In accordance with the provisions of the Administrative Procedure Act, (R.S. 49:950, et seq.), the state health officer acting through the Department of Health, Office of Public Health (LDH-OPH), proposes to promulgate a rule to amend Part XII (Water Supplies) of Title 51 (Public Health?Sanitary Code) of the Louisiana Administrative Code (LAC). This action is being taken pursuant to the rulemaking authority granted by R.S. 40:4 and 40:5. The proposed rule is required by the United States Environmental Protection Agency (USEPA) in order that the Louisiana Department of Health, Office of Public Health (LDH-OPH) can maintain primacy (primary enforcement authority) over the regulation of public water systems in Louisiana. Particularly, this action is required under 40 CFR Part 142 (National Primary Drinking Water Regulations - Implementation) which was promulgated by the USEPA under the authority of the federal Safe Drinking Water Act (42 USC 300f, et seq.). Failure to adopt this proposed rule may cause the USEPA to withdraw its primacy delegation to LDH-OPH (with loss of federal grant funds) and/or may authorize USEPA to more easily take direct enforcement actions against non-complying public water systems located in Louisiana.