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Texas Water Quality Inventory and 303(d) List - Reporting Categories

A description of categories that describe water quality conditions. The categorization of water bodies assists management activities.

Guidance from the U.S. Environmental Protection Agency for the Texas Water Quality Inventory and 303(d) List requires that all water bodies be placed into one of five categories. Each assessed area, or assessment unit (AU), must be categorized by how it meets its designated uses.

Description of Categories

One of five categories is assigned to each parameter and water body to provide information about water quality status and management activities. When a water body has parameters in multiple subcategories, its overall category is the highest category.

Category 1—Attaining the water quality standard and no use is threatened.

Category 2—Attaining some of the designated uses; no use is threatened; and insufficient (or no data) are available to determine if the remaining uses are attained or threatened.

Category 3—Insufficient data (or no data) to determine if any designated use is attained.

Category 4—The standard is not supported or is threatened for one or more designated uses but does not require the development of a Total Maximum Daily Load (TMDL).

Category 4a—A TMDL has been completed and approved by the EPA.
Category 4b—Other pollution control requirements are reasonably expected to result in the attainment of the water quality standard in the near future.
Category 4c—Nonsupport of the water quality standard is not caused by a pollutant.

Category 5—The water body does not meet applicable water quality standards or is threatened for one or more designated uses by one or more pollutants.

Category 5a—A TMDL is under way or scheduled, or will be scheduled.
Category 5b—A review of the water quality standards will be conducted before a TMDL is scheduled.
Category 5c—Additional information will be collected before a TMDL is scheduled.

For a more detailed explanation of the categories, see 2002 Strategy for a Comprehensive Assessment and Categorization of Waters in Texas (PDF, October 1, 2002). (Help with PDF.)

Category Reports

These files are in Portable Document Format (PDF). (Help with PDF.)

  • Summary of the 2002 Texas Water Quality Inventory (Categories 1-5), Full document (449 pages, ~930KB).