Clean Water Act

The Total Maximum Daily Load (TMDL) program is intended to ensure that the nation's waters meet water quality standards. GAO reports on its recent analysis of economic and compliance issues associated with two recently proposed rulemakings by the Environmental Protection Agency (EPA) intended to strengthen its TMDL program. TMDLs are used to restore water quality by identifying how much pollution a body of water can receive and still meet its standards. The amount of pollution entering the water is then reduced to that level.

GAO noted that: (1) limitations with EPA's economic analyses of the proposed regulations for the Total Maximum Daily Load (TMDL) and the National Pollutant Discharge Elimination System (NPDES) programs raise questions about their reasonableness and about the determinations that EPA has based on them; (2) of particular consequence, the outcomes of the analyses were heavily influenced by a number of key assumptions; (3) among the most important of these assumptions was that states are essentially in full compliance with current regulations, or will be as a result of existing statutory and regulatory requirements; (4) therefore, EPA included in its estimate only the costs that would result from the new requirements in the proposed regulations and not the costs of doing TMDLs generally; (5) however, compliance with existing TMDL regulations has been problematic, and future compliance in the absence of the proposed regulation is uncertain; (6) GAO found similar uncertainties with key baseline assumptions that affect the cost estimates associated with the proposed NPDES regulation; (7) another key limitation of the analyses was that they did not sufficiently recognize that the key water quality data available to EPA to identify the number of waters not meeting standards (and, hence, the number of TMDLs that will be needed) are incomplete, inconsistently collected by states, and sometimes based on outdated and unconfirmed sources; (8) as a result of these limitations, EPA's cost estimates are subject to substantial uncertainty; (9) under these circumstances, it would have been appropriate for EPA to assess the effect of different assumptions on the agency's cost estimates; (10) had it done so, the agency would likely have produced a range of possible costs exceeding those included in its analyses; (11) given the uncertainties surrounding EPA's cost estimates, GAO disagrees with EPA that the agency's analyses adequately supported its determinations under the Unfunded Mandates Reform Act of 1995 that more detailed analyses of costs, benefits, and alternatives were not needed for either of the proposed regulations; and (12) in the case of the requirements for additional analyses under the Regulatory Flexibility Act, case law supports EPA's determination that because its proposed revisions to both regulations do not directly regulate small entities, additional analyses were not required.