National Primary Drinking Water Standards


                                                                       1
         United States
         Environmental Protection
         Agency
Office of Water
(4606)
EPA816-F-01-007  -
March 2001
www.epa.gov/safewater
&EPA  National Primary Drinking Water Standards
Contaminant
MICROORGANISMS
Ciyptosporidiam
Giardia lamblia
Heterotrophic plate count
(HPC)
Legionella
Total Conforms (including
fecal coliform and E. coli)
Turbidity
Viruses (enteric)
MCLG1
(mg/L)2
MCL or TT1
(mg/L)2
Potential health effects from exposure above the MCL
Common sources of contaminant in drinking water

as of 01/01/02:
zero
zero
n/a
zero
zero
n/a
zero
as of 01/0 1/02:
TT3
TT3
TT3
-TT3
5.0%"
TT3
TT3
Gastrointestinal illness (e.g., diarrhea, vomiting,
cramps)
Gastrointestinal illness (e.g., diarrhea, vomiting,
cramps)
HPC has no health effects; it is an analytic method
used to measure the variety of bacteria that are
common in water. The lower the concentration of
bacteria in drinking water, the better maintained tie
water system is.
Legionnaire's Disease, a type of pneumonia
Not a health threat in itself; it is used to indicate
whether other potentially harmful bacteria may be
present5
Turbidity is a measure of the cloudiness of water. It is
used to indicate water quality and filtration
effectiveness (e.g., whether disease-causing organisms
are present). Higher turbidity levels are often
associated with higher levels of disease-causing
microorganisms such as viruses, parasites and some
bacteria. These organisms can cause symptoms such
as nausea, cramps, diarrhea, and associated headaches.
Gastrointestinal illness (e.g., diarrhea, vomiting,
cramps)
Human and fecal animal waste
Human and animal fecal waste
HPC measures a range of bacteria that are naturally
present in the environment
Found naturally in water; multiplies in heating
systems
Total coliforms are naturally present in the
environment; fecal coliforms and E. coli come from
human and animal fecal waste.
Soil runoff
Human and animal fecal waste
DISINFECTANTS AND DISINFECTION B YPRODUCTS
Bromate
Chloramines (as CIJ
Chlorine (as C12)
Chlorine dioxide (as CIO,)
Chlorite
Haloacetic acids (HAA5)
Total Trihalomethanes
(TTHMs)
as of 01/01/02:
zero
as of 01/01/02:
MRDLG=4'
as of 01/01/02:
MRDLG=4'
as of 01/01/02:
MRDLG=0.8'
as of 01/01/02:
0.8
as of 01/01/02:
n/a6
none7
as of 01/01/02:
n/a6
as of 01/01/02:
0.010
as of 01/01/02:
MRDL=4.0'
as of 01/01/02:.
MRDL=4.0'
as of 01/01/02:
MRDL=0.8'
as of 01/01/02:
1.0
as of 01/01/02:
0.060
0.10
as of 01/01/02:
0.080
Increased risk of cancer
Eye/nose irritation; stomach discomfort, anemia
Eye/nose irritation; stomach discomfort
Anemia; infants & young children: nervous system
effects
Anemia; infants & young children: nervous system
effects
Increased risk of cancer
Liver, kidney or central nervous system problems;
increased risk of cancer
Byproduct of drinking water disinfection
Water additive used to control microbes
Water additive used to control microbes
Water additive used to control microbes
Byproduct of drinking water disinfection
Byproduct of drinking water disinfection
Byproduct of drinking water disinfection
INORGANIC CHEMICALS . .
Antimony -
Arsenic
Asbestos
(fibers >10 micrometers)
Barium
0.006
none7
7 million
fibers per
Liter (MFL)
.2
0.006
0.05
7 MFL
2
Increase in blood cholesterol; decrease in blood sugar
Skin damage; circulatory system problems; increased
risk of cancer
Increased risk of developing benign intestinal polyps
Increase in blood pressure
Discharge from petroleum refineries; fire retardants;
ceramics; electronics; solder
Erosion of natural deposits; runoff from orchards;
runoff from glass and electronics production wastes
Decay of asbestos cement in water mains; erosion of
natural deposits
Discharge of drilling wastes; discharge from metal
refineries; erosion of natural deposits

