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Water Quality Standards Regulations: Montana

Presented below are water quality standards in effect for Clean Water Act (CWA) purposes for this state.

EPA is posting these standards as a convenience to users and has made a reasonable effort to assure their accuracy. Also, for each document listed under "State Standards in Effect for CWA Purposes", EPA has made a reasonable effort to identify parts of the standards that are disapproved or are otherwise not in effect for CWA purposes.

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State Standards in Effect for CWA Purposes

Montana's water quality standards are applicable to "waters of the State". In some limited instances, the definition adopted by Montana for "waters of the State" as part of its water quality standards may result in water quality standards that are more comprehensive than required under section 303(c) of the Clean Water Act and the implementing federal regulations. Specifically, Montana has adopted additional provisions related to groundwater that are outside the scope of the Clean Water Act and implementing federal regulations. EPA has included the State's water quality standards in their entirety here for context and as supplementary information for the reader.

Montana water quality standards apply to all waters within the State of Montana, with the exception of those waters that are within Indian Country, as defined in 18 U.S.C. Section 1151. EPA's approval of Montana's water quality standards was not intended as an action to approve or disapprove water quality standards applying to waters within Indian Country. EPA, or eligible Indian Tribes, as appropriate, will retain responsibilities for water quality standards within Indian Country.


Federally Proposed or Promulgated Standards

None at this time.

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