United States
Environmental Protection
Agency
Office of Water
Regulations and Standards
Washington, DC 20460
December 1983
Water
vvEPA
Questions & Answers on:
Water Quality Standards
OOOR83102
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WATER QUALITY STANDARDS
Questions and Answers
1. UNDER WHAT SECTION OF THE CLEAN WATER ACT (CWA) DOES THE WATER
QUALITY STANDARD PROGRAM OPERATE?
Section 303 of the CWA (33 U.S.C. 1313(c)). The inplementing
Regulation nay be found at 48 FR 51400, November 8, 1983.
2. WHAT IS A WATER QUALITY STANDARD?
A water quality standard is a rule or law conprised of the use or
uses to be made of the water body or segment and the water quality
criteria necessary to protect that use or uses. (See questions 11
and 15). Essentially all of these rules are established by the
States, although occasionally a Federal rule will supersede part
of a State's rule. Water quality standards are to protect the
public health or welfare, enhance the quality of the water and
serve the purposes of the Act.
3. WHAT IS THE PURPOSE OF A WATER QUALITY STANDARD?
Standards serve the dual purposes of establishing the water
quality goals for a specific water body and serve as the
regulatory basis for the establishment of water-quality-based
treatment controls and strategies beyond the technology-based
levels of treatment required by Sections 301(b) and 306 of the
CWA.
4. WHAT ARE THE IMPROVEMENTS IN THE REGULATION THAT WILL BE EMPHASIZED
IN THE MANAGEMENT OF THE STANDARDS PROGRAM?
- Emphasis on the goals of the Act; i.e., "Water Quality should,
wherever attainable, provide for the protection and propagation
of fish, shellfish, and wildlife and recreation in and on the
water" (Section 101(a)(2)).
- Increased emphasis on the control of toxic pollutants.
- Inclusion of a provision for mandatory upgrading of water
quality standards.
- Clarification of provisions for changing water quality
standards.
- Clarification and expansion of State/EPA roles.
- Refinement of the forms of water quality criteria and their
application.
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- Clarification and expansion of the antidegradation policy.,
- Clarification of the dual role of standards in establishing
water quality goals and providing a regulatory basis for
treatment beyond that required by §301(b) and §306.
5. DOES THE INCREASED ATTENTION TO THE WATER QUALITY-BASED APPROACH
MEAN EPA IS ABANDONING TECHNOLOGY-BASED CONTROLS?
Definitely not. Nothing in the proposed water quality standards
regulation amends or modifies in any way the technology-based
requirements of the Clean Water Act applicable to municipalities
or industries. The water-quality based approach will enable
States to provide adequate water quality protection beyond what
will be achieved through technology-based control.
6. DOES THE EMPHASIS ON STATE INVOLVEMENT MEAN THE AGENCY IS REDUCING
ITS INVOLVEMENT IN THE REVIEW OF STATE-ADOPTED STANDARDS?
No. In fact, to properly implement the new program policies,
there needs to be increased active EPA regional participation with
the States beginning at the start of the revision process so that
the need to disapprove a State-adopted standard is reduced to an
absolute minimum.
The Regional Office must ensure, through cooperation with the
State, that the process and procedures a State will use to revise
standards will result in sufficient data to support a public
decision on standards. Regional Administrators, in their review
of State standards, are to assure that decisions on standards are
adequately supported by scientific and technical evidence. The
Administrator's responsibility to promulgate Federal standards is
not diminished in any way by the regulation.
7. WILL THE NEW POLICIES RESULT IN INCREASED DOWNGRADING OF STREAM
USES?
No. Increased stream "downgradings" are not anticipated because
the regulation specifies that designated uses cannot be removed if
the uses are existing (unless a use requiring more stringent
criteria is added), or if uses can be attained through technology
based controls or best management practices. Additionally, when a
State desires to change the designated uses of its waters such
that the uses of the water body do not include the uses specified
in the Act (i.e., the protection and propagation of fish,
shellfish, and wildlife and recreation in and on the water), the
State will have to demonstrate through a use attainability
analysis that these uses are not attainable based on physical,
chemical, biological or economic factors. This use attainability
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analysis is also required for future changes that the State may
make for a water body and for current use designations which do
not include the uses specified in the goals of the Act. Also, the
antidegradation policy provides special protection for high
quality waters and waters which constitute an outstanding national
resource.
