National Primary
Drinking Water Regulations
SEFft
Contaminant
MCL or IT
(mg/L)2
Potential health effects
from long-term3 exposure
above the MCL
Common sources of contaminant in
drinking water
Public Health
Coal (mg/L)2
0
Acrylamide
TT4
Nervous system or blood
problems; increased risk of cancer
Added to water during sewage/
wastewater treatment
zero
0
Alachlor
0.002
Eye, liver, kidney, or spleen
problems; anemia; increased risk
of cancer
Runoff from herbicide used on row
crops
zero
©
Alpha/photon
emitters
15 picocuries
per Liter
(pCi/L)
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
zero

Antimony
0.006
Increase in blood cholesterol;
decrease in blood sugar
Discharge from petroleum refineries;
fire retardants; ceramics; electronics;
solder
0.006

Arsenic
0.010
Skin damage or problems with
circulatory systems, and may have
increased risk of getting cancer
Erosion of natural deposits; runoff
from orchards; runoff from glass &
electronics production wastes
0

Asbestos
(fibers >10
micrometers)
7 million
fibers per Liter
(MFL)
Increased risk of developing
benign intestinal polyps
Decay of asbestos cement in water
mains; erosion of natural deposits
7 MFL
0
Atrazine
0.003
Cardiovascular system or
reproductive problems
Runoff from herbicide used on row
crops
0.003

Barium
2
Increase in blood pressure
Discharge of drilling wastes; discharge
from metal refineries; erosion
of natural deposits
2
0
Benzene
0.005
Anemia; decrease in blood
platelets; increased risk of cancer
Discharge from factories; leaching
from gas storage tanks and landfills
zero
0
Benzo(a)pyrene
(PAHs)
0.0002
Reproductive difficulties;
increased risk of cancer
Leaching from linings of water storage
tanks and distribution lines
zero

Beryllium
0.004
Intestinal lesions
Discharge from metal refineries and
coal-burning factories; discharge
from electrical, aerospace, and
defense industries
0.004
©
Beta photon
emitters
4 millirems
per year
Increased risk of cancer
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
zero
&
Bromate
0.010
Increased risk of cancer
Byproduct of drinking water
disinfection
zero

Cadmium
0.005
Kidney damage
Corrosion of galvanized pipes; erosion
of natural deposits; discharge
from metal refineries; runoff from
waste batteries and paints
0.005
0
Carbofuran
0.04
Problems with blood, nervous
system, or reproductive system
Leaching of soil fumigant used on rice
and alfalfa
0.04
LEGEND
DISINFECTANT
A
DISINFECTION
BYPRODUCT
(^O
INORGANIC
CHEMICAL
MICROORGANISM
ORGANIC
CHEMICAL
RADIONUCLIDES

-------
National Primary Drinking Water Regulations
EPA 816-F-09-004 | MAY 2009

Contaminant
MCL orTT
(mg/L)2
Potential health effects
from long-term3 exposure
above the MCL
Common sources of contaminant
in drinking water
Public Health
Coal (mg/L)2
0
Carbon
tetrachloride
0.005
Liver problems; increased risk of
cancer
Discharge from chemical plants and
other industrial activities
zero
5
Chloramines
(as cy
MRDL=4.01
Eye/nose irritation; stomach
discomfort; anemia
Water additive used to control
microbes
MRDLG=41
0
Chlordane
0.002
Liver or nervous system problems;
increased risk of cancer
Residue of banned termiticide
zero
5
Chlorine
(as Cl2)
MRDL=4.01
Eye/nose irritation; stomach
discomfort
Water additive used to control
microbes
MRDLG=41
5
Chlorine dioxide
(as CI02)
MRDL=0.81
Anemia; infants, young children,
and fetuses of pregnant women:
nervous system effects
Water additive used to control
microbes
MRDLC=0.81
&
Chlorite
1.0
Anemia; infants, young children,
and fetuses of pregnant women:
nervous system effects
Byproduct of drinking water
disinfection
0.8
Chlorobenzene
0.1
Liver or kidney problems
Discharge from chemical and
agricultural chemical factories
0.1

