Jump to main content or area navigation.

Contact Us

Water: Drinking Water

Drinking Water Health Advisories 2006 Edition

 

tapwater

Last update: August 2006; EPA 822-R-06-013

Print Version of these Tables (PDF) (18 pp., 85 K, About PDF)

Introduction

The Drinking Water Standards and Health Advisories Tables are revised periodically by EPA’s Office of Water in order to update RfD and Cancer values so that they are consistent with the most current Agency assessments of chemical contaminants that may occur in drinking water and to introduce new Health Advisories. The following information should be kept in mind when using the 2006 Edition of the Tables:

Reference dose (RfD) values are updated to reflect the values in the Integrated Risk Information System (IRIS) and the Office of Pesticide Programs (OPP) Reregistration Eligibility Decisions (RED) Documents. The Drinking Water Equivalent Level (DWEL) has been adjusted accordingly. Thus, both the RfD and DWEL in the Tables differ from the values in the Health Advisory document when the IRIS or OPP RfD is more recent than the Health Advisory document value. RfD values from IRIS that differ from the values in the Health Advisory documents are presented in BOLD type. Values derived from the REDs are given in BOLD italics. For unregulated chemicals with a recent IRIS or OPP RfD, the lifetime Health Advisory is calculated from the DWEL using the relative source contribution value published in the Health Advisory document. For regulated chemicals, no lifetime value is provided in the Tables when the revised lifetime value would differ from the Maximum Contaminant Level Goal (MCLG).

The cancer group designation or cancer classification and 10-4 cancer risk values reflect those presently in IRIS or in the OPP RED. New IRIS cancer designations and 10-4 cancer risk values are presented in BOLD type and those derived from the REDs are in BOLD italics.

IRIS Toxicological Reviews | OPP REDs

In some cases there is a Health Advisory value for a contaminant but there is no reference to a Health Advisory document. These Health Advisory values can be found in the Drinking Water Criteria Document for the contaminant.

With a few exceptions, the RfDs, Health Advisory, and cancer risk values have been rounded to one significant figure following the convention adopted by IRIS.

Copies of these Tables may be ordered free of charge from

SAFE DRINKING WATER HOTLINE
1-800-426-4791
Monday thru Friday, 9:00 AM to 5:30 PM EST

Top of page




Definitions

The following definitions for terms used in the Tables are not all-encompassing, and should not be construed to be "official" definitions. They are intended to assist the user in understanding terms found on the following pages.

Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow. It is the level of lead or copper which, if exceeded in over 10% of the homes tested, triggers treatment for corrosion control.

Cancer Classification: A descriptive weight-of-evidence judgment as to the likelihood that an agent is a human carcinogen and the conditions under which the carcinogenic effects may be expressed. Under the 2005 EPA Guidelines for Carcinogen Risk Assessment, descriptive terms for carcinogenicity replace the earlier alpha numeric Cancer Group designations (US EPA 1986 guidelines). The suggested descriptive terms are as follows:

  • Carcinogenic to humans (H)
  • Likely to be carcinogenic to humans (L)
  • Likely to be carcinogenic above a specified dose but not likely to be carcinogenic below that dose because a key event in tumor formation does not occur below that dose (L/N)
  • Suggestive evidence of carcinogenic potential (S)
  • Inadequate information to assess carcinogenic potential (I)
  • Not likely to be carcinogenic to humans (N)

The letter abbreviations provided parenthetically above are now used in the Tables in place of the prior alpha numeric identifiers for chemicals that have been evaluated under the new guidelines (the 2005 guidelines or the 1996 and 1999 draft guidelines).

Cancer Group: A qualitative weight-of-evidence judgement as to the likelihood that a chemical may be a carcinogen for humans. Each chemical was placed into one of the following five categories (US EPA 1986 guidelines). The Cancer Group designation are given in the Tables for chemicals that have not yet been evaluated under the new guidelines.

Group Category:

  • A: Human carcinogen
  • B: Probable human carcinogen —
    • B1: indicates limited human evidence
    • B2: indicates sufficient evidence in animals and inadequate or no evidence in humans
  • C: Possible human carcinogen
  • D: Not classifiable as to human carcinogenicity
  • E: Evidence of noncarcinogenicity for humans

10-4 Cancer Risk: The concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000.