8. WHAT IMPACT WILL THESE IMPROVEMENTS HAVE ON WATER QUALITY?
Water quality will be improved because attainable standards will
be set and realistic control programs will be put in place to
achieve those standards. Overall, since the standards are
expected to be more appropriate for a particular water body, EPA
expects to achieve identifiable water quality improvement. In
some cases, standards have been set at unattainable levels and
have not provided a realistic basis for treatment and control
programs.
9. TO WHAT WATERS DOES A WATER QUALITY STANDARD APPLY?
The waters of the United States. The term "navigable waters" was
changed in the Regulation to "waters of the United States" to
avoid confusion. The CWA defines "navigable waters" as "waters of
the United States", a broader class of waters than considered
"navigable" under some other statutes.
10. DO WATER QUALITY STANDARDS APPLY TO GROUND WATERS?
Ground water standards are not a requirement under the Clean Water
Act, although States can adopt standards under their own laws to
protect the ground waters of the State.
11. WHAT ARE THE USES OF A WATER BODY?
Section 303(c) of the CWA mentions several uses including: public
water supplies, protection and propagation of fish and wildlife,
recreation, agricultural and industrial water supplies and
navigation. While the statutory listing of uses is not a
limitation, EPA does not recognize waste transport as a beneficial
use.
12. HOW ARE USES ESTABLISHED?
.States have primary responsibility for establishing stream uses
through a periodic review process involving consultation with EPA
and public hearings which must occur at least once every three
years. Section 303(c) of the Act requires that standards "shall
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be established taking into consideration their use and value
for..." the uses named in question #11. Section 101(a)(2) of the
Act indicates that "wherever attainable" water quality standards
are to provide for the protection and propagation of fish,
shellfish and wildlife and to provide for recreation in and on the
water". States designate uses for a water body consistent with
the Act by analyzing the existing uses made of the water body and
the potential of the water body to attain particular uses based on
physical, chemical, biological and hydrological characteristics of
the water body. Where designated uses do not include those
specified in the goals of the Act, the State is required to
conduct a use attainability analysis. Where water quality
improvements result in new uses, States must revise their
standards to reflect these new uses. In establishing uses, States
must protect and maintain downstream standards.
13. HOW ARE USES FOR OUTSTANDING NATIONAL RESOURCE WATERS ESTABLISHED?
As with other uses, the States designate appropriate waters as
Outstanding National Resource Waters (ONRW). The selection is
based on the need to provide maintenance and protection to high
quality waters that constitute an outstanding national resource,
such as waters of national and State parks, wildlife refuges and
waters of exceptional recreational or ecological significance.
The States also establish the criteria that specifically protect
the characteristics that make the water an ONRW. Ordinarily most
people believe this category protects the highest quality waters;
and that is the primary intent. The ONRW category also offers a
means to provide special protection to waters of "ecological
significance". These are water bodies which are important,
unique, or sensitive ecologically, but whose water quality as
measured by traditional parameters (dissolved oxygen, pH, etc.)
may not be particularly high or whose character cannot be
adequately described by these parameters. Such unique waters
might include swamps, hot springs, etc.
14. DO ALL STATES HAVE THE SAME USES FOR THEIR WATERS?
Each State has its own classification system. However, the same
basic uses of support and propagation of aquatic life and
recreation in and on the water are used by all States with
variations of different uses for different waters. The States may
differentiate the types of uses to be protected, such as coldwater
or warmwater fisheries, or specific species that are to be
protected, such as trout or bass. They may also designate special
uses to protect particularly sensitive or valuable water bodies.
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15. WHAT ARE WATER QUALITY CRITERIA?
Criteria are elements of State water quality standards expressed
as constituent concentrations or levels, or narrative statements,
that represent a quality of water that supports a particular use.
When criteria are properly selected and met, it is presumed that
water quality will protect the designated use.
16. HOW ARE CRITERIA ESTABLISHED?
Criteria may be established by adopting or modifying EPA's §304(a)
guidance, employing bioassay or biological criteria, if
appropriate, or using narrative descriptions where numerical
values cannot be established. EPA recommends establishing
numerical values wherever practical. Site-specific criteria can
also be developed in cases where background water quality
parameters or aquatic organisms differ from those used in the
laboratory to develop criteria. The procedures for development of
site-specific criteria are described in EPA's Water Quality
Standards Handbook.
