|(a) Contents of the Texas Surface Water Quality Standards.
(1) Section 307.1 of this title (relating to General
Policy Statement) contains the general standards policy of the commission.
(2) This section lists the major sections of the standards,
defines basin classification categories, describes justifications
for standards modifications, and provides the effective dates of the
(3) Section 307.3 of this title (relating to Definitions
and Abbreviations) defines terms and abbreviations used in the standards.
(4) Section 307.4 of this title (relating to General
Criteria) lists the general criteria that are applicable to all surface
waters of the state unless specifically excepted in §307.8 of
this title (relating to Application of Standards) or §307.9 of
this title (relating to Determination of Standards Attainment).
(5) Section 307.5 of this title (relating to Antidegradation)
describes the antidegradation policy and implementation procedures.
(6) Section 307.6 of this title (relating to Toxic
Materials) establishes criteria and control procedures for specific
toxic substances and total toxicity.
(7) Section 307.7 of this title (relating to Site-Specific
Uses and Criteria) defines appropriate water uses and supporting criteria
for site-specific standards.
(8) Section 307.8 of this title sets forth conditions
when portions of the standards do not apply - such as in mixing zones
or below critical low-flows.
(9) Section 307.9 of this title describes sampling
and analytical procedures to determine standards attainment.
(10) Section 307.10 of this title (relating to Appendices
A - G) lists site-specific standards and supporting information for
classified segments (Appendices A and C), water bodies that are sole-source
surface drinking water supplies (Appendix B), site-specific uses and
criteria for unclassified water bodies (Appendix D), site-specific
toxic criteria that may be derived for any water in the state (Appendix
E), chlorophyll a criteria for selected
reservoirs (Appendix F), and site-specific recreational uses and criteria
for unclassified water bodies (Appendix G). Specific appendices are
(A) Appendix A - Site-specific Uses and Criteria for
(B) Appendix B - Sole-source Surface Drinking Water
(C) Appendix C - Segment Descriptions;
(D) Appendix D - Site-specific Uses and Criteria for
Unclassified Water Bodies;
(E) Appendix E - Site-specific Toxic Criteria;
(F) Appendix F - Site-specific Nutrient Criteria for
Selected Reservoirs; and
(G) Appendix G - Site-specific Recreational Uses and
Criteria for Unclassified Water Bodies.
(b) Applicability. The Texas Surface Water Quality
Standards apply to surface waters in the state - including wetlands.
(c) Classification of surface waters. The major surface
waters of the state are classified as segments for purposes of water
quality management and designation of site-specific standards. Classified
segments are aggregated by basin, and basins are categorized as follows:
(1) River basin waters. Surface inland waters comprising
the major rivers and their tributaries, including listed impounded
waters and the tidal portion of rivers to the extent that they are
confined in channels.
(2) Coastal basin waters. Surface inland waters, including
listed impounded waters but exclusive of paragraph (1) of this subsection,
discharging, flowing, or otherwise communicating with bays or the
gulf, including the tidal portion of streams to the extent that they
are confined in channels.
(3) Bay waters. All tidal waters, exclusive of those
included in river basin waters, coastal basin waters, and gulf waters.
(4) Gulf waters. Waters that are not included in or
do not form a part of any bay or estuary but that are a part of the
open waters of the Gulf of Mexico to the limit of the state's jurisdiction.
(d) Modification of standards.
(1) The commission reserves the right to amend these
standards following the completion of special studies.
(2) Any errors in water quality standards resulting
from clerical errors or errors in data may be corrected by the commission
through amendment of the affected standards. Water quality standards
not affected by such clerical errors or errors in data remain valid
until changed by the commission.
(3) The narrative provisions, presumed uses, designated
uses, and numerical criteria of the Texas Surface Water Quality Standards
may be amended for a specific water body to account for local conditions.
A site-specific standard is an explicit amendment to this chapter,
and adoption of a site-specific standard requires the procedures for
public notice and hearing established under the Texas Water Code,
§26.024 and §26.025. An amendment that establishes a site-specific
standard requires a use-attainability analysis that demonstrates that
reasonably attainable water-quality related uses are protected. Upon
adoption, site-specific amendments to the standards will be listed
in §307.10 of this title.
(4) Factors that may justify the development of site-specific
standards are described in §307.4 and §§307.6 - 307.8
of this title.
(5) Temporary variance. When scientific information
indicates that a site-specific standards amendment is justified, the
commission may allow a corresponding temporary variance to the water
quality standards in a permit for a discharge of wastewater or stormwater.
(A) A temporary variance is only applicable to an existing
(B) A permittee may apply for a temporary variance
prior to or during the permit application process. The temporary variance
request must be included in a public notice during the permit application
process. An opportunity for public comment is provided, and the request
may be considered in any public hearing on the permit application.
(C) A temporary variance for a Texas Pollutant Discharge
Elimination System permit also requires review and approval by the
United States Environmental Protection Agency (EPA) during the permitting
(D) The permit must contain effluent limitations that
protect existing uses and preclude degradation of existing water quality,
and the term of the permit must not exceed three years. Effluent limitations
that are needed to meet the existing standards are listed in the permit
and are effective immediately as final permit effluent limitations
in the succeeding permit, unless the permittee fulfills the requirements
of the conditions for the variance in the permit.