Drinking Water Advisory: A nonregulatory concentration of a contaminant in water that is likely to be without adverse effects on health and aesthetics.

DWEL: Drinking Water Equivalent Level. A lifetime exposure concentration protective of adverse, non-cancer health effects, that assumes all of the exposure to a contaminant is from drinking water.

HA: Health Advisory. An estimate of acceptable drinking water levels for a chemical substance based on health effects information; a Health Advisory is not a legally enforceable Federal standard, but serves as technical guidance to assist Federal, State, and local officials.

One-Day HA: The concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to one day of exposure. The One-Day HA is normally designed to protect a 10-kg child consuming 1 liter of water per day.

Ten-Day HA: The concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure. The Ten-Day HA is also normally designed to protect a 10-kg child consuming 1 liter of water per day.

Lifetime HA: The concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for a lifetime of exposure. The Lifetime HA is based on exposure of a 70-kg adult consuming 2 liters of water per day. The Lifetime HA for Group C carcinogens includes an adjustment for possible carcinogenicity.

MCLG: Maximum Contaminant Level Goal. A non-enforceable health goal which is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety.

MCL: Maximum Contaminant Level. The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLG as feasible using the best available analytical and treatment technologies and taking cost into consideration. MCLs are enforceable standards.

RfD: Reference Dose. An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.

SDWR: Secondary Drinking Water Regulations. Non-enforceable Federal guidelines regarding cosmetic effects (such as tooth or skin discoloration) or aesthetic effects (such as taste, odor, or color) of drinking water.

TT: Treatment Technique. A required process intended to reduce the level of a contaminant in drinking water.

Top of page


Abbreviations

  • D: Draft
  • F: Final
  • NA: Not Applicable
  • NOAEL: No-Observed-Adverse-Effect Level
  • OPP: EPA's Office of Pesticide Programs
  • P: Proposed
  • Reg: Regulation
  • TT: Treatment Technique