Chromium (total)
0.1
Allergic dermatitis
Discharge from steel and pulp mills;
erosion of natural deposits
0.1
4?
Copper
TT5; Action
Level=1.3
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
Corrosion of household plumbing
systems; erosion of natural deposits
1.3
©
Cryptosporidium
TT7
Short-term exposure:
Gastrointestinal illness (e.g.,
diarrhea, vomiting, cramps)
Human and animal fecal waste
zero
4
Cyanide
(as free cyanide)
0.2
Nerve damage or thyroid
problems
Discharge from steel/metal
factories; discharge from plastic and
fertilizer factories
0.2
0
2,4-D
0.07
Kidney, liver, or adrenal gland
problems
Runoff from herbicide used on row
crops
0.07
0
Dalapon
0.2
Minor kidney changes
Runoff from herbicide used on
rights of way
0.2
0
l,2-Dibromo-3-
chioropropane
(DBCP)
0.0002
Reproductive difficulties;
increased risk of cancer
Runoff/leaching from soil fumigant
used on soybeans, cotton,
pineapples, and orchards
zero
o-Dichlorobenzene
0.6
Liver, kidney, or circulatory system
problems
Discharge from industrial chemical
factories
0.6
0
p-Dichlorobenzene
0.075
Anemia; liver, kidney, or spleen
damage; changes in blood
Discharge from industrial chemical
factories
0.075
0
1,2-Dichioroethane
0.005
Increased risk of cancer
Discharge from industrial chemical
factories
zero
LEGEND
DISINFECTANT
£
DISINFECTION
BYPRODUCT
INORGANIC
CHEMICAL
o ©
MICROORGANISM
ORGANIC
CHEMICAL
RADIONUCLIDES

-------
National Primary Drinking Water Regulations
EPA 816-F-09-004 | MAY 2009

Contaminant
MCL orTT
(mg/L)2
Potential health effects
from long-term3 exposure
above the MCL
Common sources of
contaminant in drinking water
Public Health
Coal (mg/L)2
0
1,1-Dichloroethylene
0.007
Liver problems
Discharge from industrial
chemical factories
0.007
0
cis-1,2-
Dichloroethylene
0.07
Liver problems
Discharge from industrial
chemical factories
0.07
0
trans-1,2,
Dichloroethylene
0.1
Liver problems
Discharge from industrial
chemical factories
0.1
0
Dichloromethane
0.005
Liver problems; increased risk of
cancer
Discharge from industrial
chemical factories
zero
0
1,2-Dichloropropane
0.005
Increased risk of cancer
Discharge from industrial
chemical factories
zero
0
Di(2-ethylhexyl)
adipate
0.4
Weight loss, liver problems, or
possible reproductive difficulties
Discharge from chemical
factories
0.4
0
Di(2-ethylhexyl)
phthalate
0.006
Reproductive difficulties; liver
problems; increased risk of cancer
Discharge from rubber and
chemical factories
zero
0
Dinoseb
0.007
Reproductive difficulties
Runoff from herbicide used on
soybeans and vegetables
0.007
0
Dioxin (2,3,7,8-TCDD)
0.00000003
Reproductive difficulties; increased
risk of cancer
Emissions from waste
incineration and other
combustion; discharge from
chemical factories
zero
0
Diquat
0.02
Cataracts
Runoff from herbicide use
0.02
0
Endothall
0.1
Stomach and intestinal problems
Runoff from herbicide use
0.1
0
Endrin
0.002
Liver problems
Residue of banned insecticide
0.002
0
Epichlorohydrin
TT4
Increased cancer risk; stomach
problems
Discharge from industrial
chemical factories; an impurity
of some water treatment
chemicals
zero
0
Ethylbenzene
0.7
Liver or kidney problems
Discharge from petroleum
refineries
0.7
0
Ethylene dibromide
0.00005
Problems with liver, stomach,
reproductive system, or kidneys;
increased risk of cancer
Discharge from petroleum
refineries
zero
©
Fecal coliform and
E. coli
MCL6
Fecal coliforms and E. coli are
bacteria whose presence indicates
that the water may be contaminated
with human or animal wastes.
Microbes in these wastes may cause
short term effects, such as diarrhea,
cramps, nausea, headaches, or
other symptoms. They may pose a
special health risk for infants, young
children, and people with severely
compromised immune systems.
Human and animal fecal waste
zero6
LEGEND
DISINFECTANT
£
DISINFECTION
BYPRODUCT
INORGANIC
CHEMICAL
o ©
MICROORGANISM
ORGANIC
CHEMICAL
RADIONUCLIDES

