Filling in testing gaps and tracking pollution sources on California’s Central Coast with the Blue Water Task Force
San Luis Obispo (SLO) County offers sweeping coastal vistas, beautiful sandy beaches, great surf breaks, and vibrant tidepools and marine life to explore for all who enjoy visiting the area or are fortunate enough to call it home. Located on California’s Central Coast, SLO County is not as populated or developed as the larger urban centers in the Bay Area or near Los Angeles. Coastal recreation and tourism, agriculture, and vineyards and wineries make up a significant part of the local economy. To protect their treasured coastline, the SLO County Chapter of the Surfrider Foundation has been working hard for over 30 years to combat the mounting pressures of over-development, climate change, and pollution from oil spills, agriculture, stormwater, and sewage infrastructure on their beaches and local water quality.
In 2012, the SLO Chapter first launched its Blue Water Task Force (BWTF) program with two volunteers collecting weekly water samples at Avila Beach and at the mouth of the San Luis Creek. The chapter partnered with the Central Coast Aquarium, conveniently located in Avila Beach, to host their lab. They established a sampling schedule to complement the beach monitoring program conducted by the SLO County Environmental Health Department. The County tests on Mondays, while the chapter collects samples later in the week, so there are fresh test results on Fridays to inform safe recreation over the weekend. From this humble beginning, the SLO BWTF has grown into a large volunteer-run program that monitors 21 beaches and creek sampling sites from Pismo Beach up to San Simeon in the northern part of the County. In 2014, the SLO Chapter helped the Cal Poly Surfrider Student Club establish a second BWTF lab on their campus. The students collect samples at beaches and surf breaks in and around Morro Bay and process them in the lab on campus. A third lab was established in North SLO County in 2020. It was originally hosted at the Monterey Bay National Marine Sanctuary’s Coastal Discovery Center but was later relocated to a local school due to renovations. The team is looking forward to engaging students in the lab starting next school year.
Avila Beach, California
After posting on the BWTF website, the chapter shares its test results through water quality email reports and on its social media platforms. Their data is even linked on the SurfSafeSlo website, hosted by the County Health Department, which the chapter partnered with to post four advisory signs at the mouth of San Luis Creek, featuring a QR code that directs people to the latest water quality data. The year-round water quality information that the SLO BWTF is generating is critical to informing safe recreation at the beach and in coastal waters in the community, especially this past winter, as the County’s beach program was forced to scale back its testing due to budget limitations.
Tracking Pollution Sources
One of the chapter’s first testing sites that showed signs of pollution with frequent high bacteria levels was at the mouth of San Luis Creek at Avila Beach. This is concerning because families often set up their beach blankets at the mouth of this creek to let their children play in its relatively calm, shallow water. Curious about how far up the creek this contamination might extend and whether they could pinpoint sources of pollution, the chapter added five additional sampling sites in the creek over the years. However, the test results at each site continued to show signs of contamination. In 2022, the chapter released a 10-year water quality report that summarized its program findings and discussed the documented bacteria problems in San Luis Creek. This report was shared with staff at the County Health Department and State Water Board in hopes of convincing these agencies to further assess and identify the contributing sources of pollution so they can be resolved. Potential sources of pollution in the watershed include leaking septic systems, sewer line failures, animal agriculture, pets, birds, and other wildlife.
The following year, the chapter’s sampling site at Avila Beach, located at the mouth of San Luis Creek, landed on the national list of Beach Bacteria Hot Spots in the Surfrider Foundation’s annual Clean Water Report. This list highlights 10 popular recreational beaches where Surfrider’s BWTF has consistently detected bacteria levels exceeding state health safety standards. The mouth of San Luis Creek has remained on Surfrider’s national list for the past three years, with high bacteria rates of 34% – 38%. That means more than 1 in every 3 samples collected fail to meet safe swimming standards at this popular spot for children to play, paddle, and splash around in the water. With this new notoriety, the chapter has received a lot of media attention to help raise public awareness of the pollution problems in San Luis Creek and their efforts to find the sources of pollution. Check out the news story below that ran multiple times on local TV stations in June 2023.
Pollution problems in San Luis Creek covered by KEYT/KCOY featuring Niel Dilworth with the SLO BWTF program, June 2023.
With community awareness and concern growing, the chapter decided to conduct a pollution source study to provide more information on the contributing sources of pollution at Avila Beach and in San Luis Creek, as well as at two sites in Pismo Beach that frequently show high bacteria levels. In August 2024, they started collecting monthly fecal indicator bacteria and eDNA samples to determine which species are contributing to the bacterial contamination. Regular water quality tests that measure enterococcus and other fecal indicator bacteria only tell us that there is waste from a warm-blooded animal (or a human) in the water, but they don’t differentiate between species. More specific information is needed to identify the exact sources of pollution so they can be found and fixed. All samples are analyzed for enterococcus bacteria in the chapter’s lab, while eDNA samples are shipped to Jonah Ventures, a professional laboratory, to determine the presence of E. coli and human, cow, dog, poultry, sheep, and swine eDNA. The chapter aims to complete this study in July 2025 after a full 12 months of testing, but preliminary results indicate that eDNA from humans was associated with elevated levels of bacteria in San Luis Creek and Pismo Creek/Estuary, and to a lesser extent at Avila Beach. When the study is complete, the chapter intends to discuss its findings and determine necessary actions with a newly formed Avila Beach Bacteria Workgroup, which includes staff from the SLO County Public Works and Environmental Health Departments, as well as the CA Water Board. The chapter’s ultimate goal is to find the sources of pollution in the San Luis Creek and Pismo Creek Watersheds, so local authorities can fix these problems and restore clean water for everyone to enjoy at the beach.
Top Left: Children play in the San Luis Creek despite warning sign. Bottom Left: A water sample is collected from the surf near Morro Rock. Right: UV light is used to read test results in the lab.
If you're planning a visit to the area, connect with the San Luis Obispo Chapter for information on local events and current water quality conditions. And don’t forget to check out the latest Clean Water Report!