Top of page


Drinking Water Standards, Organics

Organics, Summer 2006
Chemicals CASRN Number Standards Status HA Document Health Advisories Cancer Descriptor1
Status Reg. MCLG (mg/L) MCL (mg/L) 10-kg Child
One-day (mg/L) Ten-day (mg/L) RfD (mg/kg/day) DWEL (mg/L) Lifetime (mg/L) mg/L at 10-4 Cancer Risk
Acenaphthene 83-32-9 0.06 2
Acifluorfen (sodium) 62476-59-9   F'88 2 2 0.01 0.4 0.1 L/N
Acrylamide 79-06-1 F zero TT2 F'87 1.5 0.3 0.0002 0.007 0.0008 B2
Acrylonitrile 107-13-1   0.006 B1
Alachlor 15972-60-8 F zero 0.002 F'88 0.1 0.1 0.01 0.4 0.04 B2
Aldicarb3 116-06-3 F4 0.001 0.003 F'95 0.01 0.01 0.001 0.035 0.007 D
Aldicarb sulfone3 1646-88-4 F4 0.001 0.002 F'95 0.01 0.01 0.001 0.035 0.007 D
Aldicarb sulfoxide3 1646-87-3 F4 0.001 0.004 F'95 0.01 0.01 0.001 0.035 0.007 D
Aldrin 309-00-2 F'92 0.0003 0.0003 0.00003 0.001 0.0002 B2
Ametryn 834-12-8 F'88 9 9 0.009 0.3 0.06 D
Ammonium sulfamate 7773-06-0 F'88 20 20 0.2 8 2 D
Anthracene (PAH)5 120-12-7 0.3 10 D
Atrazine 1912-24-9 F 0.003 0.003 F'88 0.02 0.7 N
Baygon 114-26-1 F'88 0.04 0.04 0.004 0.1 0.003 C
Bentazon 25057-89-0 F'99 0.3 0.3 0.03 1 0.2 E
Benz[a]anthracene (PAH) 56-55-3 B2
Benzene 71-43-2 F zero 0.005 F'87 0.2 0.2 0.004 0.1 0.1 H
Benzo[a]pyrene (PAH) 50-32-8 F zero 0.0002 0.0005 B2
Benzo[b]fluoranthene (PAH) 205-99-2 B2
Benzo[g,h,i]perylene (PAH) 191-24-2 D
Benzo[k]fluoranthene (PAH) 207-08-9 B2
bis-2-Chloroisopropyl ether 39638-32-9 F'89 4 4 0.04 1 0.3 D
Bromacil 314-40-9 F'88 5 5 0.1 3.5 0.07 C
Bromobenzene 108-86-1 D'86 4 4 D
Bromochloromethane 74-97-5 F'89 50 1 0.01 0.5 0.09 D
Bromodichloromethane (THM) 75-27-4 F zero 0.081 1 0.6 0.003 0.1 0.1 L
Bromoform (THM) 75-25-2 F zero 0.081 5 0.2 0.03 1 0.8 L
Bromomethane 74-83-9 D'89 0.1 0.1 0.001 0.05 0.01 D
Butyl benzyl phthalate 85-68-7 0.2 7 C
Butylate 2008-41-5 F'89 2 2 0.05 2 0.4 D
Carbaryl 63-25-2 F'88 1 1 0.01 0.4 4 L
Carbofuran 1563-66-2 F 0.04 0.04 F'87 0.00006 N
Carbon tetrachloride 56-23-5 F zero 0.005 F'87 4 0.2 0.0007 0.03 0.03 B2
Carboxin 5234-68-4 F'88 1 1 0.1 3.5 0.7 D
Chloramben 133-90-4 F'88 3 3 0.015 0.5 0.1 D
Chlordane 57-74-9 F zero 0.002 F'87 0.06 0.06 0.0005 0.02 0.01 B2
Chloroform (THM) 67-66-3 F 0.07 0.086 4 4 0.01 0.35 0.07 L/N
Chloromethane 74-87-3 F'89 9 0.4 0.004 0.1 0.03 D
Chlorophenol (2-) 95-57-8 D'94 0.5 0.5 0.005 0.2 0.04 D
Chlorothalonil 1897-45-6 F'88 0.2 0.2 0.015 0.5 0.15 B2
Chlorotoluene o- 95-49-8 F'89 2 2 0.02 0.7 0.1 D
Chlorotoluene p- 106-43-4 F'89 2 2 0.02 0.7 0.1 D
Chlorpyrifos 2921-88-2 F'92 0.03 0.03 0.0003 0.01 0.002 D
Chrysene (PAH) 218-01-9 B2
Cyanazine 21725-46-2 D'96 0.1 0.1 0.002 0.07 0.001  
Cyanogen chloride7 506-77-4 0.05 0.05 0.05 2 D
2,4-D (2,4-dichlorophenoxyacetic acid) 94-75-7 F 0.07 0.07 F'87 1 0.3 0.005 0.2 D
DCPA (Dacthal) 1861-32-1 F'88 80 80 0.01 0.35 0.07 C
Dalapon (sodium salt) 75-99-0 F 0.2 0.2 F'89 3 3 0.03 0.9 0.2 D
Di(2-ethylhexyl)adipate 103-23-1 F 0.4 0.4 20 20 0.6 20 0.4 3 C
Di(2-ethylhexyl)phthalate 117-81-7 F zero 0.006 0.02 0.7 0.3 B2
Diazinon 333-41-5 F'88 0.02 0.02 0.0002 0.007 0.001 E
Dibromochloromethane (THM) 124-48-1 F 0.06 0.086 0.6 0.6 0.02 0.7 0.06 0.08 S
Dibromochloropropane (DBCP) 96-12-8 F zero 0.0002 F'87 0.2 0.05 0.003 B2
Dibutyl phthalate 84-74-2 0.1 4 D
Dicamba 1918-00-9 F'88 0.5 18 4 N
Dichloroacetic acid 76-43-6 F zero 0.068 5 5 0.004 0.1 0.07 L
