Mississippi Code Title 41. Public Health § 41-26-6

(1) The board may adopt rules and regulations governing public water systems, but those rules and regulations shall, except as expressly required by law, be no more stringent or extensive in scope, coverage and effect than regulations promulgated by the United States Environmental Protection Agency.

(2) If federal regulations do not provide a standard, criteria or guidance addressing public water systems, the board may promulgate rules and regulations to address these matters when the board determines that the rules and regulations are necessary to protect the public health and welfare.

(3) Nothing in this section shall prohibit the director by order or in the approval of plans for construction or changes from placing additional requirements on a public water system on a case by case basis in order to provide for the quantity and quality of drinking water or to protect the public health and welfare.