-------
National Primary Drinking Water Regulations
EPA 816-F-09-004 | MAY 2009

Contaminant
MCL orTT
(mg/L)2
Potential health effects
from long-term3 exposure
above the MCL
Common sources of contaminant
in drinking water
Public Health
Coal (mg/L)2

Fluoride
4.0
Bone disease (pain and
tenderness of the bones); children
may get mottled teeth
Water additive which promotes
strong teeth; erosion of natural
deposits; discharge from fertilizer
and aluminum factories
4.0
©
Ciardia lamblia
TT7
Short-term exposure:
Gastrointestinal illness (e.g.,
diarrhea, vomiting, cramps)
Human and animal fecal waste
zero
0
Glyphosate
0.7
Kidney problems; reproductive
difficulties
Runoff from herbicide use
0.7
A
Haloacetic acids
(HAA5)
0.060
Increased risk of cancer
Byproduct of drinking water
disinfection
n/a9
0
Heptachlor
0.0004
Liver damage; increased risk of
cancer
Residue of banned termiticide
zero
0
Heptachior epoxide
0.0002
Liver damage; increased risk of
cancer
Breakdown of heptachlor
zero

Heterotrophic plate
count (HPC)
TT7
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 the water system is.
HPC measures a range of bacteria
that are naturally present in the
environment
n/a
0
Hexachlorobenzene
0.001
Liver or kidney problems;
reproductive difficulties; increased
risk of cancer
Discharge from metal refineries
and agricultural chemical factories
zero
0
Hexachloro-
cyclopentadiene
0.05
Kidney or stomach problems
Discharge from chemical factories
0.05
4
Lead
TT5; Action
Level=0.015
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
Corrosion of household plumbing
systems; erosion of natural deposits
zero
vOy
Legionella
TT7
Legionnaire's Disease, a type of
pneumonia
Found naturally in water; multiplies
in heating systems
zero
0
Lindane
0.0002
Liver or kidney problems
Runoff/leaching from insecticide
used on cattle, lumber, and gardens
0.0002

Mercury (inorganic)
0.002
Kidney damage
Erosion of natural deposits;
discharge from refineries and
factories; runoff from landfills and
croplands
0.002
0
Methoxychlor
0.04
Reproductive difficulties
Runoff/leaching from insecticide
used on fruits, vegetables, alfalfa,
and livestock
0.04
4
Nitrate (measured
as Nitrogen)
10
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.
Runoff from fertilizer use; leaching
from septic tanks, sewage; erosion
of natural deposits
10
LEGEND
DISINFECTANT
£
DISINFECTION
BYPRODUCT
INORGANIC
CHEMICAL
o ©
MICROORGANISM
ORGANIC
CHEMICAL
RADIONUCLIDES

-------
National Primary Drinking Water Regulations
EPA 816-F-09-004 | MAY 2009

Contaminant
MCL orTT
(mg/L)2
Potential health effects
from long-term3 exposure
above the MCL
Common sources of contaminant
in drinking water
Public Health
Coal (mg/L)2

Nitrite (measured
as Nitrogen)
1
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.
Runoff from fertilizer use; leaching
from septic tanks, sewage; erosion
of natural deposits
1
0
Oxamyl (Vydate)
0.2
Slight nervous system effects
Runoff/leaching from insecticide
used on apples, potatoes, and
tomatoes
0.2
Pentachlorophenol
0.001
Liver or kidney problems;
increased cancer risk
Discharge from wood-preserving
factories
zero
0
Picloram
0.5
Liver problems
Herbicide runoff
0.5
0
Polychlorinated
biphenyis (PCBs)
0.0005
Skin changes; thymus gland
problems; immune deficiencies;
reproductive or nervous system
difficulties; increased risk of
cancer
Runoff from landfills; discharge of
waste chemicals
zero
©
Radium 226
and Radium 228
(combined)
5 pCi/L
Increased risk of cancer
Erosion of natural deposits
zero

