Lake Watch - Current State of Lake Elsinore

Update as of May 24, 2023

Based on recent lab results from lake water sampling and guidance from the California State Water Board, the City of Lake Elsinore is announcing that current levels of toxins from algae warrant the posting of a “Caution” advisory. Under this advisory, and per the CA State Water Resources Control Board, people may engage in all forms of recreation, including swimming, boating, and fishing.  People are advised to stay away from any remaining visible algae, to not drink lake water, and to continue to keep pets out of the water.  Have fun and be safe on the lake!

The City will continue to test the water on a weekly or bi-weekly basis at this time and will post regular updates on the lake conditions as lab results are received. 

Launch Pointe RV Resort and the boat launch at Launch Pointe will still be open for business advising all visitors of the status of the lake. Lake Use Pass Holders will be notified should the terms of their passes be amended. 

Current Status: 

Screenshot 2023-05-18 104947

For lake testing information and the latest lab results - CLICK HERE


Q:  How often and where are lake samples collected for testing?  

A:  During periods of “Danger” advisory levels, testing occurs on a weekly basis.  When toxins are at lower levels testing occurs on a bi-weekly or monthly basis.

Q:  Who collects the samples and conducts the testing?

A:  The City contracts with WSP Environment & Infrastructure for sampling.  WSP prepares, packages, and overnights the samples to Greenwater Labs in Florida.  Test results are usually received within 3-5 business days of the collection date.  Testing is primarily for microcystin, the most common type of cyanotoxin in Lake Elsinore.  Other toxins might be assessed depending on current lake conditions.

Q:  Are boats allowed on the lake when a “Danger” advisory is in effect?

A:  Lake users are advised to stay out of the water and to not engage in any recreation activities when toxin levels are at a “Danger” advisory level.

Q:  At what advisory level is it safe to swim, jet ski, ski/wakeboard, or engage in other activities that result in contact with the water?

A:  Lake users are advised to not contact the water at the “Danger” or “Warning” advisory levels.  Swimming is allowed at the “Caution” level but water should not be ingested.

Q:  Is it safe to eat fish caught when an advisory is posted?

A:  Fish caught in the lake should not be eaten when a “Danger” advisory is present.  During a “Warning” or “Caution” advisory fish should be cleaned and guts thrown away and fillets should be cleaned with tap water or bottled water before cooking.

Q:  When is it safe for pets to go in the water?

A:  Pets should not go into or drink the water any time an advisory of any level is posted.

Q:  What is the City of Lake Elsinore doing to reduce toxins from algae?

A:  The City, partner agencies, and lake scientists are continually looking at methods and researching treatment options.  In a recent study, four treatments were tested and analyzed in enclosed study areas near the Launch Pointe public beach.  A final report of that study, which included chemical and microbial strategies, will be released by mid-2023.  The City has also applied for a grant and federal funding to conduct a pilot study that utilizes a technology to physically remove algae from the lake with a harvesting system.  Award notices for that funding should be released in July 2023. 

Q: Is the LEAMS system operating and is it helping to reduce toxic algae blooms?

A:  The Lake Elsinore Aeration and Mixing System (LEAMS) is operational.  However, the consensus amongst the scientific community is that the system is nearing the end of its useful life and that the system has a minimal effect on reducing toxic algae blooms.  The City and Elsinore Valley Municipal Water District are continually monitoring the system and are currently exploring options for upgrading, repurposing, or replacing the system.

Q:  Why aren’t alum, copper sulfate, or other algaecide treatments applied to Lake Elsinore?

A:  These treatments have been considered and researched and could possibly be part of the mix of treatments.  However, it is generally agreed upon that there isn’t one treatment that will serve as a “silver bullet” to eliminate toxic algae blooms in Lake Elsinore due to the size and complexities of the lake.  These treatments are considered as short-term solutions and would need to be applied regularly at a high volume and cost due to the size of the lake (3,000 acres).


See latest water monitoring results and advisories available on the State's Harmful Algae Bloom Portal.  Be sure to scroll to Lake Elsinore or Riverside County to view details. 

Lake Elsinore has historically been vulnerable to algae blooms, but only began sampling for or learning about Cyanobacteria concerns in 2016. Sampling is only conducted as needed based on the state of the lake. 

View Trigger Levels determined by the State 

View Caution (Espanol), Warning (Espanol) and Danger (Espanol) Signs 

State Website regarding Harmful Algae Blooms (HAB) - Zoomed in HAB Map of Lake Elsinore

Find out more about Cyanobacteria, i.e. Harmful Algae Blooms

Harmful Algae Bloom Fact Sheet and FAQs

Read an FAQ regarding Posted Signs Related to Harmful Algae Blooms 

Physician Fact Sheet

Dog Owners Fact Sheet 

Lake Elsinore is located at the bottom of the 720 square-mile San Jacinto Watershed. Rainfall throughout this area flows downstream through various tributaries into Canyon Lake before spilling into Lake Elsinore. This “run-off” brings critical water supply for the lakes, but is also susceptible to carrying with it nutrients and sediment that can be detrimental to the lakes’ water quality over time by encouraging algae growth. 

About Lake Elsinore's Health 

Lake Elsinore is Southern California’s Largest Natural, Freshwater Lake. Faced with a historic drought, extremely low water levels, higher temperatures, and an abundance of shad, the City has become increasingly concerned about the health of the lake and the vitality of the fishery.

