U.S. Water Quality Assessments from EPA ATTAINS

State water quality assessment decisions reported to the U.S. EPA under Clean Water Act Sections 303(d) and 305(b). The dataset provides summary information for each Assessment Unit, as part of the ATTAINS system for tracking water quality and TMDLs. It is maintained by the U.S. Environmental Protection Agency and was last updated in February 2025.

Use Cases

• Analyze Assessment Unit statuses to identify water bodies listed under Section 303(d) for impaired waters.
• Map water quality assessment decisions across U.S. states to evaluate regional compliance with Clean Water Act goals.
• Track the implementation of Total Maximum Daily Loads (TMDLs) by linking summary data to detailed ATTAINS web services.

Strengths

• Data is sourced from the authoritative U.S. Environmental Protection Agency, ensuring regulatory accuracy.
• Covers multiple water types including Surface Water, Ground Water, and Estuaries across the United States.
• Updated regularly, with a last recorded update in February 2025.

Limitations

• Specific data volume, row count, and column schema are not provided, limiting initial analytical planning.
• Data is provided as summary information, requiring access to separate ATTAINS web services for detailed records.
• The ESRI REST format may require specialized GIS software or libraries for full access and analysis.

Provenance

Source

U.S. Environmental Protection Agency (EPA)

Collection Method

State-reported assessments compiled under the Integrated Report (IR) and Clean Water Act.

Freshness

Updated 2025-02-25.

Geography

United States