Selenium
0.05
Hair or fingernail loss; numbness
in fingers or toes; circulatory
problems
Discharge from petroleum and
metal refineries; erosion of natural
deposits; discharge from mines
0.05
0
Simazine
0.004
Problems with blood
Herbicide runoff
0.004
0
Styrene
0.1
Liver, kidney, or circulatory system
problems
Discharge from rubber and plastic
factories; leaching from landfills
0.1
0
Tetrachloroethylene
0.005
Liver problems; increased risk of
cancer
Discharge from factories and dry
cleaners
zero

Thallium
0.002
Hair loss; changes in blood; kidney,
intestine, or liver problems
Leaching from ore-processing sites;
discharge from electronics, glass,
and drug factories
0.0005
0
Toluene
1
Nervous system, kidney, or liver
problems
Discharge from petroleum
factories
1
vOy
Total Coliforms
5.0 percent8
Coliforms are bacteria that
indicate that other, potentially
harmful bacteria may be present.
See fecal coliforms and E. coli
Naturally present in the
environment
zero
&
Total
Trihalomethanes
(TTHMs)
0.080
Liver, kidney, or central nervous
system problems; increased risk
of cancer
Byproduct of drinking water
disinfection
n/a9
0
Toxaphene
0.003
Kidney, liver, or thyroid problems;
increased risk of cancer
Runoff/leaching from insecticide
used on cotton and cattle
zero
0
2,4,5-TP (Silvex)
0.05
Liver problems
Residue of banned herbicide
0.05
0
1,2,4-
Trichlorobenzene
0.07
Changes in adrenal glands
Discharge from textile finishing
factories
0.07
LEGEND
DISINFECTANT
£
DISINFECTION
BYPRODUCT
INORGANIC
CHEMICAL
o ©
MICROORGANISM
ORGANIC
CHEMICAL
RADIONUCLIDES

-------
National Primary Drinking Water Regulations	EPA 816-F-09-004 | MAY 2009
Contaminant
MCL or
TT1
(mg/L)2
Potential health effects
from long-term3 exposure
above the MCL
Common sources of
contaminant in drinking
water
Public Health
Coal (mg/L)2
0
1,1,1-
Trichloroethane
0.2
Liver, nervous system, or circulatory problems
Discharge from metal
degreasing sites and other
factories
0.2
0
1,1,2-
Trichloroethane
0.005
Liver, kidney, or immune system problems
Discharge from industrial
chemical factories
0.003
0
Trichioroethyiene
0.005
Liver problems; increased risk of cancer
Discharge from metal
degreasing sites and other
factories
zero
m)
Turbidity
TT7
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 short term symptoms such as nausea,
cramps, diarrhea, and associated headaches.
Soil runoff
n/a
©
Uranium
30|jg/L
Increased risk of cancer, kidney toxicity
Erosion of natural deposits
zero
Vinyl chloride
0.002
Increased risk of cancer
Leaching from PVC pipes;
discharge from plastic factories i
zero