17. WHAT IS THE DIFFERENCE BETWEEN SECTION 304(a) CRITERIA GUIDANCE AND
CRITERIA INCLUDED IN STATE WATER QUALITY STANDARDS?
Section 304(a) criteria guidance is published by EPA based on the
latest scientific information available on the effect of a
pollutant on human health and aquatic life. The section 304(a)
criteria are guidance and have no regulatory impact. Criteria
adopted by States in their water quality standards are enforceable
requirements that are used to regulate pollutants under the Clean
Water Act. The most recent publications of criteria guidance by
EPA include: Quality Criteria for Water. July, 1976, and Water
Quality Criteria Documents, NovemEer 28, 1980, 45 FR 79318.
18. FOR WHAT POLLUTANTS OR OTHER WATER QUALITY CONSTITUENTS DO STATES
GENERALLY SET CRITERIA IN THEIR WATER QUALITY STANDARDS?
All States currently have criteria in their water quality
standards for: dissolved oxygen, pH, fecal coliform bacteria,
temperature, toxic substances and aesthetic qualities. Previous
EPA guidance recommended these constituents as a minimum.
19. ARE NUMERICAL CRITERIA FOR TOXIC POLLUTANTS REQUIRED TO BE INCLUDED
IN STATE WATER QUALITY STANDARDS?
States may use either numerical or narrative criteria in their
standards. Although numeric criteria are simpler and easier to
apply, there are many cases where conditions dictate the use of
narrative criteria.
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20. HOW DO STATES DETERMINE WHETHER TO USE NUMERICAL OR NARRATIVE
CRITERIA?
States are to review their water quality data and information on
discharges to identify specific water bodies where toxic
pollutants may be adversely impacting water quality or the
designated uses, or where the level of a toxic pollutant in the
water is at a level to warrant concern. States are expected to
conduct such reviews beginning with an in-depth analysis of water
bodies with known toxic pollutant problems. States are to adopt
numerical or narrative criteria for those toxic pollutants of
concern. Numerical criteria are appropriate where a few specific
pollutants have been identified as the concern, or where human
health rather than aquatic life is the controlling factor.
Where the effluent or ambient conditions are complex, due to
multiple dischargers or multiple pollutants, site-specific toxic
pollutant limits may be legally supported on narrative criteria
such as the "free from" statements used in virtually all State
standards.
21. HOW ARE WATER QUALITY STANDARDS ESTABLISHED?
The CWA requires States to hold public hearings, at least once
every three years, for the purpose of reviewing applicable water
quality standards, and to modify and adopt new or revised
standards where appropriate. After opportunity for public comment,
States are to adopt the water quality standards pursuant to State
law.
22. DO ALL STATES HAVE WATER QUALITY STANDARDS?
Yes. All 50 States, the District of Columbia, the Commonwealth of
Puerto Rico, Guam, American Samoa, Virgin Islands, the Trust
Territory of the Pacific Islands, and the Commonwealth of the
Northern Mariana Islands have adopted water quality standards.
23. HOW LONG DOES IT TAKE FOR STATES TO REVIEW, REVISE AND ADOPT WATER
QUALITY STANDARDS?
Each State has its own legal procedures for adopting water quality
standards. Therefore, the time varies depending upon the
complexity of the revision and the procedures that the individual
State must follow in adopting standards. In any event, the review
process must be completed within a three year period.
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24. TO WHOM IN EPA DO THE STATES SEND THEIR WATER QUALITY STANDARDS?
States send their officially adopted water quality standards to
the appropriate Regional Administrator.
25. WHAT DOES THE REGIONAL ADMINISTRATOR DO WITH A STATE'S WATER
QUALITY STANDARDS?
The Regional Administrator reviews the State's water quality
standards to determine compliance with the requirements of the
Clean Water Act, and may approve or disapprove State water quality
standards based on that determination.
26. WHY IS EPA INVOLVED IN THE WATER QUALITY STANDARDS PROGRAM?
The CWA requires States to submit their new or revised water
quality standards to EPA. EPA reviews the scientific and
technical analyses to ascertain that a State's standards meet the
requirements of the Act and that one State's standards do not
interfere with the attainment of standards in another State's
waters.
27. WHAT HAPPENS IF THE STATE'S WATER QUALITY STANDARDS DO NOT MEET
THE REQUIREMENTS OF THE ACT?