Dichlorobenzene o- 95-50-1 F 0.6 0.6 F'87 9 9 0.09 3 0.6 D
Dichlorobenzene -9 541-73-1 F'87 9 9 0.09 3 0.6 D
Dichlorobenzene p- 106-46-7 F 0.075 0.075 F'87 11 11 0.1 4 0.075 C
Dichlorodifluoromethane 75-71-8 F'89 40 40 0.2 5 1 D
Dichloroethane (1,2-) 107-06-2 F zero 0.005 F'87 0.7 0.7 0.04 B2
Dichloroethylene (1,1-) 75-35-4 F 0.007 0.007 F'87 2 1 0.05 2 S
Dichloroethylene (cis-1,2-) 156-59-2 F 0.07 0.07 F'90 4 1 0.01 0.35 0.07 D
Dichloroethylene (trans-1,2-) 156-60-5 F 0.1 0.1 F'87 20 1 0.02 0.7 0.1 D
Dichloromethane 75-09-2 F zero 0.005 D'93 10 2 0.06 2 0.5 B2
Dichlorophenol (2,4-) 120-83-2 D'94 0.03 0.03 0.003 0.1 0.02 E
Dichloropropane (1,2-) 78-87-5 F zero 0.005 F'87 0.09 0.06 B2
Dichloropropene (1,3-) 542-75-6 F'88 0.03 0.03 0.03 1 0.04 L
Dieldrin 60-57-1 F'88 0.0005 0.0005 0.00005 0.002 0.0002 B2
Diethyl phthalate 84-66-2 0.8 30 D
Diisopropyl methylphosphonate 1445-75-6 F '89 8 8 0.08 3 0.6 D
Dimethrin 70-38-2 - F '88 10 10 0.3 10 2 D
Dimethyl methylphosphonate 756-79-6 - F '92 2 2 0.2 7 0.1 0.7 C
Dimethyl phthalate 131-11-3 - D
Dinitrobenzene (1,3-) 99-65-0 - F '91 0.04 0.04 0.0001 0.005 0.001 D
Dinitrotoluene (2,4-) 121-14-2 - F '92 0.50 0.50 0.002 0.1 0.005 B2
Dinitrotoluene (2,6-) 606-20-2 - F '92 0.4 0.4 0.001 0.04 0.005 B2
Dinitrotoluene (2,6 & 2,4)10   - F '92 0.005 B2
Dinoseb 88-85-7 F 0.007 0.007 F '88 0.3 0.3 0.001 0.035 0.007 D
Dioxane p- 123-91-1 - F '87 4 0.4 0.3 B2
Diphenamid 957-51-7 - F '88 0.3 0.3 0.03 1 0.2 D
Diquat 85-00-7 F 0.02 0.02 0.005 0.02 E
Disulfoton 298-04-4 - F '88 0.01 0.01 0.0001 0.0035 0.0007 E
Dithiane (1,4-) 505-29-3 - F '92 0.4 0.4 0.01 0.4 0.08 D
Diuron 330-54-1 - F '88 1 1 0.003 0.1 0.2 L
Endothall 145-73-3 F 0.1 0.1 F '88 0.8 0.8 0.007 0.25 0.05 N
Endrin 72-20-8 F 0.002 0.002 F '87 0.02 0.005 0.0003 0.01 0.002 D
Epichlorohydrin 106-89-8 F zero TT11 F '87 0.1 0.1 0 0.07 0.3 B2
Ethylbenzene 100-41-4 F 0.7 0.7 F '87 30 3 0.1 3 0.7 D
Ethylene dibromide (EDB)12 106-93-4 F zero 0.00005 F '87 0.008 0.008 0.009 0.3 0.002 L
Ethylene glycol 107-21-1 - F '87 20 6 2 70 14 D
Ethylene Thiourea (ETU) 96-45-7 - F '88 0.3 0.3 0.00008 0.003 0.02 B2
Fenamiphos 22224-92-6 F '88 0.009 0.009 0.0001 0.0035 0.0007 E
Fluometuron 2164-17-2 F '88 2 2 0.01 0.5 0.09   D
Fluorene (PAH) 86-73-7 - 0.04 1 D
Fonofos 944-22-9 - F '88 0.02 0.02 0.002 0.07 0.01 N
Formaldehyde 50-00-0 - D '93 10 5 0.2 7 1 B113
Glyphosate 1071-83-6 F 0.7 0.7 F '88 20 20 2 70 D
Heptachlor 76-44-8 F zero 0.0004 F '87 0.01 0.01 0.0005 0.02 0.0008 B2
Heptachlor epoxide 1024-57-3 F zero 0.0002 F '87 0.01 0.00001 0.0004 0.0004 B2
Hexachlorobenzene 118-74-1 F zero 0.001 F '87 0.05 0.05 0.0008 0.03 0.002 B2
Hexachlorobutadiene14 87-68-3 - 0.3 0.3 0 .0003 0.01 0.09 L
Hexachlorocyclopentadiene 77-47-4 F 0.05 0.05 0.006 0.2 N
Hexachloroethane 67-72-1 - F '91 5 5 0.001 0.04 0 0.3 C
Hexane (n-) 110-54-3 - F '87 10 4 I
Hexazinone 51235-04-2 - F '96 3 2 0.05 2 0.4 D
HMX15 2691-41-0 - F '88 5 5 0.05 2 0.4 D
Indeno[1,2,3,-c,d]pyrene (PAH) 193-39-5 - B2
Isophorone 78-59-1 - F '92 15 15 0.2 7 0.1 4 C
Isopropyl methylphosphonate 1832-54-8 - F '92 30 30 0.1 3.5 0.7 D
Isopropylbenzene (cumene) 98-82-8 - D '87 11 11 0.1 4 D
Lindane16 58-89-9 F 0 0.0002 F '87 1 1 0.005 0.2 S
Malathion 121-75-5 - F '92 0.2 0.2 0.02 0.8 0.1 D