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Contaminant
Bejyllium
Cadmium
Chromium (total)
Copper
Cyanide
(as free cyanide)
Fluoride
Lead
Mercury (inorganic)
Nitrate
(measured as Nitrogen)
Nitrite
(measured as Nitrogen)
Selenium
Thallium
MCLG1
(mg/L)J
0.004
0.005
0.1
1.3
0.2
4.0
zero
0.002
10
1
0.05
0.0005
MCLorTT1
(mg/L)z
0.004
0.005
0.1
TT8;
Action Level=
1.3
0.2
4.0
TT8;
Action Level=
0.015
0.002
10
1
0.05
0.002
Potential health effects from exposure above the MCL
Intestinal lesions
Kidney damage
Allergic dermatitis
Short term exposure: Gastrointestinal distress
Long term exposure: Liver or kidney damage
People with Wilson's Disease should consult their
personal doctor if the amount of copper in their water
exceeds the action level
Nerve damage or thyroid problems
Bone disease (pain and tenderness of the bones);
Children may get mottled teeth
Infants and children: Delays in physical or mental
development; children could show slight deficits in
attention span and learning abilities
Adults: Kidney problems; high blood pressure
Kidney damage
Infants below the age of six months who drink water
containing nitrate in excess of the MCL could become
seriously ill and, if untreated, may die. Symptoms
include shortness of breath and blue-baby syndrome.
Infants below the age of six months who drink water
containing nitrite in excess of the MCL could become
seriously ill and, if untreated, may die. Symptoms
include shortness of breath and blue-baby syndrome.
Hair or fingernail loss; numbness in fingers or toes;
circulatory problems
Hair loss; changes in blood; kidney, intestine, or liver
problems
Common sources of contaminant in drinking water
Discharge from metal refineries and coal-burning
factories; discharge from electrical, aerospace, and
defense industries
Corrosion of galvanized pipes; erosion of natural
deposits; discharge from metal refineries; runoff from
waste batteries and paints
Discharge from steel and pulp mills; erosion of
natural deposits
Corrosion of household plumbing systems; erosion of
natural deposits
Discharge from steel/metal factories; discharge from
plastic and fertilizer factories
Water additive which promotes strong teeth; erosion
of natural deposits; discharge from fertilizer and
aluminum factories
Corrosion of household plumbing systems; erosion of
natural deposits
Erosion of natural deposits; discharge from refineries
and factories; runoff from landfills and croplands
Runoff from fertilizer use; leaching from septic tanks,
sewage; erosion of natural deposits
Runoff from fertilizer use; leaching from septic tanks,
sewage; erosion of natural deposits
Discharge from petroleum refineries; erosion of
natural deposits; discharge from mines
Leaching from ore-processing sites; discharge from
electronics, glass, and drug factories
ORGANIC CUBJICUS • :
Acrylamide
Alachlor
Alraanc
Benzene
Benzo(a)pyrene (PAHs)
GuboJbtan
Caibon tctraehloride
Chlordane
Chlorobenzene
2,4-D
Dalapon
I,2-Dibr0mo-3-
dttoropropmne (DBCP)
o-Dichlorobenzcnc
zero
zero
0.003
zero
zero
0.04
zero
zero
O.I
0.07
0.2
zero
0.6
TT3
0.002
0.003
0.005
0.0002
0.04
0.005
0.002
0.1
0.07
0.2
0.0002
0.6
Nervous system or blood problems; increased risk of
cancer
Eye, liver, kidney or spleen problems; anemia;
increased risk of cancer
Cardiovascular system or reproductive problems
Anemia; decrease in blood platelets; increased risk of
cancer
Reproductive difficulties; increased risk of cancer
Problems with blood, nervous system, or reproductive
system
Liver problems; increased risk of cancer
Liver or nervous system problems; increased risk of
cancer
Liver or kidney problems
Kidney, liver, or adrenal gland problems
Minor kidney changes
Reproductive difficulties; increased risk of cancer
Liver, kidney, or circulatory system problems
Added to water during sewage/wastewater treatment
Runoff from herbicide used on row crops
Runoff from herbicide used on row crops
Discharge from factories; leaching from gas storage
tanks and landfills
Leaching from linings of water storage tanks and
distribution lines
Leaching of soil rumigant used on rice and alfalfa
Discharge from chemical plants and other industrial
activities
Residue of banned termiticide
Discharge from chemical and agricultural chemical
factories
Runoff from herbicide used on row crops
Runoff from herbicide used on rights of way
Runoff/leaching from soil fumigant used on
soybeans, cotton, pineapples, and orchards
Discharge from industrial chemical factories