If the Regional Administrator determines that the State water
quality standards do not meet the requirements of the Act, the
Regional Administrator is to specify the changes necessary for the
State's water quality standards to meet the requirements of the
Act. If the changes are not made, the Administrator of the
Environmental Protection Agency is to begin the promulgation of a
Federal regulation setting forth a new or revised water quality
standard for the waters involved. The Administrator also has
authority to promulgate Federal standards in any case where a new
or revised standard is necessary to meet the requirements of the
Act. In practice, Federal promulgation has involved only a very
small part of the standards effort, usually the promulgation of
uses or criteria on one or a few water segments.
28. HAS EPA EVER PROMULGATED WATER QUALITY STANDARDS?
EPA promulgated Federal standards for the States of Kentucky,
Arizona, Nebraska, Mississippi, Alabama, North Carolina and Ohio.
However, the promulgations for Alabama, Kentucky, Nebraska, North
Carolina and Ohio have been withdrawn.
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29. WHY WOULD EPA PROMULGATE FEDERAL STANDARDS AND THEN WITHDRAW THE
PROMULGATION?
EPA withdrew the promulgation of Federal standards where the State
subsequently adopted State standards which met the requirements of
the Act.
30. IF EPA PROMULGATES FEDERAL WATER QUALITY STANDARDS, IS EPA SUBJECT
TO THE SAME REQUIREMENTS AS THE STATES?
Generally. EPA is subject to the same substantive requirements in
promulgating standards as States are in adopting standards.
Procedural requirements may be different.
31. WHERE CAN ONE FIND INFORMATION ON THE WATER QUALITY STANDARDS OF A
PARTICULAR STATE?
Information on State water quality standards may be obtained from
the State water pollution control agency, from the Environmental
Protection Agency through its Regional Offices, or from its
Washington, D.C. headquarters. Secondary references include
proprietary publications such as those of the Bureau of National
Affairs.
32. HOW DO STATES USE WATER QUALITY STANDARDS?
Water quality standards are the foundation of a State's water
quality management program. Water quality standards establish
water quality goals and requirements for specific water bodies;
serve as the basis for regulating and enforcing municipal and
industrial pollutants under the Clean Water Act; drive the
planning and implementation of water quality-based pollution
control programs; and provide a measurement of the effectiveness
of pollution control programs through attainment of water quality
standards.
33. WHAT IS DONE TO ENSURE THAT STANDARDS ARE MET?
Under the National Pollutant Discharge Elimination System (NPDES),
permits are issued to municipal and industrial dischargers to
ensure that pollutant discharges do not violate water quality
standards. State and Federal monitoring, inspection, and
enforcement programs ensure compliance with standards and
permits.
34. HOW ARE WATER QUALITY STANDARDS ENFORCED?
The primary mechanism for enforcing water quality standards is
through translation into water quality-based permit limitations,
Permits are issued under provisions of the National Pollutant
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Discharge Elimination System (i.e. NPDES Permits). States also
can enforce water quality standards directly. There is no direct
Federal enforcement mechanism of water quality standards provided
in the CWA.
35. WHO SELECTS THE WATERS TO BE REVIEWED?
States, in consultation with EPA, select the water bodies where
water quality standards are to be reviewed in depth. This
decision is based on the State 305 (b) Reports, the waters
identified under section 303 (d) of the Act, the construction grant
priority list and segments where major permits have expired. Any
water body with standards not consistent with the Section
101 (a) (2) goals of the Act must be reexamined every three years.
36. AFTER DECEMBER, 1984, MUST ALL WATER QUALITY STANDARDS BE REVIEWED
IN A STATE PRIOR TO RECEIVING A CONSTRUCTION GRANT?
No. Section 24 of the "Municipal Wastewater Treatment
Construction Grant Amendments of 1981" (33 U.S.C. 1313 (a)) is
intended to ensure that the water quality standards have been
reviewed for the water bodies or segments which receive discharges
from applicants for construction grants.
37. SINCE ALL STATES HAVE ADOPTED WATER QUALITY STANDARDS, WHY REVIEW
AND REVISE THE STANDARDS?
The law requires that States hold a public hearing to review, and
if appropriate/ revise their water quality standards at least once
every three years. In addition, States may wish to review their
standards because many standards were initially set for the
protection and propagation of aquatic life and for recreation in
and on the water without adequate data and information as to
whether these uses were' attainable. There may be physical factors
including flow, obstructions, or high or low tenperatures
precluding an aquatic life use, or there may be irreversible
natural or man- induced pollutant problems precluding a. use. Other
reasons for reviewing water quality standards include additional
scientific knowledge and improvements in technology which become
available, as well as changes which occur in the environment. The
States also have the responsibility to ascertain that their
standards fulfill the requirements of the revised water quality
standards regulation (40 CFR Part 131), the purpose of which is to
require that States establish standards that reflect the goals of
the CWA.