Maleic hydrazide 123-33-1 - F '88 10 10 0.5 20 4 D
MCPA17 94-74-6 - F '88 0.1 0.1 0.004 0.14 0.03 N
Methomyl 16752-77-5 - F '88 0.3 0.3 0.025 0.9 0.2 E
Methoxychlor 72-43-5 F 0.04 0.04 F '87 0.05 0.05 0.005 0.2 0.04 D
Methyl ethyl ketone 78-93-3 - F '87 75 7.5 0.6 20 4 D
Methyl parathion 298-00-0 F '88 0.3 0.3 0.0002 0.007 0.001 N
Metolachlor 51218-45-2 F '88 2 2 0.1 3.5 0.7 C
Metribuzin 21087-64-9 - F '88 5 5 0.01 0.35 0.07 D
Monochloroacetic acid 79-11-8 F 0.03 0.068 0.2 0.2 0.01 0.35 0.07 I
Monochlorobenzene 108-90-7 F 0.1 0.1 F '87 4 4 0.02 0.7 0.1 D
Naphthalene 91-20-3 - F '90 0.5 0.5 0.02 0.7 0.1 I
Nitrocellulose18 9004-70-0 - F '88
Nitroguanidine 556-88-7 - F '90 10 10 0.1 3.5 0.7 D
Nitrophenol p- 100-02-7 - F '92 0.8 0.8 0.008 0.3 0.06 D
Oxamyl (Vydate) 23135-22-0 F 0.2 0.2 F '05 0.01 0.01 0.001 0.035
N
Paraquat 1910-42-5 - F '88 0.1 0.1 0.0045 0.2 0.03 C
Pentachlorophenol 87-86-5 F zero 0.001 F '87 1 0.3 0.03 1 0.03 B2
Phenanthrene (PAH) 85-01-8 - D
Phenol 108-95-2 - D '92 6 6 0.3 11 2 D
Picloram 1918-02-1 F 0.5 0.5 F '88 20 20 0.02 0.7 D
Polychlorinated biphenyls (PCBs) 1336-36-3 F zero 0.0005 D '93 0.01 B2
Prometon 1610-18-0 - F '88 0.2 0.2 0.02 0.5 0.1 D
Pronamide 23950-58-5 - F '88 0.8 0.8 0.08 3 0.2 B2
Propachlor 1918-16-7 - F '88 0.5 0.5 0.05 2 0.1 L
Propazine 139-40-2 - F '88 0.02 0.7 0.1 N
Propham 122-42-9 - F '88 5 5 0.02 0.6 0.1 D
Pyrene (PAH) 129-00-0 - 0.03 D
RDX19 121-82-4 - F '88 0.1 0.1 0 0.1 0.002 0.03 C
Simazine 122-34-9 F 0.004 0.004 F '88 0.02 0.7 N
Styrene 100-42-5 F 0.1 0.1 F '87 20 2 0.2 7 0.1 C
2,4,5-T (Trichlorophenoxy-acetic acid) 93-76-5 F '88 0.8 0.8 0.01 0.35 0.07 D
2,3,7,8-TCDD (Dioxin) 1746-01-6 F zero 3E-008 F ’87 1E-006 1E-007 1E-009 4E-008 2E-008 B2
Tebuthiuron 34014-18-1 - F '88 3 3 0.07 2 0.5 D
Terbacil 5902-51-2 - F '88 0.3 0.3 0.01 0.4 0.09 E
Terbufos 13071-79-9 - F '88 0.005 0.005 0.00005 0.002 0.0004 D
Tetrachloroethane (1,1,1,2-) 630-20-6 - F '89 2 2 0.03 1 0.07 0.1 C
Tetrachloroethane (1,1,2,2-) 79-34-5 - F '89 0.04 0.04 0.00005 0.002 0.0003 0.02 C
Tetrachloroethylene1 127-18-4 F zero 0.005 F '87 2 2 0.01 0.5 0.01
Trichlorofluoromethane 75-69-4 - F '89 7 7 0.3 10 2 D
Toluene 108-88-3 F 1 1 D '93 20 2 0.08 3 I
Toxaphene 8001-35-2 F zero 0.003 F '96 0.004 0.004 0.00004 0.01 0.003 B2
2,4,5-TP (Silvex) 93-72-1 F 0.05 0.05 F '88 0.2 0.2 0.008 0.3 0.05 D
Trichloroacetic acid 76-03-9 F 0.02 0.068 3 3 0.03 1 0.02 S
Trichlorobenzene (1,2,4-) 120-82-1 F 0.07 0.07 F '89 0.1 0.1 0.01 0.35 0.07 D
Trichlorobenzene (1,3,5-) 108-70-3 - F '89 0.6 0.6 0.006 0.2 0.04 D
Trichloroethane (1,1,1-) 71-55-6 F 0.2 0.2 F '87 100 40 0.035 1 0.2 D
Trichloroethane (1,1,2-) 79-00-5 F 0.003 0.005 F '89 0.6 0.4 0.004 0.1 0.003 0.06 C
Trichloroethylene7 79-01-6 F zero 0.005 F '87 0.007 0.2 0.3 B2
Trichlorophenol (2,4,6-) 06/02/88 - D '94 0.03 0.03 0.0003 0.01 0.3 B2
Trichloropropane (1,2,3-) 96-18-4 - F '89 0.6 0.6 0.006 0.2 0.04
Trifluralin 1582-09-8 - F '90 0.08 0.08 0.02 0.7 0.01 0.4 C
Trimethylbenzene (1,2,4-) 95-63-6 - D '87 D
Trimethylbenzene (1,3,5-) 108-67-8 - D '87 10 D
Trinitroglycerol 55-63-0 - F '87 0.005 0.005 0.005 0.2
Trinitrotoluene (2,4,6-) 118-96-7 - F '89 0.02 0.02 0.0005 0.02 0.002 0.1 C
Vinyl chloride 75-01-4 F zero 0.002 F '87 3 3 0.003 0.1 0.002 H
Xylenes 1330-20-7 F 10 10 D '93 40 40 0.2 7 I
Footnotes, Organics

