APPENDIX A-2
 

NATIONAL PRIMARY DRINKING WATER STANDARDS
 
 

NATIONAL PRIMARY DRINKING WATER STANDARDS
 

Contaminants MCLG (mg/L) 1 4 MCL or TT (mg/L) 2 3 4 

Inorganic Chemicals 

Antimony 0.006 0.006 

Arsenic none5 0.01 

Asbestos (fiber > 10 micrometers) 7 million fibers per Liter 7 MFL 

Barium 2 2 

Beryllium 0.004 0.004 

Cadmium 0.005 0.005 

Chromium (total) 0.1 0.1 

Copper 1.3 Action Level= 1.3; TT6 

Cyanide (as free cyanide) 0.2 0.2 

Fluoride 4.0 4.0 

Lead zero Action Level= 0.015; TT6 

Inorganic Mercury 0.002 0.002 

Nitrate (measured as Nitrogen) 10 10 

Nitrite (measured as Nitrogen) 1 1 

Selenium 0.05 0.05 

Thallium 0.0005 0.002 

Organic Chemicals 

Acrylamide zero 1 mg/L equivalent TT7 

Alachlor zero 0.002 

Atrazine 0.003 0.003 

Benzene zero 0.005 

Benzo[a]pyrene zero 0.0002 

Carbofuran 0.04 0.04 

Carbon Tetrachloride zero 0.005 

Chlordane zero 0.002 

Chlorobenzene 0.1 0.1 

Chlorine 4.0 MRDLG 8 4.0 MRDL 8 

2,4-D 0.07 0.07 

Dalapon 0.2 0.2 

1,2-Dibromo-3-chloropropane (DBCP) zero 0.0002 

o-Dichlorobenzene 0.6 0.6 

p-Dichlorobenzene 0.075 0.075 

1,2-Dichloroethane zero 0.005 

1-1-Dichloroethylene 0.007 0.007 

cis-1, 2-Dichloroethylene 0.07 0.07 

trans-1,2-Dichloroethylene 0.1 0.1 

Dichloromethane zero 0.005 

1-2-Dichloropropane zero 0.005 

Di(2-ethylhexyl)adipate 0.4 0.4 

Di(2-ethylhexyl)phthalate zero 0.006 

Dinoseb 0.007 0.007 

Dioxin (2,3,7,8-TCDD) zero 0.00000003 

Diquat 0.02 0.02 

Endothall 0.1 0.1 

Endrin 0.002 0.002 

A-2-1 
 

 

 

 

 

NATIONAL PRIMARY DRINKING WATER STANDARDS (CONTINUED)
 

Contaminants MCLG (mg/L) 1 4 MCL or TT (mg/L) 2 3 4 

Epichlorohydrin zero 20 mg/L equivalent TT7 

Ethylbenzene 0.7 0.7 

Ethylene Dibromide zero 0.00005 

Glyphosate 0.7 0.7 

Heptachlor zero 0.0004 

Heptachlor Epoxide zero 0.0002 

Hexachlorobenzene zero 0.001 

Hexachlorocyclopentadiene 0.05 0.05 

Lindane 0.0002 0.0002 

Methoxychlor 0.04 0.04 

Oxamyl (Vydate) 0.2 0.2 

Polychlorinated biphenyls (PCBs) zero 0.0005 

Pentachlorophenol zero 0.001 

Picloram 0.5 0.5 

Simazine 0.004 0.004 

Styrene 0.1 0.1 

Tetrachloroethylene zero 0.005 

Toluene 1 1 

Total Trihalomethanes (TTHMs) 

including:

 Bromodichloromethane

 Bromoform

 Chloroform

 Dibromochloromethane 

none5 0.08 

Toxaphene zero 0.003 

2,4,5-TP (Silvex) 0.05 0.05 

1,2,4-Trichlorobenzene 0.07 0.07 

1,1,1-Trichloroethane 0.20 0.2 

1,1,2-Trichloroethane 0.003 0.005 

Trichloroethylene zero 0.005 

Vinyl Chloride zero 0.002 

Xylenes (total) 10 10 

Notes 

1	 M aximum Contaminant Level Goal (MCLG) - The maximum level of a contaminant in drinking water at which no known or anticipated adverse 

effect on the health effect of persons would occur, and which allows for an adequate margin of safety. MCLGs are non-enforceable public health 

goals. 2	 Maximum Contaminant Level (MCL) - The maximum permissible level of a contaminant in water which is delivered to any user of a public 

water system. MCLs are enforceable standards. The margins of safety in MCLGs ensure that exceeding the MCL slightly does not pose 

significant risk to public health. 3	 Treatment Technique - An enforceable procedure or level of technical performance which public water systems must follow to ensure control 

of a contaminant. 4	 Units are in milligrams per Liter (mg/L) unless otherwise noted. 5	 MCLGs were not established before the 1986 Amendments to the Safe Drinking Water Act. Therefore, there is no MCLG for this contaminant. 6	 Lead and copper are regulated in a Treatment Technique which requires systems to take tap water samples at sites with lead pipes or copper pipes 

that have lead solder and/or are served by lead service lines. The action level, which triggers water systems into taking treatment steps if 

exceeded in more than 10% of tap water samples, for copper is 1.3 mg/L, and for lead is 0.015mg/L. 7	 Each water system must certify, in writing, to the state (using third-party or manufacturer' s certification) that when acrylamide and 

epichlorohydrin are used in drinking water systems, 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) 8	 Maximum Residual Disinfectant Level Goals and Levels (MRDLG and MRDL). 

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