Lake Elsinore isn’t safe to swim in. Here's what to know about the toxic algal bloom

People and pets are being warned to avoid all water contact at Lake Elsinore after a harmful algal bloom that could pose a serious health threat was detected in five different areas.

The Riverside County lake has shown extremely elevated levels of toxins, triggering a “danger” advisory, the highest warning available.

Harmful algal blooms are associated with several health risks , including rashes, headaches, and even abnormal breathing if swallowed while swimming.

Marisa Van Dyke, a senior environmental scientist with the State Water Resources Control Board, told LAist that dogs and children are most sensitive to this issue, so it’s safest to stay on dry land until further notice.

“We really recommend if you're going out with your family or with your pets, to take a extra look and see if there's anything unusual going on,” she said.

What you should know

A “danger” advisory is issued when testing shows 20 micrograms per liter of microcystins, but the latest results from Lake Elsinore show levels far beyond that — 36,750 micrograms per liter.

“That's about 1,800 times greater than the advisory levels threshold, so this is very alarming results to get,” Van Dyke said.

Officials say you should stay out of the water entirely, including on boats, jet skis, and paddle boards.

You shouldn’t eat any fish or shellfish from the lake, and if you’ll be camping or picnicking in the area, avoid using the water for drinking or cooking.

“For harmful algal blooms, we know boiling water doesn't help,” Van Dyke said. “And then most filtering systems that you can get for backpacking are not adequate for filtering out this concern.”

You should steer clear from water that has an odd color, suspicious scum, or smells.

People who swallow or come into contact with it may experience congestion, hives, vomiting, earaches, and irritated eyes within two days of exposure. Children are considered more at risk because of their smaller size, higher chance of swallowing while swimming, and tendency to stay in the water longer.

If you do start showing symptoms or feeling sick, get medical treatment immediately and contact the Riverside County Department of Public Health.

“Danger” signs have been posted around Lake Elsinore to warn people, but Van Dyke said you should always scan the water before jumping into your favorite swimming spot.

You can also always check California’s harmful algal bloom map to see if any outbreaks have been reported in the area.

What about furry friends?

Animals can get very sick, or even die, from being exposed to harmful algal blooms.

Dogs, like children, are most susceptible to exposure. The slimy material from the water can get in their mouth while playing fetch or get stuck to their fur, Van Dyke noted.

Bring bottled water for your dogs to drink, and if they do get in with a bloom, don’t let them lick their fur until they’ve been thoroughly cleaned off.

If your pet starts showing symptoms like vomiting, diarrhea, or seizures after coming into contact with water — call your veterinarian right away. You can also share this fact sheet with the vet to help identify the illness.

Why this water

The harmful algal blooms that pop up in lakes and rivers are often caused by cyanobacteria, which are small microbes that live in just about every habitat.

“But there's certain conditions that we experience in California that really drive their growth in some at-risk waterways, and when they grow a lot, and you can see them with the naked eye, then we call these blooms,” Van Dyke said.

Some cyanobacteria can produce harmful toxins, and according to the State Water Resources Board, Lake Elsinore’s shallow waters and warmer temperatures has made it particularly vulnerable to outbreaks, especially during this time of year.

The city of Lake Elsinore regularly tests for harmful algal blooms as part of its “ Lake Watch ” program and shares satellite pictures of the water conditions.

More resources

If the water seems suspicious and you’re not sure if it's a harmful algal bloom, you can submit a report here .

You can also report a bloom by calling the toll-free hotline 1-844-729-6466, emailing cyanoHAB.reports@waterboards.ca.gov , or by contacting your public health department.

“People are really, you know, our best kind of like line of defense and letting us know where to go take a look at, because we have so many lakes and river beaches in the state, it is challenging to be able to monitor them all proactively,” Van Dyke said.

She added that the State Water Resources Control Board is normally able to respond to online reports in one business day to let you know if the water is worth worrying about, especially if you include photos.

You can find more information about harmful algal blooms here .