1 Chemicals evaluated under the 2005 Cancer Guidelines or the 1996 or 1999 drafts are demoted by an abbreviation for their weight-of-the-evidence descriptor. If the agency has not completed a new assessment for the chemical, the 1986 Guidelines Group designation is given in the Cancer Descriptor column.

2 When acrylamide is used in drinking water systems, the combination (or product) of dose and monomer level shall not exceed that equivalent to a polyacrylamide polymer containing 0.05% monomer dosed at 1 mg/L.

3 The MCL value for any combination of two or more of these three chemicals should not exceed 0.007 mg/L because of a similar mode of action.

4 Administrative stay of the effective date.

5 PAH = Polycyclic aromatic hydrocarbon.

6 1998 Final Rule for Disinfectants and Disinfection By-products: The total for trihalomethanes (THM) is 0.08 mg/L.

7 Under review.

8 1998 Final Rule for Disinfectants and Disinfection By-products: The total for five haloacetic acids is 0.06 mg/L.

9 The values for m-dichlorobenzene are based on data for o-dichlorobenzene.

10 Technical grade.

11 When epichlorohydrin is used in drinking water systems, the combination (or product) of dose and monomer level shall not exceed that equivalent to an epichlorohydrin-based polymer containing 0.01% monomer dosed at 20 mg/L.

12 1,2-dibromoethane.

