[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: 40CFR131.3]

[Page 368-369]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 131--WATER QUALITY STANDARDS--Table of Contents
 
                      Subpart A--General Provisions
 
Sec. 131.3  Definitions.

    (a) The Act means the Clean Water Act (Pub. L. 92-500, as amended 
(33 U.S.C. 1251 et seq.)).
    (b) Criteria are elements of State water quality standards, 
expressed as constituent concentrations, levels, or narrative 
statements, representing a quality of water that supports a particular 
use. When criteria are met, water quality will generally protect the 
designated use.
    (c) Section 304(a) criteria are developed by EPA under authority of 
section 304(a) of the Act based on the latest scientific information on 
the relationship that the effect of a constituent concentration has on 
particular aquatic species and/or human health. This information is 
issued periodically to the States as guidance for use in developing 
criteria.
    (d) Toxic pollutants are those pollutants listed by the 
Administrator under section 307(a) of the Act.
    (e) Existing uses are those uses actually attained in the water body 
on or after November 28, 1975, whether or not they are included in the 
water quality standards.
    (f) Designated uses are those uses specified in water quality 
standards for each water body or segment whether or not they are being 
attained.
    (g) Use attainability analysis is a structured scientific assessment 
of the factors affecting the attainment of the use which may include 
physical, chemical, biological, and economic factors as described in 
Sec. 131.10(g).
    (h) Water quality limited segment means any segment where it is 
known that water quality does not meet applicable water quality 
standards, and/or is not expected to meet applicable water quality 
standards, even after the application of the technology-bases effluent

[[Page 369]]

limitations required by sections 301(b) and 306 of the Act.
    (i) Water quality standards are provisions of State or Federal law 
which consist of a designated use or uses for the waters of the United 
States and water quality criteria for such waters based upon such uses. 
Water quality standards are to protect the public health or welfare, 
enhance the quality of water and serve the purposes of the Act.
    (j) States include: The 50 States, the District of Columbia, Guam, 
the Commonwealth of Puerto Rico, Virgin Islands, American Samoa, the 
Trust Territory of the Pacific Islands, the Commonwealth of the Northern 
Mariana Islands, and Indian Tribes that EPA determines to be eligible 
for purposes of water quality standards program.
    (k) Federal Indian Reservation, Indian Reservation, or Reservation 
means all land within the limits of any Indian reservation under the 
jurisdiction of the United States Government, notwithstanding the 
issuance of any patent, and including rights-of-way running through the 
reservation.''
    (l) Indian Tribe or Tribe means any Indian Tribe, band, group, or 
community recognized by the Secretary of the Interior and exercising 
governmental authority over a Federal Indian reservation.

[48 FR 51405, Nov. 8, 1983, as amended at 56 FR 64893, Dec. 12, 1991; 59 
FR 64344, Dec. 14, 1994]