In 2015, in an effort to be proactive and prepared, the City partnered with the Lake Elsinore & San Jacinto Watersheds Authority (LESJWA) launched Lake Watch 2015 to create awareness and engage the community, local and regional resource agencies and private businesses to take part in our efforts to prepare for and address the vulnerability of Lake Elsinore.

The City started its Lake Watch efforts to get prepared and regularly inform the community about the health and concerns of our most valuable asset - Lake Elsinore. While the City and the Elsinore Valley Municipal Water District each spend more than $750,000 per year to add 5 million gallons of recycled water to the lake each day, it is not enough to offset evaporation. In 2016, lake's water level declined to its lowest levels since early 1993 and was extremely vulnerable to algae blooms and subsequent fish kills. At this time, we suffered our first detected blue-green algae bloom.

In 2017, storms helped to replenish the lake and the water quality greatly improved. However, 2018 was amongst one of our driest years on record and the lake levels have once again declined well below the optimal level of 1240’. Ultimately, the lake needs more rain and the City remains diligent in monitoring the lake's health and working toward long-term options to improve the overall health of Lake Elsinore.

Find out more about the Lake Elsinore & San Jacinto Watersheds Authority (LESJWA)

Learn about the latest projects completed in Lake Elsinore

2022 Aquatic Pesticide Application Plan for Lake Elsinore (Click Here)

In an effort to improve Lake Elsinore's health, the City has proactively sought out innovative solutions to address algae growth on the lake. To ensure the Lake is managed and treated appropriately, the City is working on a study to evaluate best management practices and precautions that will be implemented to protect surface waters within Lake Elsinore.

The public is encouraged to share their thoughts about this plan during the public comment period from August 18, 2022 to September 19, 2022 at 12:00 p.m. Comments received after Noon on the comment due date will not be considered. Comments may be submitted via email: or by mail to:
Attention. Gurgagn Chand
State Water Resources Control Board, Division of Water Quality
1001 St, 15th Floor,
Sacramento, CA 95814

Algae & Algae Blooms 

Algae are large photosynthetic organisms and are normal habitats of large bodies of water like a lake. Algae are very important to both freshwater and marine environments and most species are harmless under normal circumstances. Cyanobacteria are known as “blue-green algae” are actually bacteria and not a form of Algae. Algae and Cyanobacteria have very similar characteristics with the difference that certain Cyanobacteria toxins can be harmful to the environment, animals and human health.

Algae blooms occur when the algae grow at rapid speeds than normal causing dense accumulations in the water. Algae blooms are normal occurrences in bodies of water. They can become harmful when there is excessive growth. As the cyanobacteria die off, harmful toxins can be produced known as cyanotoxins Concerns regarding blue-green algae have been on the rise throughout the Country and California including Pyramid Lake, Discovery Bay, Lake Elsinore, and Silverwood Lake.

Find out more about Cyanobacteria, i.e. Harmful Algae Blooms

Read an FAQ regarding Posted Signs Related to Harmful Algae Blooms 

Fish Kills 

In 2015, a fish survey conducted on behalf of LESJWA found that Lake Elsinore’s fishery is imbalanced due to an overpopulation of Threadfin Shad. Shad are small, highly sensitive fish that hinder the water quality by eating microscopic zooplankton, which consume algae. With Shad feeding on the zooplankton in the lake, there will likely be an algae bloom thus reducing dissolved oxygen. Such conditions, ultimately lead to the demise of this delicate fish. It is nature’s way to rebalance the fish population and improve the overall health and quality of the lake.

Since 2000, the City and LEJSWA in coordination with its partner agencies have greatly improved water quality and wildlife habitats in Lake Elsinore, as well as in the surrounding watershed. Successful projects to date include the following:

  • Lake Elsinore Wetlands Enhancement Project
  • Lake Elsinore Carp Removal
  • Island Wells Pump Station Improvements
  • Striped Bass Stocking
  • Lake Elsinore Destratification & Mixing System
  • Recycled Water Nutrient Removal & Conveyance Pipeline
  • Lake Habitat Improvements
  • Lake Elsinore Fisheries Management Report 

Despite these efforts, Lake Elsinore is a natural lake. A fish kill is one of Nature’s ways of rebalancing the food chain. While there is no indication currently that an event is imminent, the probability is always high during the hot summer months. 

In 2015 and 2018, Lake Elsinore did suffer a moderate fish kill. The City remains prepared and regularly monitors the dissolved oxygen in the lake for signs of concern.

Read the latest Lake Elsinore Fisheries Management Report, published in September 2020

Read press release announcing completed Lake Elsinore Fisheries Management Report 

Lake Watch

Lake Elsinore is an extremely complex, unique water body. It is a show lake that struggles due to increasing temperatures, recent algae blooms, and declining dissolved oxygen levels during the hotter months. Unfortunately, there is little the City or LESJWA can do to improve its current condition without a stable and reliable water level of above 1240'. 

Lake Watch is focused on ensuring the City, regional partners and the community is ready and prepared for any potential concerns related to the vulnerability of Lake Elsinore including declining lake levels, algae blooms and the potential of a fish kill.  

As part of Lake Watch, the City of Lake Elsinore and LESJWA asks the community and visitors to monitor the lake and notify the City should you notice anything abnormal including algae blooms or dead fish floating in the lake or washed up on shore.

To report, please call 951-674-3124 ext. 204, email or message the City at