13 Carcinogenicity based on inhalation exposure.

14 Regulatory Determination Health Effects Support Document for Hexachlorobutadiene (PDF).

15 HMX = octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine.

16 Lindane = g - hexachlorocyclohexane.

17 MCPA = 4(chloro-2-methoxyphenoxy)acetic acid.

18 The Health Advisory Document for nitrocellulose does not include HA values and describes this compounds as relatively nontoxic.

19 RDX = hexahydro -1,3,5-trinitro-1,3,5-triazine.

Top of Page


Drinking Water Standards, Inorganics

Inorganics, Summer 2006
Chemicals CASRN Number Standards Status HA Document Health Advisories Cancer Descriptor 1
Status Reg. MCLG (mg/L) MCL (mg/L) 10-kg Child
One-day (mg/L) Ten-day (mg/L) RfD (mg/kg/day) DWEL (mg/L) Lifetime (mg/L) mg/L at 10-4Cancer Risk
Ammonia 7664-41-7 D '92 30 D
Antimony 7440-36-0 F 0.006 0.006 F '92 0.01 0.01 0.0004 0.01 0.006 D
Arsenic 7440-38-2 F zero 0.01 D '95 0.0003 0.01 0.002 A
Asbestos (fibers/l >10µm length) 1332-21-4 F 7 MFL1 7 MFL 700-MFL A2
Barium 7440-39-3 F 2 2 D '93 0.7 0.7 0.2 7 N
Beryllium 7440-41-7 F 0.004 0.004 F '92 30 30 0.002 0.07
Boron 7440-42-8 D '92 4 0.9 0.2 7 1 I
Bromate 7789-38-0 F zero 0.01 D '98 0.2 0.004 0.14 0.005 B2
Cadmium 7440-43-9 F 0.005 0.005 F ’87 0.04 0.04 0.0005 0.02 0.005 D
Chloramine3 10599-90-3 F 44 44 D '95 0.1 3.5 3
Chlorine 7782-50-5 F 44 44 D '95 3 3 0.1 5 4 D
Chlorine dioxide 10049-04-4 F 0.84 0.84 D '98 0.84 0.84 0.03 1 0.8 D
Chlorite 7758-19-2 F 0.8 1 D '98 0.84 0.84 0.03 1 0.8 D
Chromium (total) 7440-47-3 F 0.1 0.1 F '87 1 1 0.0035 0.1 D
Copper (at tap) 7440-50-8 F 1.3 TT6 D '98 D
Cyanide 143-33-9 F 0.2 0.2 F '87 0.2 0.2 0.027 0.8 0.2 D
Fluoride 7681-49-4 F 4 4 0.068
Lead (at tap) 7439-92-1 F zero TT6 B2
Manganese 7439-96-5 F'04 1 1 0.149 1.6 0.3 D
Mercury (inorganic) 7487-94-7 F 0.002 0.002 F '87 0.002 0.002 0.0003 0.01 0.002 D
Molybdenum 7439-98-7 D '93 0.08 0.08 0.005 0.2 0.04 D
Nickel 7440-02-0 F F '95 1 1 0.02 0.7 0.1
Nitrate (as N) 14797-55-8 F 10 10 D '93 1010 1010 1.6
Nitrite (as N) 14797-65-0 F 1 1 D '93 110 110 0.16
Nitrate + Nitrite (both as N)
F 10 10 D '93
Selenium 7782-49-2 F 0.05 0.05 0.005 0.2 0.05 D
Silver 7440-22-4 - F '92 0.2 0.2 0.00511 0.2 0.1 D
Strontium 7440-24-6 - D '93 25 25 0.6 20 4 D
Thallium 7440-28-0 F 0.0005 0.002 F '92 0.007 0.007 0.00007 0.002 0.0005
White phosphorous 7723-14-0 - F '90 0.00002 0.0005 0.0001
D
Zinc 7440-66-6 - D '93 6 6 0.3 10 2 I
Footnotes, Inorganics

1 MFL = million fibers per liter.

2 Carcinogenicity based on inhalation exposure.

3 Monochloramine; measured as free chlorine.

4 1998 Final Rule for Disinfectants and Disinfection By-products: MRDLG=Maximum Residual Disinfection Level Goal; and MRDL=Maximum Residual Disinfection Level.

