California Surface Water Fecal Bacteria Monitoring Results

State of California data contains fecal indicator bacteria monitoring results for surface waters, including E. coli, enterococci, fecal coliforms, and total coliforms. The dataset provides cleaned and standardized results with calculated 6-week and 30-day geometric means for evaluating long-term water quality trends. It serves as the primary source for the public Safe to Swim Map.

Use Cases

• Assess microbial water quality and health risks for recreational use by analyzing E. coli and enterococci concentrations.
• Evaluate long-term water quality trends and compliance by calculating and comparing 6-week and 30-day geometric means.
• Identify potential contamination sources by analyzing spatial patterns across monitoring sites for fecal coliforms and total coliforms.

Strengths

• Data is cleaned and standardized for consistency, ensuring usability for analysis.
• Includes calculated 6-week and 30-day geometric means, which are key metrics for regulatory compliance and trend evaluation.
• Serves as the primary data source for a public-facing interactive map (Safe to Swim Map), indicating operational relevance.

Limitations

• Rows and columns are unknown, making it difficult to assess the dataset's scale and feature completeness.
• Some records are excluded during processing, such as duplicates or invalid results, which may introduce selection bias.
• Overlap with other source datasets (CEDEN Water Chemistry) may cause confusion without clear join keys.

Provenance

Source

California Environmental Data Exchange Network (CEDEN), BeachWatch database, Central Valley Water Board.

Collection Method

Collected from surface water monitoring programs across California.

Freshness

Last updated March 2026, indicating recent maintenance.

Geography

Surface waters across California, United States.