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Contaminant
p-Dichlorobenzene
1 ,2-Dichloroethane
1 , 1 -Dichloroethylene
cis- 1 ,2-DichIoroethyIene
trans- 1,2-
Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
Di(2-ethylhexyl) adipate
Di(2-ethylhexyl) phthalate
Dinoseb
Dioxin (2,3,7,8-TCDD)
Diquat
Endothall
Endrin
Epichlorohydrin
Ethylbenzene
Ethylene dibromide
Glyphosate
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hcxachlorocyclopcntadicnc
Lindane
Methoxychlor
Oxamyl (Vydate)
Polychiorinated biphenyls
(PCBs)
Pentachlorophenol
Picloram
Simazine
Styrene
Tetrachloroethylene
Toluene
Toxaphene
2,4,5-TP (Silvex)
1 ,2,4-TrichIorobenzene
1,1, 1-Trichloroethane
1,1,2-TrichIoroethane
MCLG1
(mg/L)2
0.075
zero
0.007
0.07
0.1
zero
zero
0.4
zero
0.007
zero
._. 0.02 	 	
0.1
0.002
zero
0.7
zero
0.7
zero
zero
zero
0.05
0.0002
0.04
0.2
zero
zero
0.5
0.004
0.1
zero
1
zero
0.05
0.07
0.20
0.003
MCLorTT1
(mg/L)2
0.075
0.005
0.007
0.07
0.1
0.005
0.005
0.4
0.006
0.007
0.00000003
. . ...0.02....
0.1
0.002
XT'
0.7
0.0.0005
0.7
0.0004
0.0002
0.001
0.05
0.0002
0.04
0.2
0.0005
0.001
0.5
0.004
0.1
0.005
1
0.003
0.05
0.07
0.2
0.005
Potential health effects from exposure above the MCL
Anemia; liver, kidney or spleen damage; changes in
blood : ' •'_
Increased risk of cancer
Liver problems
Liver problems
Liver problems
Liver problems; increased risk of cancer
Increased risk of cancer
General toxic effects or reproductive difficulties
Reproductive difficulties; liver problems; increased
risk of cancer
Reproductive difficulties
Reproductive difficulties; increased risk of cancer
Cataracts .._ ,, 	 	 .. .... ,
Stomach and intestinal problems
Liver problems
Increased cancer risk, and over a long period of time,
stomach problems
Liver or kidneys problems
Problems with liver, stomach, reproductive system, or
kidneys; increased risk of cancer
Kidney problems; reproductive difficulties
Liver damage; increased risk of cancer
Liver damage; increased risk of cancer
Liver or kidney problems; reproductive difficulties;
increased risk of cancer
Kidney or stomach problems
Liver or kidney problems
Reproductive difficulties
Slight nervous system effects
Skin changes; thymus gland problems; immune
deficiencies; reproductive or nervous system
difficulties; increased risk of cancer
Liver or kidney problems; increased cancer risk
Liver problems
Problems with blood
Liver, kidney, or circulatory system problems
Liver problems; increased risk of cancer
Nervous system, kidney, or liver problems
Kidney, liver, or thyroid problems; increased risk of
cancer
Liver problems
Changes in adrenal glands
Liver, nervous system, or circulatory problems
Liver, kidney, or immune system problems
Common sources of contaminant in drinking water
Discharge from industrial chemical factories
Discharge from industrial chemical factories
Discharge from industrial chemical factories
Discharge from industrial chemical factories
Discharge from industrial chemical factories
Discharge from drug and chemical factories
Discharge from industrial chemical factories
Discharge from chemical factories
Discharge from rubber and chemical factories
Runoff from herbicide used on soybeans and
vegetables
Emissions from waste incineration and other
combustion; discharge from chemical factories
Runoff from herbicide use 	
Runoff from herbicide use
Residue of banned insecticide
Discharge from industrial chemical factories; an
impurity of some water treatment chemicals
Discharge from petroleum refineries
Discharge from petroleum refineries
Runoff from herbicide use
Residue of banned termiticide
Breakdown of heptachlor
Discharge from metal refineries and agricultural
chemical factories
Discharge from chemical factories
Runoff/leaching from insecticide used on cattle,
lumber, gardens
Runofffleaching from insecticide used on fruits,
vegetables, alfalfa, livestock
Runoff/leaching from insecticide used on apples,
potatoes, and tomatoes
Runoff from landfills; discharge of waste chemicals
Discharge from wood preserving factories
Herbicide runoff
Herbicide runoff
Discharge from rubber and plastic factories; leaching
from landfills
Discharge from factories and dry cleaners
Discharge from petroleum factories
Runoff/leaching from insecticide used on cotton and
cattle
Residue of banned herbicide
Discharge from textile finishing factories
Discharge from metal degreasing sites and other
factories
Discharge from industrial chemical factories

