SUBPART - Subpart F—Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals

Collapse to view only § 141.54 - Maximum residual disinfectant level goals for disinfectants.

§ 141.50 - Maximum contaminant level goals for organic contaminants.
§ 141.51 - Maximum contaminant level goals for inorganic contaminants.
§ 141.52 - Maximum contaminant level goals for microbiological contaminants.
§ 141.53 - Maximum contaminant level goals for disinfection byproducts.
§ 141.54 - Maximum residual disinfectant level goals for disinfectants.
§ 141.55 - Maximum contaminant level goals for radionuclides.

§ 141.50 - Maximum contaminant level goals for organic contaminants.

(a) MCLGs are zero for the following contaminants:

(1) Benzene.

(2) Vinyl chloride.

(3) Carbon tetrachloride.

(4) 1,2-dichloroethane.

(5) Trichloroethylene.

(6) Acrylamide.

(7) Alachlor.

(8) Chlordane.

(9) Dibromochloropropane.

(10) 1,2-Dichloropropane.

(11) Epichlorohydrin.

(12) Ethylene dibromide.

(13) Heptachlor.

(14) Heptachlor epoxide.

(15) Pentachlorophenol.

(16) Polychlorinated biphenyls (PCBs).

(17) Tetrachloroethylene.

(18) Toxaphene.

(19) Benzo[a]pyrene.

(20) Dichloromethane (methylene chloride).

(21) Di(2-ethylhexyl)phthalate.

(22) Hexachlorobenzene.

(23) 2,3,7,8-TCDD (Dioxin).

(24) PFOA.

(25) PFOS.

(b) MCLGs for the following contaminants are as indicated:

Contaminant	MCLG in mg/l (unless otherwise noted)	(1) 1,1-Dichloroethylene	0.007	(2) 1,1,1-Trichloroethane	0.20	(3) para-Dichlorobenzene	0.075	(4) Aldicarb	0.001	(5) Aldicarb sulfoxide	0.001	(6) Aldicarb sulfone	0.001	(7) Atrazine	0.003	(8) Carbofuran	0.04	(9) o-Dichlorobenzene	0.6	(10) cis-1,2-Dichloroethylene	0.07	(11) trans-1,2-Dichloroethylene	0.1	(12) 2,4-D	0.07	(13) Ethylbenzene	0.7	(14) Lindane	0.0002	(15) Methoxychlor	0.04	(16) Monochlorobenzene	0.1	(17) Styrene	0.1	(18) Toluene	1	(19) 2,4,5-TP	0.05	(20) Xylenes (total)	10	(21) Dalapon	0.2	(22) Di(2-ethylhexyl)adipate	.4	(23) Dinoseb	.007	(24) Diquat	.02	(25) Endothall	.1	(26) Endrin	.002	(27) Glyphosate	.7	(28) Hexachlorocyclopentadiene	.05	(29) Oxamyl (Vydate)	.2	(30) Picloram	.5	(31) Simazine	.004	(32) 1,2,4-Trichlorobenzene	.07	(33) 1,1,2-Trichloroethane	.003	(34) Hazard Index PFAS (HFPO-DA, PFBS, PFHxS, and PFNA)	1 (unitless). 1	(35) HFPO-DA	0.00001.	(36) PFHxS	0.00001.	(37) PFNA	0.00001.

1 The PFAS Mixture Hazard Index (HI) is the sum of component hazard quotients (HQs), which are calculated by dividing the measured component PFAS concentration in water by the corresponding contaminant's health-based water concentration (HBWC) when expressed in the same units (shown in ng/l). The HBWC for PFHxS is 10 ng/l; the HBWC for HFPO-DA is 10 ng/l; the HBWC for PFNA is 10 ng/l; and the HBWC for PFBS is 2000 ng/l. A PFAS Mixture Hazard Index greater than 1 (unitless) indicates an exceedance of the health protective level and indicates potential human health risk from the PFAS mixture in drinking water.