Viruses (enteric)
TT7
Short-term exposure: Gastrointestinal illness
(e.g., diarrhea, vomiting, cramps)
Human and animal fecal
waste
zero
Xylenes (total)
10
Nervous system damage
Discharge from petroleum
factories; discharge from
chemical factories
10
LEGEND
DISINFECTANT
&
DISINFECTION
BYPRODUCT
4*
INORGANIC
CHEMICAL
vOJ
o ©
MICROORGANISM
ORGANIC
CHEMICAL
RADIONUCLIDES
NOTES
1	Definitions
¦	Maximum Contaminant Level Coal (MCLG):The level of a contaminant in drinking
water below which there is no known or expected risk to health. MCLCs 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 MCLCs as feasible using the
best available treatment technology and taking cost into consideration. MCLs are
enforceable standards.
¦	Maximum Residual Disinfectant Level Coal (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 are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are
equivalent to parts per million (ppm).
3	Health effects are from long-term exposure unless specified as short-term exposure.
4	Each water system must certify annually in writing, to the state (using third-party or
manufacturers certification) 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 percent dosed at 1 mg/L (or equivalent);
Epichlorohydrin = 0.01 percent dosed at 20 mg/L (or equivalent).
5	Lead and copper are regulated by a Treatment Technique that requires systems to
control the corrosiveness of their water. If more than 10 percent 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.
6	A routine sample that is fecal coliform-positive or E. coli-positive triggers repeat samples-
-if any repeat sample is total coliform-positive, the system has an acute MCL violation. A
routine sample that is total coliform-positive and fecal coliform-negative or E. coli-
negative triggers repeat samples-if any repeat sample is fecal coliform-positive or E.
coli-positive, the system has an acute MCL violation. See also Total Coliforms.
7	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: 99 percent removal for systems that filter. Unfiltered systems are
required to include Cryptosporidium in their existing watershed control provisions.
¦	Ciardia lamblia: 99.9 percent removal/inactivation
¦	Viruses: 99.9 percent removal/inactivation
¦	Legionella: No limit, but EPA believes that if Ciardia and viruses are removed/
inactivated, according to the treatment techniques in the surface water treatment rule,
Legionella will also be controlled.
¦	Turbidity: For systems that use conventional or direct filtration, at no time can turbidity
(cloudiness of water) go higher than 1 nephelometric turbidity unit (NTU), and samples
for turbidity must be less than or equal to 0.3 NTU in at least 95 percent of the samples
in any month. Systems that use filtration other than the conventional or direct filtration
must follow state limits, which must include turbidity at no time exceeding 5 NTU.
HPC: No more than 500 bacterial colonies per milliliter
¦	Long Term 1 Enhanced Surface Water Treatment: Surface water systems or ground
water systems under the direct influence of surface water serving fewer than 10,000
people must comply with the applicable Long Term 1 Enhanced Surface Water
Treatment Rule provisions (e.g. turbidity standards, individual filter monitoring,
Cryptosporidium removal requirements, updated watershed control requirements for
unfiltered systems).
¦	Long Term 2 Enhanced Surface Water Treatment: This rule applies to all surface water
systems or ground water systems under the direct influence of surface water. The rule
targets additional Cryptosporidium treatment requirements for higher risk systems
and includes provisions to reduce risks from uncovered finished water storages facilities
and to ensure that the systems maintain microbial protection as they take steps to
reduce the formation of disinfection byproducts. (Monitoring start dates are staggered
by system size. The largest systems (serving at least 100,000 people) will begin
monitoring in October 2006 and the smallest systems (serving fewer than 10,000
people) will not begin monitoring until October 2008. After completing monitoring
and determining their treatment bin, systems generally have three years to comply
with any additional treatment requirements.)
¦	Filter Backwash Recycling: The Filter Backwash Recycling Rule requires systems that
recycle to return specific recycle flows through all processes of the system's existing
conventional or direct filtration system or at an alternate location approved by the state.
8	No more than 5.0 percent samples total coliform-positive in a month. (For water systems
that collect fewer than 40 routine samples per month, no more than one sample can be
total coliform-positive per month.) Every sample that has total col iform must be analyzed
for either fecal coliforms or E. coli. If two consecutive TC-positive samples, and one is also
positive for E. coli or fecal coliforms, system has an acute MCL violation.
9	Although there is no collective MCLC for this contaminant group, there are individual
MCLCs 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)

-------
National Primary Drinking Water Regulations
EPA 816-F-09-004 | MAY 2009
NATIONAL SECONDARY DRINKING WATER REGULATION
National Secondary Drinking Water Regulations are non-enforceable guidelines regarding contaminants
that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste,
odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not
require systems to comply. However, some states may choose to adopt them as enforceable standards.
Contaminant
Secondary Maximum Contaminant Level
Aluminum
0.05 to 0.2 mg/L
Chloride
250 mg/L
Color
15 (color units)
Copper
1.0 mg/L
Corrosivity
Noncorrosive
Fluoride
2.0 mg/L
Foaming Agents
0.5 mg/L
Iron
0.3 mg/L
Manganese
0.05 mg/L
Odor
3 threshold odor number
PH
6.5-8.5
Silver
0.10 mg/L
Sulfate
250 mg/L
Total Dissolved Solids
500 mg/L
Zinc
5 mg/L
FOR MORE INFORMATION ON EPA'S
SAFE DRINKING WATER:
Q1 visit: epa.gov/safewater
% call: (800)426^791
ADDITIONAL INFORMATION:
To order additional posters or other ground
water and drinking water publications,
please contact the National Service Center for
Environmental Publications at: (800)490-9198,
or email: nscep@bps-lmit.com.

OFFICE OF GROUND WATER
AND DRINKING WATER

-------