How Polluted Are LA’s Beaches? The 2023 Heal The Bay Report Card Is Here

Jacob Margolis covers science, with a focus on environmental stories and disasters, as well as investigations and accountability.

Published Jun 14, 2023 12:11 PM

A person carries an umbrella on the pier with a crowded beach in the background.

Just in time for summer fun, the nonprofit Heal the Bay has just released their 33rd annual beach report card to remind us of how polluted (or not) the water we’re all swimming in actually is.

Two of L.A.’s beaches are on the top 10 most disgusting list.

The fecal focused science behind the report card

The report ranks beaches from cleanest to dirtiest based on water quality tests that measure how much fecal indicator bacteria — bacteria found in the digestive tracts of animals and humans — is present in the water. The measurements were taken over the past year during both the wet and dry seasons.

The thinking is that if this limited subset of bacteria, including E. coli, are present in the water, so are dangerous pathogens that can make people quite sick, like vibrio cholerae (which can cause cholera, but is a bit more difficult to test for on its own).

All of the nasty bacteria and viruses, and a whole lot of pollution like petrochemicals, get funneled from our neighborhoods out to the ocean through storm drains when it rains. Pollution levels can stay high for a while, which is why it’s recommended you avoid swimming in the ocean when storms roll through.

How gross are L.A. County beaches?

“Generally the water in L.A. County is pretty clean,” said Alison Wu, water quality data specialist at Heal the Bay, though she’s talking about conditions during the dry periods. Assume water quality is often dismal when it’s wet out.

Two L.A. beaches made the top 10 dirtiest list:

Santa Monica Beach at the pier was on the list, then taken off after they installed a stormwater capture system there, and now it’s reclaimed its spot. The water quality seems to have degraded as a result of the removal of bird netting beneath the pier. A welcome site for birds that want to just sit around and poop in the water, raising fecal bacteria levels. The trash that gets dumped there also doesn’t help.

Mother’s Beach in Marina Del Rey has long been present on the dirtiest beaches list. Given that it’s a beach enclosed in a harbor, water circulation there isn’t great. Most of the poop water is a result of birds, though sewage spills, like the 64,000-gallon one last January, certainly don’t help.

A total of 330,396 gallons of sewage spilled over the course of the year across L.A. County.

What about other counties?

Again, no one did great when it was wet. But when it was dry:

Santa Barbara: 100% of their beaches received an A from Heal the Bay.
Ventura: Received As and Bs during summer, but out of every county in California, had the greatest amount of sewage spilled into their waterways, with 11 million gallons total.
Orange County: Received mostly high grades, though Poche Creek Outlet was on the dirtiest beaches list, as storm drain runoff dumped directly into the water there.

“Ninety-five percent of California’s beaches received excellent grades of A or B last summer,” said Wu. “The water quality here, according to our analysis, is not that bad.”

What about our rivers?

Also accompanying the Beach Report Card is a River Report Card.

Generally, a good indicator of whether river water is clean-ish, is if it’s flowing through non-urban areas.

Places like the Las Virgenes Creek in Malibu State Park (where you can find people often swimming) — and really a whole bunch of spots throughout the lower L.A. River watershed — were often found to be disgustingly polluted.

Places in the San Gabriel River and Upper L.A. River watersheds, including Eaton Canyon, have the lowest health risks associated with them.

So, are our beaches safe?

Generally, yes. Just avoid swimming right after it rains.