Mixing Zone Compilation

The mixing zone information provided here was previously published in various handbooks, memos, and other EPA documents. This information can be used by states when revising their mixing zone provisions in their water quality standards, or when implementing them in NPDES permits. Stakeholders may also use it when considering mixing zone policies and implementation procedures in their jurisdictions.

The full compilation is available in hard copy. You can order the document EPA-823-R-06-003 from the National Service Center for Environmental Publications (1-800-490-9198).


The discussions in the documents collected in this Compilation are intended solely as guidance. The statutory provisions and EPA regulations described in this compilation contain legally binding requirements. This document (or the documents referenced herein) are not a regulations, nor do they change or substitute for those statutory provisions and regulations. Thus, this document or the documents collected here do not impose legally binding requirements on EPA, states, authorized tribes, territories, or the regulated community. This Compilation does not confer legal rights or impose legal obligations upon any member of the public.

While EPA has made every effort to ensure the accuracy of the discussion in this Compilation, the obligations of the regulated community are determined by statutes, regulations, or other legally binding requirements. In the event of a conflict between the discussion in this Compilation and any statute or regulation, this Compilation would not be controlling.

The general description provided here may not apply to every circumstance. Interested parties are free to raise questions and objections about the substance of this guidance and the appropriateness of its application to a particular situation. EPA and other decision-makers retain the discretion to adopt approaches on a case-by-case basis that differ from those described in this guidance where appropriate.

Mention of trade names or commercial products does not constitute endorsement or recommendation for their use.

This is a living document and may be revised periodically without public notice. EPA welcomes public input on this document at any time.

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