The Florida Department of Environmental Protection (department) is amending Chapter 62-303, F.A.C., to update the listing methodology for assessing human health-based water quality criteria as part of the process to identify impaired surface waterbodies. This rulemaking is being conducted in conjunction with rulemaking to revise the human health-based criteria in Chapter 62-302, F.A.C. (noticed under a separate rulemaking notice). Additionally, in accordance with the requirements of paragraph 403.061(29)(b) and paragraphs 403.861(21)(a) and (b), Florida Statutes, enacted under Chapter 2016-01, Laws of Florida, the department is proposing to establish a new sub-classification of surface waters (Class I-B, Treated Potable Water Supplies), which will require minor revisions in Chapter 62-303, F.A.C. Specifically, the department plans to revise a number of rules in Chapter 62-303, F.A.C., to clarify that Class I waters include both “Class I-A” (existing Class I waters) and “Class I-B” (Treated Potable Water Supply waters).