Pathogens in San Diego's Water

Winter in San Diego is a fairly predictable time for locals –we get a few rainstorms followed with warnings to stay out of the water. We also get sewage spills that release fecal-associated pathogens into San Diego’s waters.

Why does this matter? Pathogens make us sick. They are disease-causing microorganisms and include viruses, bacteria and protozoa. These microbes infect us through our skin and mucous membranes and when we drink contaminated water.  The resulting illnesses range from mild to severe symptoms (skin rashes, sore throats, ear, eye and respiratory infections, stomach aches, minor or serious cases of nausea and dysentery and fever). The ultimate origin of these pathogens is the feces of any warm-blooded animal, including humans, pets, livestock and wild animals.  

It is difficult to measure every type of pathogen in San Diego’s waters. That is why when water quality volunteers monitor our local waters, they measure indicator bacteria – microbes that are associated with pathogens and are easily measured. These fecal indicator bacteria are a substitute for pathogens and help us understand the risk posed to recreational users. The diverse range of pathogen types and diverse sources (some are human caused, some are natural) makes this a challenging type of pollution to monitor, manage and eliminate.  

At Coastkeeper, we recognize the health, environmental and economic impact pathogen pollution in our local waters.  There are too many water bodies in the San Diego region that are polluted with pathogens.  That is why we work with the Regional Water Quality Control Board and local municipalities to develop a Total Maximum Daily Load (TMDL) plan to reduce the amount of pathogen pollution reaching our water bodies. This plan will address pathogen pollution at 20 beaches and creeks in five watersheds in Orange County and eight watersheds in San Diego County. The combined watersheds affected by this TMDL cover roughly 1,740 square miles.  The TMDL tries to separate and identify the pathogens that stem from human-related activity from natural ones and sets aggressive interim targets for reduction over ten to twenty years. This plan was finalized in February 2010.

In addition to working with regulatory agencies and local government, Coastkeeper also actively monitors our creeks, rivers and lagoons for pathogens.  We do this on a monthly basis to better understand how much pathogen pollution exists in our local waters. We are also developing a wet weather monitoring program in Chollas Creek to capture more information during rainstorms – a critical period of high inputs into water bodies.