What are the Long-Term Bacteria Trends at My Beach, Lake, or Stream?

Understanding trends allows decision makers to determine whether pollution sources are increasing in magnitude and/or frequency and the effectiveness of control measures.

View Trends in Bacterial Indicator Levels

The interactive map below provides sampling results for coastal beach monitoring locations over time. A few county health agencies provide creek and lake information along with ocean beach information. Otherwise, lake and stream information is currently unavailable electronically.

• To find bacterial sample results for a particular site, first select the county, then click on a site location. The results will appear to the right of the map. Results may take time to appear.
• Place your mouse cursor over a point on the chart to see the date and sample result for a particular sample event.

Horizontal lines on the charts represent bacterial water quality objectives specified in the 2005 California Ocean Plan.

• Red is the Single Sample Maximum objective. Sample points above this line represent violations of the objective.
• Blue is the 30-day Geometric Mean objective - the geometric mean of the five most recent samples from each site. Note: Individual sample results above this line do not necessarily represent violations.

National Beach Closures and Postings Trends

Beach water quality information for coastal and Great Lakes beaches. This information may be up to a year out of date.

• U.S. Environmental Protection Agency's Beaches Environmental Assessment and Coastal Health (BEACH) Program