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38. WHAT ANALYSES ARE CONDUCTED TO DETERMINE WHETHER A WATER QUALITY
STANDARD IS APPROPRIATE?
Analyses are made of the water body to determine whether impaired
uses are attainable based on physical, chemical, biological or
economic factors, and whether the criteria are appropriately based
on site-specific water quality characteristics (temperature, pH,
etc.) or adaptation of local species.
39. WHAT DOES A "USE ATTAINABILITY ANALYSIS" CONSIST OF?
A use attainability analysis is a multi-step assessment of the
physical, chemical, biological and economic factors affecting the
attainment of a use. It includes a water body survey and
assessment, a wasteload allocation, and an economic analysis, if
appropriate.
40. WHAT QUESTIONS ARE STATES TRYING TO ANSWER IN CONDUCTING A USE
ATTAINABILITY ANALYSIS?
A use attainability analysis assists States in answering; (1)
What is the use to be protected? (2) To what extent does pollution
(as opposed to physical factors) contribute to the impairment of
the use? (3) What is the level of point source control necessary
to restore or enhance the use? (4) What is the level of nonpoint
source control necessary to restore or enhance the use.
41. HOW WILL THE USE ATTAINABILITY ANALYSIS ASSIST A STATE IN
DETERMINING APPROPRIATE USES OF A WATER BODY?
By conducting a use attainability analysis, States will be able
to:
a) designate uses for a water body which will not have all uses
that are included in Section 101(a)(1) of the Act (goals), (b)
maintain uses for a water body which do not include all of the
uses in Section 101(a)(2), (c) remove a use included in Section
10l(a)(2) or (d) modify a use included in Section 101(a)(2).
A State need only conduct a use attainability analysis once for a
given water body and set of uses. States also have the option of
conducting a use attainability analysis even when not required to,
if they believe that there will be questions as to whether the
protection and propagation of fish, shellfish and wildlife and
recreation in and on the water is, in fact, attainable.
42. WHAT ARE THE CIRCUMSTANCES UNDER WHICH A STATE MAY CHANGE A USE?
States may modify or reclassify uses if attaining the use is not
feasible because:
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(1) naturally occurring pollutant concentrations prevent the
attainment of the use, (2) natural, ephemeral, intermittent or low
flow conditions or water levels prevent the attainment of the use,
(3) human caused conditions or sources of pollution prevent the
attainment of the use and cannot be remedied or would cause more
environmental damage to correct than to leave in place, (4) dams,
diversions, or other types of hydrologic modifications preclude
the attainment of the use, (5) physical conditions related to the
natural features of the water body, and unrelated to quality that
preclude attainment of aquatic life protection uses and (6)
controls more stringent than those required by Sections 301(b) and
306 of the Act would result in substantial and widespread economic
and social impact.
43. WHEN MUST A STATE CONDUCT A USE ATTAINABILITY ANALYSIS?
A State must conduct a use attainability analysis whenever (1)
the State designates or has designated uses that do not include
the uses specified in Section 101(a)(2) of the Act, or (2) the
State wishes to remove a designated use that is specified in
Section 101(a) (2) of the Act or to adopt subcategories which
require less stringent criteria. A State is not required to
conduct a use attainability analysis when it designates uses which
include those specified in Section 101(a)(2) of the Act.
44. WHEN MAY STATES NOT RECLASSIFY A USE TO ONE REQUIRING LESS
STRINGENT CRITERIA?
Uses may not be changed to a less restrictive one if: they are
existing uses, as defined in Section 131.3, unless (1) a use
requiring more stringent criteria is added, or, (2) such uses will
be attained by implementing effluent limits required under
Sections 301(b) and 306 of the Act and by implementing
cost-effective and reasonable best management practices for
nonpoint source control. In addition, uses may not be modified or
changed if the revision would result in the impairment of
downstream standards.
45. WHAT IS MEANT BY THE STATEMENT, ONCE A USE IS ATTAINED IT MUST BE
MAINTAINED?
