[Code of Federal Regulations]
[Title 40, Volume 19]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR131.11]

[Page 375]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 131--WATER QUALITY STANDARDS--Table of Contents
 
           Subpart B--Establishment of Water Quality Standards
 
Sec. 131.11  Criteria.

    (a) Inclusion of pollutants: (1) States must adopt those water 
quality criteria that protect the designated use. Such criteria must be 
based on sound scientific rationale and must contain sufficient 
parameters or constituents to protect the designated use. For waters 
with multiple use designations, the criteria shall support the most 
sensitive use.
    (2) Toxic pollutants. States must review water quality data and 
information on discharges to identify specific water bodies where toxic 
pollutants may be adversely affecting water quality or the attainment of 
the designated water use or where the levels of toxic pollutants are at 
a level to warrant concern and must adopt criteria for such toxic 
pollutants applicable to the water body sufficient to protect the 
designated use. Where a State adopts narrative criteria for toxic 
pollutants to protect designated uses, the State must provide 
information identifying the method by which the State intends to 
regulate point source discharges of toxic pollutants on water quality 
limited segments based on such narrative criteria. Such information may 
be included as part of the standards or may be included in documents 
generated by the State in response to the Water Quality Planning and 
Management Regulations (40 CFR part 35).
    (b) Form of criteria: In establishing criteria, States should:
    (1) Establish numerical values based on:
    (i) 304(a) Guidance; or
    (ii) 304(a) Guidance modified to reflect site-specific conditions; 
or
    (iii) Other scientifically defensible methods;
    (2) Establish narrative criteria or criteria based upon 
biomonitoring methods where numerical criteria cannot be established or 
to supplement numerical criteria.