Water Quality Monitoring Data

Stormwater Monitoring and Assessment Reports

Santa Ana Region of Orange County (north and central watersheds)

Data from water quality and other environmental monitoring efforts in the north and central watersheds of Orange County (Santa Ana Region) is summarized and analyzed on an annual basis in Section 11 of the Orange County Stormwater Program Unified Program Effectiveness Assessment (Unified PEA). The Unified PEA is finalized by November 15th of each year and covers a reporting period of July 1st through June 30th. The 2017-18 Unified PEA (as well as the Unified PEA from prior reporting periods) is available at the following link: 
(Please note that all water quality monitoring data is reported in Section 11 of the document).

San Diego Region of Orange County (south orange County watersheds)

Until a Water Quality Improvement Plan (WQIP) is approved by the San Diego Regional Water Board, the municipal separate storm sewer system (MS4) permit for the watershed management area of south Orange County requires submittal of a transitional monitoring and assessment report (TMAR) by January 31st of each year, covering a monitoring reporting period of October 1 through September 30. The TMARs for the last two reporting periods are available at the links below: 

State of the Environment Reports

2013 Santa Ana Region & 2014 San Diego Region State of the Environment Reports are also available. These reports represent a commitment to periodically present a comprehensive picture of the quality of Orange County’s creeks, rivers, bays and coastal waters and the actions being taken by the Orange County Stormwater Program (the Program) to protect and restore them.

2013 Santa Ana Region State of the Environment            2014 San Diego Region State of the Environment

Monitoring Data Portal

Use the interactive map below to view OC Watersheds monitoring programs, sampling locations, water quality data, and hydrologic monitoring locations.Layer visibility can be adjusted by expanding the layer control in the upper left corner of the map.
(For best performance- use Google Chrome or Mozilla Firefox browser to view map) 

Direct access to OC Watersheds monitoring program data (without using the map)

Click on the monitoring program to download individual data sheets.

Santa Ana Region  San Diego Region
Bioassessment Aliso Creek Bacteria TMDL
Coyote Creek Metals TMDL Ambient Coastal ReceivingWater
Dry Weather Bioassessment
Estuary/Wetlands Coastal Storm Drain Outfall
Mass Emissions Mass Emissions
Newport Bay Nutrient TMDL - Algae Non-Stormwater Action Level
Newport Bay Nutrient TMDL - Watershed San Juan Creek Bacteria TMDL
Nitrogen and Selenium Management Program Stormwater Action Level
Pathogens and Bacteria
For questions on water quality monitoring, please contact:

Data Requests

All data requests should be submitted through MyOCeServices - please select the "Information Only" service request category.