Alaska Admin. Code tit. 18, § 80.300 – Maximum contaminant levels (MCLs)

(a) General requirement. Subject to a variance issued under 18 AAC 80.370, a variance issued under 18 AAC 80.371, or an exemption granted under 18 AAC 80.375, the owner or operator of a public water system may not cause or allow the use of water from that system for human consumption if the water contains, or has a significant potential for containing
1. (1) a contaminant in a concentration that exceeds a primary maximum contaminant level (MCL) set under (b) of this section; or
2. (2) a contaminant other than one described in (1) of this subsection, if the department determines that the concentration of that contaminant is high enough to make the water a hazard to human health.
(b) Primary MCLs.
1. (1) for inorganic chemical contaminants, the MCLs set out in 40 C.F.R. 141.62(b), adopted by reference in 18 AAC 80.010(a);
2. (2) for organic chemical contaminants that are
  1. (A) synthetic organic chemicals, the MCLs set out in 40 C.F.R. 141.61(c), adopted by reference in 18 AAC 80.010(a);
  2. (B) volatile organic chemicals, the MCLs set out in 40 C.F.R. 141.61(a), adopted by reference in 18 AAC 80.010(a);
  3. (C) disinfection byproducts, the MCLs set out in 40 C.F.R. 141.64(a), adopted by reference in 18 AAC 80.010(a);
3. (3) for turbidity, for a community water system, non-transient non-community water system, or transient non-community water system that uses a surface water source or a GWUDISW source and that meets the criteria for avoiding filtration under 40 C.F.R. 141.71, adopted by reference in 18 AAC 80.010(a), and under 18 AAC 80.620: the MCL as set out in 40 C.F.R. 141.13, adopted by reference in 18 AAC 80.010(a); if the system does not meet the criteria for avoiding filtration, the system must meet the applicable treatment technique requirements for turbidity under 18 AAC 80.303 instead of MCL requirements
4. (4) for Escherichia coli bacteria, the MCL as set out in 40 C.F.R. 141.63(c) and (d), adopted by reference in 18 AAC 80.010(a);
5. (5) for radionuclides, the MCL as set out in 40 C.F.R. 141.66, adopted by reference in 18 AAC 80.010(a).
(c) Secondary MCLs. The secondary MCLs for a public water system are set out in 40 C.F.R. 143.3, adopted by reference in 18 AAC 80.010(a). The department will require a public water system to meet the secondary MCLs if the department determines that public health is threatened or that exceeding a secondary MCL is not in the public interest.
(d) Repealed 4/24/2009.

(Eff. 10/1/99, Register 151; am 9/28/2001, Register 159; am 1/11/2004, Register 169; am 5/2/2004, Register 170; am 1/11/2006, Register 177; am 11/9/2006, Register 180; am 4/24/2009, Register 190; am 2/11/2017, Register 221; am 5/3/2019, Register 230)

Authority: AS 46.03.020, AS 46.03.050, AS 46.03.710, AS 46.03.720