Los Angeles County
Department of Public Health
Toxics Epidemiology Program
695 S. Vermont Avenue
South Tower, 14th Floor
Los Angeles, CA 90005

Phone: (213) 738-3220

Fax: (213) 252-4503

Email: tox@ph.lacounty.gov

Air Quality Management District

Childhood Lead Poisoning Prevention Program

Chronic Disease & Injury Prevention

Emergency Preparedness & Response Program

Environmental Health

Tobacco Control & Prevention Program

Air Resources Board

CA Department of Public Health

Cal/Environmental Protection Agency

California Poison Control System

Department of Toxic Substances Control

Division of Occupational Safety and Health

Environmental Health Investigations Branch

Agency for Toxic Substances and Disease Registry

Centers for Disease Control and Prevention

National Cancer Institute

National Institutes of Environmental Health Sciences

National Institutes of Health

National Pesticide Information Center

U.S. Environmental Protection Agency

U.S. Food and Drug Administration

In many supermarkets, bottled water now has its own aisle. There are large containers for home use, and smaller bottles for people on the go. There is water with fluoride and water without; there is ‘drinking water’, ‘spring water’ and ‘distilled water’. Why is so much space dedicated to these products? Because, when it comes to drinking water, more and more people are turning off their taps and resorting to bottled substitutes.

And people are paying a premium for these products: A liter bottle of spring water can cost a dollar or more. That’s a lot when you compare it to an equivalent amount of tap water. (In Los Angeles, a liter of water provided by the Department of Water and Power costs just pennies.)

For many, the extra cost is easy to justify. They argue that bottled water contains fewer contaminants and is safer to drink.

However, all water—regardless of its source—contains some contaminants. A mountain stream, for example, might contain significant amounts of animal waste; a remote underground spring may have high levels of radon (a radioactive material present in certain types of rocks and soil that can seep into ground water).

Water—particularly water drawn from sources near populated or industrialized areas—also frequently contains a variety of chemical impurities. Hazardous household waste like paint thinner or antifreeze that is improperly disposed of can migrate from disposal sites and contaminate sources of drinking water; pesticides applied to crops can be carried to lakes and streams after a heavy rain.

Some water impurities can cause significant health problems. High levels of the bacteria E. coli in water have been linked to gastrointestinal illness; high levels of arsenic have been tied to cancer.

To ensure that water is safe to drink, levels of potentially harmful contaminants are closely monitored. Strict water quality standards established by the U.S. Environmental Protection Agency limit the amount of various impurities in drinking water by setting “maximum contaminant levels”, or “MCLs”. Drinking water may not, for example, contain more than 0.002 mg/liter of mercury or more than 0.005 mg/liter of the chemical benzene. Currently, MCLs have been set for more than 80 different contaminants.

When water does not meet established standards, it is treated to reduce contaminant levels. The type of treatment methods used depends on the quality of the water and the specific contaminants that need to be removed. Filtration, for example, removes particulate material like sand and silt, while disinfection kills dangerous bacteria and viruses.

Contaminant levels can also be reduced through a process called blending. Blending involves mixing water drawn from different sources together. For example, by blending water that contains large amounts the chemical benzene with water that contains very little of it, the concentration of benzene is effectively lowered.

Although highly effective, treating and blending water are not intended to totally eliminate impurities from drinking water. The cost of reducing contaminant levels to zero from the already low levels demanded by the EPA would be prohibitively expensive. And, perhaps more importantly, would be unlikely to provide any additional health benefits.

To ensure that drinking water satisfies EPA standards, public water suppliers are required to routinely test their water. The Los Angeles Department of Water and Power, for example, monitors its water supply for over 170 contaminants. The water is sampled and tested every day of the year at various locations around the city.

Water suppliers must also provide an annual report to its customers. The report provides information on local drinking water quality, including the levels of various contaminants found in the water. Water quality reports can be obtained by contacting the supplier directly, or through the U.S. EPA’s website on Local Drinking Water Information.

The public water supply in the United States is better and safer than ever. And, by most reports, it’s expected to continue to improve. Each year hundreds of millions of dollars are being spent on source water protection and the development of improved water treatment technology. While tap water may not offer the variety that bottled water does, there’s very little evidence to suggest that it’s any less safe.