-------
Contaminant
Trichtofocthylcne
Vinyl chloride
Xylencs (total)
MCLG1
(mg/L)1
zero
zero
10
MCLorTT1
(mg/L)z
0.005
0.002
10
Potential health effects from exposure above the MCL
Liver problems; increased risk of cancer
Increased risk of cancer
Nervous system damage
Common sources of contaminant nn drinking water
Discharge from metal degreasing sites and other
factories
Leaching from PVC pipes; discharge from plastic
factories
Discharge from petroleum factories; discharge from
chemical factories
RADIONTCLIDES
Alpha particles
Beta panicles and photon
emitters
Rtdium 226 and Radium
22S (combined)
none7
none7
none7
15 picocuries
per Liter
(pCi/L)
4 millirems
per year
(mrem/yr)
5pCi/L
Increased risk of cancer
Increased risk of cancer
Increased risk of cancer
Erosion of natural deposits of certain minerals that
are radioactive and may emit a form of radiation
known as alpha radiation
Decay of natural and man-made deposits of
certain minerals that are radioactive and may emit
forms of radiation known as photons and beta
radiation
Erosion of natural deposits
NOTES

I • Definitions
* Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow
for a margin of safety and are non-enforceable public health goals.
« Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the
best available treatment technology and taking cost into consideration. MCLs are enforceable standards.
• Maximum Residual Disinfectant Level Goal (MRDLG) - The level of a drinking water disinfectant below which there is no known or expected risk to health.
MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.
• Maximum Residual Disinfectant Level (MRDL) - The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a
disinfectant is necessary for control of microbial contaminants.
• Treatment Technique (TT) - A required process intended to reduce the level of a contaminant in drinking water.

2 - Units arc in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million (ppm).

3 » EPA's surface water treatment rules require systems using surface water or ground water under the direct influence of surface water to (1) disinfect their water, and (2) filter
their water or meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels:
• Cryptosporidium:(as of January 1,2002) 99% removal
* Giarttta lamblia: 99.9% removal/inactivation
• Viruses: 99.99% removal/inactivation
* ieglonella: No limit, but EPA believes that if Giardia and viruses are removed/inactivated, Legionella will also be controlled.
• Turbidity: At no time can turbidity (cloudiness of water) go above 5 nephelolometric turbidity units (NTU); systems that filter must ensure that the turbidity go no
higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples in any month. As of January 1, 2002, turbidity may never
exceed 1 NTU, and must not exceed 0.3 NTU in 95% of daily samples in any month.
* HPC: No more than 500 bacterial colonies per milliliter

4 • No more than 5.0% of samples may be total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than one
sample may be total coliform-positive during a month). Every sample that has total coliforms must be analyzed for either E. coli or fecal coliforms to determine whether human
Of animal fecal matter is present (fecal coliform and E. coli are part of the total coliform group). There may not be any fecal coliforms or E. coli.

5 - Foot) coliform and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Disease-causing microbes (pathogens) in
these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and people with
severely compromised immune systems.

6 • Although there is no collective MCLG for this contaminant group, there are individual MCLGs for some of the individual contaminants:
• Haloacetic acids: dichloroacetic acid (zero); trichloroacetic acid (0.3 mg/L)
• Trihalomethanes: bromodichloromethane (zero); bromoform (zero); dibromochloromethane (0.06 mg/L)

7 - MCLGs were not established before the 1986 Amendments to the Safe Drinking Water Act. The standard for this contaminant was set prior to 1986. Therefore, there is no
MCLO for this contaminant.

3 - Lead and copper arc regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the
action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L.

9 • Each water system must certify, in writing, to the state that when it uses acrylamide and/or epichlorohydrin to treat water, the combination (or product) of dose and monomer
level does not exceed the levels specified, as follows: Acrylamide = 0.05% dosed at 1 mg/L (or equivalent); Epichlorohydrin = 0.01% dosed at 20 mg/L (or equivalent).

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