Its summer and Mission Bay is a hotspot as temperatures rise and thousands come to cool off in these waters, but San Diego Coastkeeper's newest report suggests some areas of the bay may not always be as safe for recreation as they appear.
Coastkeeper has been monitoring water quality in Mission Bay since 2023.
Each month, trained volunteers collect water samples from ten locations across the bay, testing for bacteria, metals and nutrients.
“We’re sampling not only along the shore but also mid-channel sites,” Laura Fuller, Community Science Director with San Diego Coastkeeper says.
Some of the findings were expected.
“After a rain event you're gonna see elevated. Metals, nutrients, and fecal bacteria in the water throughout the whole bay,” Fuller says.
But one trend stood out: “In the warm weather when there's no rain, sometimes we see elevated metals,” Fuller explains.
The report found waterways including Rose Creek and Tecolote Creek exceeded recreational safety standards at least half the time — even when it hadn't rained.
That has researchers like Fuller asking why; “It makes me think maybe there's some discharge happening that shouldn't be happening."
Coastkeeper says the data can help identify whether there is aging wastewater infrastructure or illicit discharges, and guide future solutions.
“Knowledge is power,” Fuller says. “We have this data backed knowledge now and so the question is what are we going to do with that knowledge?.”
Volunteers will continue monitoring the bay throughout the summer, testing the water and reporting when conditions may be unsafe.
Before heading into the water, Coastkeeper recommends checking both the county's water quality reports and their online advisory map.
That way, visitors can make an informed decision before diving in.
