The Texas Surface Water Quality Standards, Title 30, Chapter 307 of the
Texas Administrative Code
, are
written by the Texas Commission on Environmental Quality (TCEQ)
with the authority of the Clean Water Act and
the Texas Water Code
(Scroll down to Chapter 26 and select Section 26.023.) The
standards establish explicit water quality goals throughout the
state. The standards are set in an effort to maintain the quality
of water in the state of Texas consistent with public health and
enjoyment, protection of aquatic life, and the operation of
existing industries and economic development of the state.
One of the major sections of the standards is the General
Criteria (307.4).
The general criteria are narrative and define the goals to be
attained by all waters in the state. More specifically, they
address pollutants for which there are no specific numerical
criteria and specify procedures to develop site-specific standards
for small unclassified water bodies. The Antidegradation Policy (307.5)
establishes extra protection for water bodies which are defined in
the standards as being of intermediate, high, or exceptional
quality. Specific numerical criteria (307.6) for
39 toxic pollutants (as maximum instream concentrations) protect
aquatic life. Human consumption of fish and drinking water is
protected by numerical criteria for 65 toxic pollutants. Section
307.6 also addresses biomonitoring, which involves exposing
selected aquatic organisms to samples of a discharge effluent. Any
significant toxicity observed during biomonitoring must then be
evaluated and eliminated. Appropriate numerical criteria needed to
support various water-quality related uses are defined in Section
307.7.
Conditions under which portions of the standards do not apply are
noted in Section
307.8.
Sampling and analytical procedures to assess standards attainment
are described in Section
307.9.
Site-specific standards for designated water bodies are
individually listed in Section
307.10
(Appendices A, B, C, D, and E).
The designated water bodies listed in 307.10 are divisions of
major river basins, bays, and estuaries. The waterbodies have been
divided based on regional hydrologic and geologic diversity. The
divisions are defined as segments and referred to as classified or
designated segments. Segments are listed and defined in the Texas
Surface Water Quality Standards and depicted graphically in the Atlas of Texas
Surface Waters, which is a collection of colored maps of the
state showing all the states surface water bodies.
Water quality standards are specific to each segment. They
identify appropriate uses, including aquatic life, contact or
noncontact recreation, and drinking water. They list upper and
lower limits for common indicators (criteria) of water quality,
such as dissolved oxygen, temperature, pH, dissolved minerals, and
bacteria. Other standards, such as toxic criteria to protect
aquatic life and human health are applied statewide. Statewide
standards may be revised on a site-specific basis when sufficient
information is available.
For a brief explanation on Texas Surface Water Quality, see
Texas Surface Water Quality: What is it, and How is it
Measured? (PDF). (Help with PDF Files.)
How the Water Quality Standards are applied to permits is
discussed in the Implementation Procedures.