(E) When the permittee has complied with the terms
of the conditions in the temporary variance, then the succeeding permit
may include a permit schedule to meet standards in accordance with
subsection (f) of this section. The succeeding permit may also extend
the temporary variance in accordance with subsection (f) of this section
in order to allow additional time for a site-specific standard to
be adopted in this chapter. This extension can be approved by the
commission only after a site-specific study that supports a standards
change is completed and the commission agrees the completed study
supports a change in the applicable standard(s).
(F) Site-specific standards that are developed under
a temporary variance must be expeditiously proposed and publicly considered
for adoption at the earliest opportunity.
(e) Standards implementation procedures. Provisions
for implementing the water quality standards are described in a document
entitled Procedures to Implement the Texas
Surface Water Quality Standards (RG-194) as amended and approved
by the Texas Commission on Environmental Quality and EPA.
(f) Permit schedules to meet standards. Upon permit
amendment or permit renewal, the commission may establish interim
effluent limitations to allow a permittee time to modify effluent
quality in order to attain final effluent limitations. The duration
of any interim effluent limitations may not be longer than three years
from the effective date of the permit issuance, except in accordance
with a temporary variance as described in subsection (d)(5) of this
(g) Temporary standards. Where a criterion or designated
use is not attained and cannot be attained for one or more of the
reasons listed in 40 Code of Federal Regulations (CFR) §131.10(g),
or to facilitate restoration or reconfiguration activities that preclude
the attainment of the designated use or criterion, then a temporary
standard for specific water bodies or permittees may be adopted in
§307.10 of this title as an alternative to changing uses.
(1) A temporary standard identifies the interim numerical
criteria or use that applies during the existence of the temporary
standard. When a temporary standard is adopted for permittees or water
bodies, the temporary standard must be expressed as one of the following:
(A) The interim effluent condition that reflects the
greatest pollutant reduction achievable;
(B) Or if no additional feasible pollutant control
technology can be identified, the interim effluent condition that
reflects the greatest pollutant reduction achievable with the pollutant
control technologies installed at the time the temporary standard
is adopted, and implementation of a remediation plan as specified
in the Procedures to Implement the Texas
Surface Water Quality Standards (RG-194); or
(C) The highest attainable interim criterion.
(2) A temporary standard must be adopted in accordance
with the provisions of subsection (d)(3) of this section. Once adopted
by the commission and approved by EPA, a temporary standard is the
applicable standard for the purposes of developing wastewater discharge
permit limits and issuing certifications specified in the federal
Clean Water Act, §401 and Chapter 279 of this title (relating
to Water Quality Certification).
(3) Specific reasons and additional procedures for
justifying a temporary standard are provided in the Procedures to Implement the Texas Surface Water
Quality Standards (RG-194). A temporary standard must identify
the water body or permittee to which the temporary standard applies.
A temporary standard does not exempt any discharge from compliance
with applicable technology-based effluent limits.
(4) A temporary standard must be reevaluated every
five years at a minimum, which may be conducted through the permit
process or a triennial review of the Texas Surface Water Quality Standards.
If the reevaluation is not submitted to EPA within 30 days of completion,
subsequent federal Clean Water Act activities will be evaluated using
the applicable existing underlying water quality standards.
(5) The term of a temporary standard is expressed as
an interval of time from the date of EPA approval or a specific date
cited in the temporary standard. If the continuance of a temporary
standard is sufficiently justified, it can be renewed during revisions
of the Texas Surface Water Quality Standards. When a temporary standard
expires, subsequent discharge permits are issued to meet the applicable
existing water quality standards.
(6) A temporary standard must preclude the degradation
of existing water quality unless degradation is necessary to facilitate
restoration or reconfiguration activities as specified in this section.
(h) Effective date of standards. Except as provided
in 40 CFR §131.21 (EPA review and approval of water quality standards),
this chapter becomes effective 20 days after the date the chapter
is filed in the Office of the Secretary of State. As to actions covered
by 40 CFR §131.21, the rules become effective upon approval by
(i) Effect of conflict or invalidity of rule.
(1) If any provision of this chapter or its application
to any person or circumstances is held invalid, the invalidity does
not affect other provisions or applications of the provisions contained
in this chapter that can be given effect without the invalid provision
or application, and to this end the provisions of this chapter are
(2) To the extent of any irreconcilable conflict between
provisions of this chapter and other rules of the commission, the
provisions of this chapter supersede.
|Source Note: The provisions of this §307.2 adopted to be effective July 10, 1991, 16 TexReg 3400; amended to be effective July 13, 1995, 20 TexReg 4701; amended to be effective August 17, 2000, 25 TexReg 7722; amended to be effective July 22, 2010, 35 TexReg 6294; amended to be effective March 6, 2014, 39 TexReg 1450; amended to be effective March 1, 2018, 43 TexReg 1102; amended to be effective September 29, 2022, 47 TexReg 6216