State primary enforcement responsibility

has adopted drinking water regulations that are no less stringent than the national primary drinking water regulations promulgated by the Administrator under subsections (a) and (b) of section 300g–1 of this title not later than 2 years after the date on which the regulations are promulgated by the Administrator, except that the Administrator may provide for an extension of not more than 2 years if, after submission and review of appropriate, adequate documentation from the State, the Administrator determines that the extension is necessary and justified;

( July 1, 1944, ch. 373 , title XIV, § 1413, as added Pub. L. 93–523, § 2(a) , Dec. 16, 1974 , 88 Stat. 1665 ; amended Pub. L. 99–339, title I, § 101(c)(2) , June 19, 1986 , 100 Stat. 646 ; Pub. L. 104–182, title I , §§ 112, 113(b), Aug. 6, 1996 , 110 Stat. 1633 , 1635; Pub. L. 115–270, title II, § 2010(b) , Oct. 23, 2018 , 132 Stat. 3848 .)