L.A. County Department of Public Works

Metropolitan Water District of Southern California

L.A. Regional Water Quality Control Board (California Environmental Protection Agency)

Drinking Water and Health: What you need to know (U.S. Environmental Protection Agency)

Ground Water & Drinking Water (U.S. Environmental Protection Agency)

Water On Tap: What You Need To Know (U.S. Environmental Protection Agency)

California Drinking Water (U.S. Environmental Protection Agency)

MedlinePlus for Drinking Water (U.S. National Library of Medicine and National Institutes of Health)

INORGANIC CONTAMINANTS

Antimony
Basic Information about Antimony in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Antimony (Centers for Disease Control and Prevention)
ToxFAQs™ for Antimony and Compounds (Agency for Toxic Substance and Disease Registry)

Arsenic
Arsenic in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Arsenic (Centers for Disease Control and Prevention)
ToxFAQs™ for Arsenic (Agency for Toxic Substances and Disease Registry)

Asbestos
Basic Information about Asbestos in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Asbestos (Centers for Disease Control and Prevention)
ToxFAQs™ for Asbestos (Agency for Toxic Substances and Disease Registry)

Barium
Basic Information about Barium in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Barium (Centers for Disease Control and Prevention)
ToxFAQs™ for Barium (Agency for Toxic Substances and Disease Registry)

Beryllium
Basic Information about Beryllium in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Beryllium (Centers for Disease Control and Prevention)
ToxFAQs™ for Beryllium (Agency for Toxic Substances and Disease Registry)

Cadmium
Basic Information about Cadmium in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Cadmium (Centers for Disease Control and Prevention)
ToxFAQs™ for Cadmium (Agency for Toxic Substance and Disease Registry)

Chromium
Basic Information about Chromium in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Chromium (Centers for Disease Control and Prevention)
ToxFAQs™ for Chromium (Agency for Toxic Substance and Disease Registry)

Copper
Public Health Statement for Copper (Centers for Disease Control and Prevention)
ToxFAQs™ for Copper (Agency for Toxic Substance and Disease Registry)

Cyanide
Basic Information about Cyanide in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Cyanide (Centers for Disease Control and Prevention)
ToxFAQs™ for Cyanide (Agency for Toxic Substance and Disease Registry)

Lead
Lead in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Lead (Centers for Disease Control and Prevention)
ToxFAQs™ for Lead (Agency for Toxic Substance and Disease Registry)

Mercury
Basic Facts about Mercury in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Mercury (Centers for Disease Control and Prevention)
ToxFAQs™ for Mercury (Agency for Toxic Substance and Disease Registry)

Nitrite
Basic Information about Nitrate in Drinking Water (U.S. Environmental Protection Agency)
Basic Information about Nitrite in Drinking Water (U.S. Environmental Protection Agency)

Selenium
Basic Information about Selenium in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Selenium (Centers for Disease Control and Prevention)
ToxFAQs™ for Selenium (Agency for Toxic Substance and Disease Registry)

Thallium
Basic Information about Thallium in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Thallium (Centers for Disease Control and Prevention)
ToxFAQs™ for Thallium (Agency for Toxic Substance and Disease Registry)

SYNTHETIC ORGANIC CONTAMINANTS

2,4-D
Basic Information about 2,4-D in Drinking Water (U.S. Environmental Protection Agency)

2,4,5-TP
Basic Information about 2,4,5-TP (SILVEX) in Drinking Water (U.S. Environmental Protection Agency)

Acrylamide
Basic Information about Acrylamide in Drinking Water (U.S. Environmental Protection Agency)

Alachlor
Basic Information about Alachlor in Drinking Water (U.S. Environmental Protection Agency)

Atrazine
Basic Information about Atrazine in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Atrazine (Centers for Disease Control and Prevention)
ToxFAQs™ for Atrazine (Agency for Toxic Substance and Disease Registry)

Benzo(a)pyrene
Basic Information about Benzo(a)pyrene in Drinking Water (U.S. Environmental Protection Agency)

Carbofuran
Basic Information about Carbofuran in Drinking Water (U.S. Environmental Protection Agency)

Chlordane
Basic Information about Chlordane in Drinking Water (U.S. Environmental Protection Agency)
Pulbic Health Statement for Chlordane (Centers for Disease Control and Prevention)
ToxFAQs™ for Chlordane (Agency for Toxic Substance and Disease Registry)