Hazard Index = ([HFPO-DAwater ng/l]/[10 ng/l]) + ([PFBSwater ng/l]/[2000 ng/l]) + ([PFNAwater ng/l]/[10 ng/l]]) + ([PFHxSwater ng/l]/[10 ng/l]) HBWC = health-based water concentration HQ = hazard quotient ng/l = nanograms per liter PFASwater = the concentration of a specific PFAS in water [50 FR 46901, Nov. 13, 1985, as amended at 52 FR 20674, June 2, 1987; 52 FR 25716, July 8, 1987; 56 FR 3592, Jan. 30, 1991; 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 89 FR 32744, April 25, 2024]

§ 141.51 - Maximum contaminant level goals for inorganic contaminants.

(a) [Reserved]

(b) MCLGs for the following contaminants are as indicated:

Contaminant	MCLG (mg/l)	Antimony	0.006	Arsenic	zero 1	Asbestos	7 Million fibers/liter (longer than 10 µm).	Barium	2	Beryllium	.004	Cadmium	0.005	Chromium	0.1	Copper	1.3	Cyanide (as free Cyanide)	.2	Fluoride	4.0	Lead	zero	Mercury	0.002	Nitrate	10 (as Nitrogen).	Nitrite	1 (as Nitrogen).	Total Nitrate + Nitrite	10 (as Nitrogen).	Selenium	0.05	Thallium	.0005

1 This value for arsenic is effective January 23, 2006. Until then, there is no MCLG.

[50 FR 47155, Nov. 14, 1985, as amended at 52 FR 20674, June 2, 1987; 56 FR 3593, Jan. 30, 1991; 56 FR 26548, June 7, 1991; 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 60 FR 33932, June 29, 1995; 66 FR 7063, Jan. 22, 2001]

§ 141.52 - Maximum contaminant level goals for microbiological contaminants.

(a) MCLGs for the following contaminants are as indicated:

Contaminant	MCLG	(1) Giardia lamblia	zero	(2) Viruses	zero	(3) Legionella	zero	(4) Total coliforms (including fecal)	zero	coliforms and Escherichia coli		(5) Cryptosporidium	zero	(6) Escherichia coli (E. coli)	zero

(b) The MCLG identified in paragraph (a)(4) of this section is applicable until March 31, 2016. The MCLG identified in paragraph (a)(6) of this section is applicable beginning April 1, 2016.

[78 FR 10347, Feb. 13, 2013]

§ 141.53 - Maximum contaminant level goals for disinfection byproducts.

MCLGs for the following disinfection byproducts are as indicated:

Disinfection byproduct	MCLG (mg/L)	Bromodichloromethane	zero	Bromoform	zero	Bromate	zero	Chlorite	0.8	Chloroform	0.07	Dibromochloromethane	0.06	Dichloroacetic acid	zero	Monochloroacetic acid	0.07	Trichloroacetic acid	0.02

[63 FR 69465, Dec. 16, 1998, as amended at 65 FR 34405, May 30, 2000; 71 FR 478, Jan. 4, 2006]

§ 141.54 - Maximum residual disinfectant level goals for disinfectants.

MRDLGs for disinfectants are as follows:

Disinfectant residual	MRDLG(mg/L)	Chlorine	4 (as Cl 2).	Chloramines	4 (as Cl 2).	Chlorine dioxide	0.8 (as ClO2)

[63 FR 69465, Dec. 16, 1998]

§ 141.55 - Maximum contaminant level goals for radionuclides.

MCLGs for radionuclides are as indicated in the following table:

Contaminant	MCLG	1. Combined radium-226 and radium-228	Zero.	2. Gross alpha particle activity (excluding radon and uranium)	Zero.	3. Beta particle and photon radioactivity	Zero.	4. Uranium	Zero.

[65 FR 76748, Dec. 7, 2000]