
sewage treatment plants, septic systems, agricultural livestock operations, and
wildlife;
Pesticides and Herbicides, which may come from a variety of sources such as
agriculture, urban stormwater runoff, and residential uses;
Inorganic Contaminants, such as salts and metals, which can be
naturally-occurring or result from urban stormwater runoff, industrial or domestic
wastewater discharges, oil and gas production, mining, or farming;
Organic Chemical Contaminants, including synthetic and volatile organic
chemicals, which are byproducts of industrial processes and petroleum
production, and can also come from gas stations, urban stormwater runoff, and
septic systems;
Radioactive Contaminants, which can be naturally-occurring or be the result
of oil and gas production and mining activities.
In order to ensure that tap water is safe to drink, EPA prescribes regulations
that limit the amount of certain contaminants in water provided by public water
systems. The Food and Drug Administration (FDA) regulations establish limits
for contaminants in bottled water, which must provide the same protection for
public health. Drinking water, including bottled water, may reasonably be
expected to contain at least small amounts of some contaminants. The presence
of contaminants does not necessarily indicate that water poses a health risk. More
information about contaminants and potential health effects can be obtained by
calling the U.S. EPA’s Safe Drinking Water Hotline (1-800-426-4791).
