San Diego Coastkeeper Releases 2025 Mission Bay Water Quality Report

SAN DIEGO, Calif. – San Diego Coastkeeper published its 2025 Mission Bay Water Quality Monitoring Report, documenting a second year of monthly water quality data at ten locations throughout the Bay. The report finds that storm events continue to drive sharp spikes in bacteria, metals, and nutrients across all sites, while Tecolote Creek and Rose Creek water quality is very poor, even during dry weather, pointing to chronic, year-round pollution sources that require urgent attention.

Now in its second year, Coastkeeper’s Mission Bay Watershed Watch program has built a network of more than 260 trained community volunteers who collect water samples monthly alongside Coastkeeper staff. Samples are analyzed at a private certified laboratory and the data is shared with the public, primarily through an interactive data map at www.sdcoastkeeper.org/mb-wqm. Coastkeeper also submits all the data to the California State Water Resources Control Board’s California Environmental Data Exchange Network (CEDEN) to inform future regulatory action.

Key findings

• Bacteria levels spiked across all ten sites following rain events. Tecolote Creek and Rose Creek had very high bacteria counts throughout the year that exceeded safe recreation standards at least 50% of the time, including in dry weather. This indicates chronic contamination sources such as aging wastewater infrastructure or illicit discharges.
• Phosphorus exceeded water quality objectives 75% of the time at creek sites, with nitrogen concentrations also highest at Tecolote and Rose Creeks compared to open Bay locations.
• Copper concentrations exceeded applicable standards 100% of the time across all sites. Zinc exceeded standards 75% of the time at Rose Creek. At South Shores, barium remained consistently elevated throughout the second half of the year, potentially linked to large scale fireworks displays at that location.

Together, these findings underscore both the acute impacts of storm events and persistent, chronic water quality challenges concentrated at the Bay’s creek inflows, areas the report identifies as priority targets for investigation and management.

“The findings in our report highlight the urgent need to increase funding for stormwater infrastructure, and to investigate persistent pollution that threatens the health of people recreating in Mission Bay,” said Phillip Musegaas, Executive Director of San Diego Coastkeeper. “The City of San Diego must make it a priority to identify and eliminate the chronic stormwater and sewage pollution sources that foul the Bay, for the benefit of San Diegans and the marine life that call the Bay home.” 

Program achievements

The Mission Bay Water Quality Monitoring program reached several milestones in 2025:

• A cumulative network of more than 260 trained volunteers, up from 180 at the close of 2024
• 28 sampling events completed, including 24 with volunteers and 4 staff-only events for PFAS and stormwater sampling
• 143 stipends distributed to volunteers, supporting equitable access to environmental stewardship
• Ongoing bilingual communications and carpooling coordination to lower participation barriers
• Active participation as a leading member of the ReWild Mission Bay Coalition, supporting plans to restore and expand tidal wetland habitat in the northeast corner of Mission Bay. 

“Now over two years strong, this program emphasizes the importance of centering community participation in local science efforts, cultivating a more environmentally aware and empowered society, while also collecting crucial data needed to drive and advocate for impactful policy changes in the face of a changing climate and rising sea levels,” explained Lesly Gallegos, Volunteer and Outreach Manager at Coastkeeper.

Recommendations and next steps

The report calls for a dedicated funding source to address the City of San Diego’s estimated $5 billion stormwater infrastructure deficit, approval of plans to expand and restore tidal wetland habitat, targeted source investigations in Rose and Tecolote Creek watersheds, and a transition from fireworks to drone light shows at SeaWorld. Coastkeeper is committed to continuing monitoring through at least 2026 and is seeking funding to extend the program through 2028 to build a five-year dataset supporting long-term policy advocacy.

The full 2025 Mission Bay Water Quality Monitoring Report is available here.

About Coastkeeper

Founded in 1995, San Diego Coastkeeper safeguards our region’s inland and coastal waters through a strategic blend of community science, education, grassroots outreach, policy advocacy, and legal enforcement of environmental laws. This approach allows us to effectively tackle the most pressing water issues facing our region. For more information, visit sdcoastkeeper.org.