Dalapon
Basic Information about Dalapon in Drinking Water (U.S. Environmental Protection Agency)

Di(2-ethylhexyl) Adipate
Basic Information about Di(2-ethylhexyl) Adipate in Drinking Water (U.S. Environmental Protection Agency)

Di(2-ethylhexyl) Phthalate
Basic Information about Di(2-ethylhexyl) Phthalate in Drinking Water (U.S. Environmental Protection Agency)

1,2-Dibromo-3-chloropropane (DBCP)
Basic Information about 1,2-Dibromo-3-chloropropane in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for 1,2-Dibromo-3-chloropropane (Centers for Disease Control and Prevention)
ToxFAQs™ for 1,2-Dibromo-3-chloropropane (Agency for Toxic Substance and Disease Registry)

Dinoseb
Basic Information about Dinoseb in Drinking Water (U.S. Environmental Protection Agency)

Dioxin (2,3,7,8-TCDD)
Basic Information about Dioxin in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Chlorinated Dibenzo-p-dioxins (CDDs) (Centers for Disease Control and Prevention)
ToxFAQs™ for Chlorinated Dibenzo-p-dioxins (CDDs) (Agency for Toxic Substance and Disease Registry)

Diquat
Basic Information about Diquat in Drinking Water (U.S. Environmental Protection Agency)

Endothall
Basic Information about Endothall in Drinking Water (U.S. Environmental Protection Agency)

Endrin
Basic Information about Endrin in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Endrin (Centers for Disease Control and Prevention)
ToxFAQs™ for Endrin (Agency for Toxic Substance and Disease Registry)

Epichlorohydrin
Basic Information about Epichlorohydrin in Drinking Water (U.S. Environmental Protection Agency)

Ethylene Dibromide
Basic Information about Ethylene Dibromide in Drinking Water (U.S. Environmental Protection Agency)

Glyphosate
Basic Information about Glyphosate in Drinking Water (U.S. Environmental Protection Agency)

Heptachlor/Heptachlor Epoxide
Basic Information about Heptachlor in Drinking Water (U.S. Environmental Protection Agency)
Basic Information about Heptachlor Epoxide in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Heptachlor and Heptachlor Epoxide (Centers for Disease Control and Prevention)
ToxFAQs™ for Heptachlor and Heptachlor Epoxide (Agency for Toxic Substance and Disease Registry)

Hexachlorobenzene
Basic Information about Hexachlorobenzene in Drinking Water (U.S. Environmental Protection Agency)

Hexachlorocyclopentadiene
Basic Information about Hexachlorocyclopentadiene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Hexachlorocyclopentadiene (HCCPD) (Centers for Disease Control and Prevention)
ToxFAQs™ for Hexachlorocyclopentadiene (HCCPD) (Agency for Toxic Substance and Disease Registry)

Lindane
Basic Information about Lidane in Drinking Water (U.S. Environmental Protection Agency)

Methoxychlor
Basic Information about Methoxychlor in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Methoxychlor (Centers for Disease Control and Prevention)
ToxFAQs™ for Methoxychlor (Agency for Toxic Substance and Disease Registry)

Oxamyl
Basic Information about Oxamyl in Drinking Water (U.S. Environmental Protection Agency)

Pentachlorophenol
Basic Information about Pentachlorophenol in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Pentachlorophenol (Centers for Disease Control and Prevention)
ToxFAQs™ for Pentachlorophenol (Agency for Toxic Substance and Disease Registry)

Picloram
Basic Information about Picloram in Drinking Water (U.S. Environmental Protection Agency)

Polychlorinated biphenyls (PCBs)
Basic Information about Polychlorinated biphenyls in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Polychlorinated Biphenyls (PCBs) (Centers for Disease Control and Prevention)
ToxFAQs™ for Polychlorinated Biphenyls (PCBs) (Agency for Toxic Substance and Disease Registry)

Simazine
Basic Information about Simazine in Drinking Water (U.S. Environmental Protection Agency)

Toxaphene
Basic Information about Toxaphene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Toxaphene (Centers for Disease Control and Prevention)
ToxFAQs™ for Toxaphene (Agency for Toxic Substance and Disease Registry)

