Substances That Could Be in Water
To ensure that tap water is safe to drink, the U.S. EPA prescribes
regulations limiting the amount of certain contaminants in
water provided by public water systems. U.S. Food and Drug
Administration 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 these contaminants does not necessarily indicate
that the water poses a health risk.
The 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, in some cases, radioactive
material, and substances resulting from the presence of animals
or from human activity. Substances that may be present in source
Microbial Contaminants, such as viruses and bacteria, which may
come from sewage treatment plants, septic systems, agricultural
livestock operations, or wildlife; Inorganic Contaminants, such as
salts and metals, which can be naturally occurring or may result
from urban storm-water runoff, industrial or domestic wastewater
discharges, oil and gas production, mining, or farming; Pesticides
and Herbicides, which may come from a variety of sources
such as agriculture, urban storm-water runoff, and residential
uses; Organic Chemical Contaminants, including synthetic and
volatile organic chemicals, which are by-products of industrial
processes and petroleum production and may also come from gas
stations, urban storm-water runoff, and septic systems; Radioactive
Contaminants, which can be naturally occurring or may be the
result of oil and gas production and mining activities.
For more information about contaminants and potential health
effects, call the U.S. EPA’s Safe Drinking Water Hotline at (800)