Each state must include in its water quality standards a Statewide
antidegradation policy statement that uses attained are
maintained. This policy is necessary to protect the Nation's
substantial investment in water pollution control. It also
affirms the philosophical commitment embodied in the CWA to
protect the Nation's waters.
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46. HOW HAS THE ANTIDEGRADATION POLICY CHANGED?
The antidegradation policy included in the regulation has not
fundamentally changed. The antidegradation policy represents a
three tiered approach to maintaining and protecting various levels
of water quality and uses. At its base, the existing uses of a
water segment and the quality level necessary to protect the uses
must be maintained. This establishes the absolute floor of water
quality. The second level provides protection of actual water
quality in segments where quality exceeds levels necessary to
support progagation of fish, shellfish, and wildlife and
recreation in and on the water (fishable/swimmable). In such
segments limited water quality degradation can be allowed after it
has been shown through a demonstration process, which includes
public participation, that quality will continue to support the
"fishable/swimmable" use. The third tier provides special
protection of waters for which the ordinary use classifications
may not suffice and are classified as "Outstanding National
Resource Waters" (ONRW). The thrust of this special protection is
viewed by most as protection for the highest quality wat€»rs of the
nation but such special protection can be applied to waters of
"ecological significance". These are water bodies which are
important, unique, or sensitive ecologically, and have quality
parameters that vary from the traditional parameters of dissolved
oxygen, pH, and etc,, (see question 13).
47. WHAT HAPPENS IF THERE ARE CONTINUING VIOLATIONS OF THE CRITERIA FOR
PARTICULAR POLLUTANTS BUT THE USES ARE ATTAINED, OR THERE ARE NO
VIOLATIONS IN THE CRITERIA BUT THE USES ARE IMPAIRED?
EPA is recommending that States develop site-specific criteria to
reflect local conditions. The laboratory-derived section 304(a)
criteria guidance, which most States use in their water quality
standards, may not accurately reflect the effect of a pollutant
because of local water quality characteristics such as
temperature, hardness, etc., or because local species have adapted
or are less or more sensitive than those used in the laboratory.
EPA has developed scientific procedures that States may use to
change, on a site-specific basis, the criteria included in their
standards to reflect actual instream conditions (see the Water
Quality Standards Handbook).
48. DOES SETTING SITE-SPECIFIC CRITERIA MEAN A STATE CAN HAVE DIFFERENT
CRITERIA FOR THE SAME POLLUTANTS EVEN THOUGH THE SAME USES MAY BE
DESIGNATED FOR DIFFERENT WATER BODIES?
Yes. The different physical, chemical and hydrological
characteristics of the water body may affect the impact of a
pollutant on the use to be protected.
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49. ARE STATES REQUIRED BY THE REGULATION TO CONDUCT USE ATTAINABILITY
ANALYSES, AS WELL AS DEVELOP SITE-SPECIFIC CRITERIA?
As indicated in question 43, States are required to conduct and
submit to EPA a use attainability analysis if the State (a) is
designating uses for the water body such that the water body will
not have all uses which are included in Section 101(a)(2) of the
Act, (b) maintaining uses for the water body which do not include
all of the uses in Section 101(a)(2) of the Act or (c) modifying a
use included in Section 101(a)(2) of the Act to require less
stringent criteria. States are not required to conduct and submit
to EPA a use attainability analysis if adding a use specified in
Section 101(a)(2) of the Act or a use requiring more stringent
criteria. States are not required to develop site-specific
criteria. In cases where the State believes that uses can be
maintained under criteria levels less stringent than those
recommended by the National Section 304(a) criteria, the States
may scientifically develop and establish such criteria.
Site-specific criteria development procedures are not needed in
all situations. Many of the procedures are expensive.
Site-specific criteria development appears most appropriate on
water quality limited water bodies where: (1) background water
quality parameters, such as pH, hardness, temperature, suspended
solids, etc., appear to differ significantly from the laboratory
water used in developing the Section 304(a) criteria; or (2) the
types of local aquatic organisms in the region differ
significantly from those actually tested in developing the Section
304(a) criteria.
The protocols for establishing site-specific criteria, as well as
the test cases illustrating use of the protocols, are included in
the Water Quality Standards Handbook.
50. IS IT POSSIBLE FOR OTHER STATE AGENCIES, LOCAL GOVERNMENTS AND THE
PUBLIC TO COMMENT ON OR DISAGREE WITH THE PROPOSED STATE WATER QUALITY
STANDARDS?