VOLATILE ORGANIC CONTAMINANTS

Benzene
Basic Information about Benzene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Benzene (Centers for Disease Control and Prevention)
ToxFAQs™ for Benzene (Agency for Toxic Substance and Disease Registry)

Carbon tetrachloride
Basic Information about Carbon tetrachloride in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Carbon Tetrachloride (Centers for Disease Control and Prevention)
ToxFAQs™ for Carbon Tetrachloride (Agency for Toxic Substance and Disease Registry)

Chlorobenzene
Basic Information about Chlorobenzene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Chlorobenzene (Centers for Disease Control and Prevention)
ToxFAQs™ for Chlorobenzene (Agency for Toxic Substance and Disease Registry)

Ortho-dichlorobenzene (o-DCB)
Basic Information about Ortho-dichlorobenzene in Drinking Water (U.S. Environmental Protection Agency)

Para-dichlorobenzene (p-DCB)
Basic Information about Para-dichlorobenzene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Dichlorobenzenes (Centers for Disease Control and Prevention)
ToxFAQs™ for Dichlorobenzenes (Agency for Toxic Substance and Disease Registry)

1,1-Dichloroethylene
Basic Information about 1,1-Dichloroethylene in Drinking Water (U.S. Environmental Protection Agency)

trans-1,2-Dichloroethylene
Basic Information about trans-1,2-Dichloroethylene in Drinking Water (U.S. Environmental Protection Agency)

Dichloromethane
Basic Information about Dichloromethane in Drinking Water (U.S. Environmental Protection Agency)

1,2-Dichloroethane
Basic Information about 1,2-dichloroethane in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for 1,2-Dichloroethane (Centers for Disease Control and Prevention)
ToxFAQs™ for 1,2-Dichloroethane (Agency for Toxic Substance and Disease Registry)

1,2-Dichloropropane
Basic Information about 1,2-Dichloropropane in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for 1,2-Dichloropropane (Centers for Disease Control and Prevention)
ToxFAQs™ for 1,2-Dichloropropane (Agency for Toxic Substance and Disease Registry)

Ethylbenzene
Basic Information about Ethylbenzene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Ethylbenzene (Centers for Disease Control and Prevention)
ToxFAQs™ for Ethylbenzene (Agency for Toxic Substance and Disease Registry)

Styrene
Basic Information about Styrene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Styrene (Centers for Disease Control and Prevention)
ToxFAQs™ for Styrene (Agency for Toxic Substance and Disease Registry)

Tetrachloroethylene (PERC)
Basic Information about Tetrachloroethylene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Tetrachloroethylene (Centers for Disease Control and Prevention)
ToxFAQs™for Tetrachloroethylene (PERC) (Agency for Toxic Substance and Disease Registry)

1,2,4-Trichlorobenzene
Basic Information about 1,2,4-Trichlorobenzene in Drinking Water (U.S. Environmental Protection Agency)

1,1,1-Trichloroethane
Basic Information about 1,1,1-Trichloroethane in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for 1,1,1-Trichloroethane (Centers for Disease Control and Prevention)
ToxFAQs™ for 1,1,1-Trichloroethane (Agency for Toxic Substance and Disease Registry)

1,1,2-Trichloroethane
Basic Information about 1,1,2-Trichloroethane in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for 1,1,2-Trichloroethane (Centers for Disease Control and Prevention)
http://www.atsdr.cdc.gov/tfacts148.html (Agency for Toxic Substance and Disease Registry)

Trichloroethylene
Basic Information about Trichloroehtylene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Trichloroethylene (Centers for Disease Control and Prevention)
ToxFAQs™ for Trichloroethylene (TCE) (Agency for Toxic Substance and Disease Registry)

Toluene
Basic Information about Toluene in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Toluene (Centers for Disease Control and Prevention)
ToxFAQs™ for Toluene (Agency for Toxic Substance and Disease Registry)

Vinyl chloride
Basic Information about Vinyl Chloride in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Vinyl Chloride (Centers for Disease Control and Prevention)
ToxFAQs™ for Vinyl Chloride (Agency for Toxic Substance and Disease Registry)

Xylenes
Basic Information about Xylenes in Drinking Water (U.S. Environmental Protection Agency)
Public Health Statement for Xylene (Centers for Disease Control and Prevention)
ToxFAQs™ for Xylene (Agency for Toxic Substance and Disease Registry)