5 IRIS value for chromium VI.

6 Copper action level 1.3 mg/L; lead action level 0.015 mg/L.

7 This RfD is for hydrogen cyanide.

8 Based on dental fluorosis in children, a cosmetic effect. MCLG based on skeletal fluorosis.

9 Dietary manganese. The lifetime health advisory includes a 3 fold modifying factor to account for increased bioavailability from drinking water.

10 These values are calculated for a 4-kg infant and are protective for all age groups.

11 Based on a cosmetic effect.

Top of page


Drinking Water Standards, Radionuclides

Radionuclides, Summer 2006
Chemicals CASRN Number Standards Status HA Document Health Advisories Cancer Descriptor 1
Status Reg. MCLG (mg/L) MCL (mg/L) 10-kg Child
One-day (mg/L) Ten-day (mg/L) RfD (mg/kg/day) DWEL (mg/L) Lifetime (mg/L) mg/L at 10-4Cancer Risk
Beta particle and photon activity (formerly man-made radionuclides)   F zero 4 mrem/yr 4 mrem/yr A
Gross alpha particle activity   F zero 15 pCi/L 15 pCi/L A
Combined Radium 226 & 228   F zero 5 pCi/L A
Radon   P zero 300 pCi/L
AMCL1
4000 pCi/L
150 pCi/L A
Uranium 7440-61-1 F zero 30 µg/L 0.00062 0.02 A
Footnotes, Radionuclides

1 AMCL = Alternative Maximum Contaminant Level.

2 Soluble uranium salts. Radionuclide Rule.

Top of page


Secondary Drinking Water Regulations

Chemicals CAS Number Status SDWR
Aluminum 7429-90-5 F 0.05 to 0.2 mg/L
Chloride 7647-14-5 F 250 mg/L
Color NA F 15 color units
Copper 7440-50-8 F 1.0 mg/L
Corrosivity NA F non-corrosive
Fluoride 7681-49-4 F 2.0 mg/L
Foaming agents NA F 0.5 mg/L
Iron 7439-89-6 F 0.3 mg/L
Manganese 7439-96-5 F 0.05 mg/L
Odor NA F 3 threshold odor numbers
pH NA F 6.5 – 8.5
Silver 7440-22-4 F 0.1 mg/L
Sulfate 7757-82-6 F 250 mg/L
Total dissolved solids (TDS) NA F 500 mg/L
Zinc 7440-66-6 F 5 mg/L

Top of page


Microbiology

  Status Reg. Status HA Document MCLG MCL Treatment Technique
Cryptosporidium F F 01 TT Systems that filter must remove 99% of Cryptosporidium
Giardia lamblia F F 98 TT 99.9% killed/inactivated
Legionella F1 F 01 zero TT No limit; EPA believes that if Giardia and viruses are inactivated, Legionella will also be controlled
Heterotrophic Plate Count (HPC) F1 NA TT No more than 500 bacterial colonies per milliliter.
Mycobacteria F 99
Total Coliforms F zero 5% No more than 5.0% samples total coliform-positive in a month. Every sample that has total coliforms must be analyzed for fecal coliforms; no fecal coliforms are allowed.
Turbidity F NA TT At no time can turbidity go above 5 NTU (nephelometric turbidity units)
Viruses F1 zero TT 99.99% killed/inactivated
Footnotes, Microbiology

1 - Final for systems using surface water; also being considered for regulation under groundwater disinfection rule.

Top of page


Drinking Water Advisory Table

Summer 2006  
Chemicals Status Heath-based Value Taste Threshold 1 Odor Threshold 2
Ammonia D '92 Not Available 30 mg/L  
Methyl tertiary butyl ether (MtBE) F '98 Not Available 40 µg/L 20 µg/L
Sodium F '03 20 mg/L (for individuals on a 500 mg/day restricted sodium diet). 30–60 mg/L  
Sulfate F '03 500 mg/L 250 mg/L  
Footnotes, Advisory

1 Taste Threshold: Concentration at which the majority of consumers do not notice an adverse taste in drinking water; it is recognized that some sensitive individuals may detect a chemical at levels below this threshold.

2 Odor Threshold: Concentration at which the majority of consumers do not notice an adverse odor in drinking water; it is recognized that some sensitive individuals may detect a chemical at levels below this threshold.

Top of page


Jump to main content.