The 2024 Surfrider Foundation's Clean Water Report revealed that at the mouth of San Luis Creek in Avila Beach, is a top-10 bacteria hotspot.
Since 2012, Niel Dilworth and the SLO County Chapter of the Surfrider Foundation have been collecting weekly water samples at Avila Beach and the mouth of San Luis Creek. For the past three years, the water quality report conducted by the organization has found high bacteria rates between 34-38%.
“It means the sample that was tested had bacteria levels that were high enough that the state advises that you avoid contact with the water," Dilworth said.
The testing is done at the Central Coast Aquarium, which sits right across the street from the mouth of San Luis Creek, a hotbed for enterococci bacteria or fecal matter. The executive director of the aquarium, Christy Kasarjian, said the water quality has a ripple effect.
“The water quality affects what we can provide to the different species that we have on display here for our visitors,” Kasarjian said.
Senior Aquarist Tatum Schneider used to collect the same type of water samples while in school in Los Osos and now that she works in Avila Beach, she says they are two vastly different sample areas in terms of bacteria.
“It's a lot higher," Schneider said of the bacteria count in Avila Beach compared to Los Osos. "There's a lot more of those bright blue wells that you see in the testing.”
Environmental Health Services of San Luis Obispo County does weekly testing as well on Mondays from April 1 through October 30, while Surfrider does theirs year-round on Thursdays. Director Pete Hague said that between June 12, 2024 and May 28, 2025, there were seven health advisories issued at the mouth of San Luis Creek, with only one of them lasting more than a day. Advisories indicate that bacteria levels exceeded the state requirements for safe water conditions.
So if there are continuously high bacteria levels, what’s being done? In August 2024, Dilworth and the local Surfrider chapter began using DNA testing to determine the sources of pollution coming from the creek.
“If there are sources into the bacteria in the creek that we can do something about and then we can find out if we can get that done,” Dilworth explained.
That yearlong data collection will then be combined and presented to the newly formed Avila Beach Bacteria Workgroup, which includes staff from SLO County Public Works, Environmental Health Departments, and the California Water Board.
“All of those people that are showing up there in some way or another are looking at and are concerned about the water quality in the creek," Dilworth added. "We are moving in a direction that hadn't been happening a year before to have all these agencies at least talking about this.”
The final goal is to improve the water quality to a point where Surfrider doesn't have to collect samples anymore.
“It's cleaning up the water so people can use it for recreational purposes without having to worry about the water quality," Dilworth concluded.
The next order of business for the local Surfrider chapter is to put together a year's worth of data on the DNA testing from the Pismo and Avila sites to help paint a better picture of the different sources contributing to the pollution. That data will be brought to the Avila Beach Bacteria Workgroup in July.