Yes. States are required by the CWA to hold public hearings on
any revisions to their water quality standards. The analyses that
are used as part of the State's determination to maintain, modify
or change a use or a criterion in the standard are to be made
available to the public prior to the public hearing. This
provides an opportunity for open debate of the analyses among
scientific peer groups and the public impacted by a water quality
standard revision. Additional information or perceptions brought
to the public hearing will assist the State rulemaking body to set
appropriate site-specific water quality standards. EPA will also
review the record of public hearings as part of its standards
review process.
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51. WHAT GUIDANCE WILL EPA PROVIDE TO STATES?
EPA will make available a Water Quality Standards Handbook that
contains a series of guidance documents that cover the technical
and administrative aspects of the water quality standards program.
Of particular interest are the guidance documents on: Setting
Site-Specific Criteria; Water Body Surveys and Assessments for
Conducting a Use Attainability Analysis.
52. HOW WILL THESE "GUIDANCE" DOCUMENTS BE USED BY EPA?
The purpose of the guidance documents is to make available to the
States a number of alternative methods, procedures and approaches
for setting site-specific criteria and conducting use
attainability analyses. States may and will likely use
alternative ways of analyzing their water quality standards than
those outlined in the Handbook. However, the approaches outlined
do provide a benchmark or a "guide" for States to use in
determining the information EPA believes is sufficient for its
review of any revisions to State water quality standards. States
are encouraged to consult early and frequently with EPA as
assessments and analyses are initiated and carried out. EPA is
concerned with assisting States in obtaining the data and
information needed for their water quality standards
decision-making process.
53. WHAT ARE THE "GENERAL POLICIES" DISCUSSED IN THE PROPOSED WATER
QUALITY STANDARDS REGULATION?
These are policies generally applicable to a State's water quality
standards program such as policies on mixing zones, variances and
low flow exemptions.
54. DO STATES HAVE TO ADOPT GENERAL POLICIES?
No. EPA leaves it up to the States to adopt statewide general
policies that provide an understanding of how their water quality
standards will be implemented.
55. ARE THE GENERAL POLICIES CONSIDERED TO BE PART OF A STATE'S WATER
QUALITY STANDARDS?
Yes. If adopted, the general policies must be submitted to EPA
for review.
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56. WHAT IS A "MIXING ZONE"?
A mixing zone is a limited area, serving as a zone of initial
dilution, in the immediate area of a point or nonpoint source of
pollution.
57. WHAT IS A "VARIANCE"?
As an alternative to downgrading standards, States may include a
variance as part of a water quality standard rather than change
the standard because the State believes that the standard
ultimately can be attained. By maintaining the standard rather
than changing it, the State will assure further progress is made
in improving water quality and attaining the standard. EPA can
approve State-adopted variances if, (1) the variance is included
as part of the water quality standard, (2) it is subject to the
same public review as other changes in water quality standards
and, (3) if the variance is granted based on a demonstration that
meeting the standard would cause substantial and widespread
economic and social impact. A variance may be granted to an
individual discharger. However, the determining factor is whether
the economic impact on the discharger is sufficient to have a
substantial and widespread impact on the affected community and
not just on the discharger. With the variance provision, NPDES
permits may be written such that reasonable progress is made
toward attaining the standard without violating Section 402(a)(1)
of the Act which states that NPDES permits must meet the
applicable water quality standards. The term "variance", if it is
used at all in a State's standards, is not always defined
consistently from State to State. Therefore, some State
"variance" policies and procedures may not be consistent with the
standards regulation but, for example, an "exception" policy might
be.
58. WHAT IS A FLOW EXEMPTION?
In setting permit limits for dischargers to comply with the water
quality standards, a wasteload allocation is performed based on a
specific lew flow of the stream. In extreme situations where the
flow drops below the flew used in the wasteload allocation, the
water quality standards may be violated. The low flow exemption
identifies the flow and circumstances where exemptions from
meeting the standard might be necessary. As an alternative to low
flow exemptions, States, on particular water segments, may adopt
seasonal water quality standards which could be met regardless of
low flow conditions. This might be appropriate for streams which
have a natural ephemeral or intermittent nature.
NOTE: This document is intended only to provide general information on
the water quality standards program to the public. It reflects the
regulatory provisions and implementing guidance but it does not
substitute for the detailed requirements and guidance provisions
contained in the regulation or the Water Quality Standards Handbook.
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