Replaces everything after the enacting clause with the provisions of the introduced bill with the following changes. Directs the Illinois Environmental Protection Agency to conduct statewide sampling of certain community water supplies for the presence of 1,4-Dioxane (rather than directs the Agency to propose, and the Pollution Control Board to adopt, rules establishing State-only maximum contaminant levels for likely or known carcinogens found in public drinking water systems). Provides that within one year of the promulgation by the United States Environmental Protection Agency (USEPA) of regulations or amendments establishing maximum contaminant levels (MCLs) for any PFAS, the Board shall adopt rules which are identical in substance to such federal regulations or amendments. Provides that the Agency shall, by June 30, 2026, conduct sampling of the Illinois community water supplies previously sampled by the Agency for 1,4-Dioxane from the years 2013 through 2015 (rather than the Agency shall conduct an initial study on primary drinking water standards and, by no later than June 30, 2025, present its findings to the General Assembly for the purpose of implementing a State-only MCL for carcinogens and toxic chemicals that are likely to pose a substantial health hazard). Provides that if the results of such sampling detect drinking water levels of 1,4-Dioxane in excess of the USEPA Health Reference Level of 35 micrograms per liter, the Agency shall (rather than the Agency shall, with no prefatory condition), within 2 years after June 30, 2026 (rather than 2025), take all actions needed to obtain expertise to propose rules to establish a State-only MCL for 1,4-Dioxane (rather than for carcinogens and toxic chemicals likely to pose a substantial health hazard). Provides that, by no later than June 30, 2029, the Agency shall propose, and, by no later than June 30, 2030, the Board shall adopt, amendments to the Board rules to establish a State-only MCL for 1,4-Dioxane (rather than no later than June 30, 2029, the Agency shall propose, and, by no later than June 30, 2030, the Board shall adopt, amendments to the Board rules that establish State-only MCLs for carcinogens and toxic chemicals that are likely to pose a substantial health hazard, with certain requirements). Removes provisions that the Agency and Board annually review relevant science and law for rulemaking and related purposes. Provides that the Agency shall, at least annually, convene a stakeholder group to review a subset of chemicals that are likely to pose a substantial health hazard to residents of the state, for the purpose of proposing or revising a State-only MCL for those chemicals.