30 Clear Lake Sites Tested, Cyanobacteria Concern in 6 Lower Arm Areas
Lake County– Summer is a great time for outdoor recreation in Lake County. Many water-based activities, such as swimming, can greatly enhance well-being. Clear Lake is a large and biologically rich natural lake, and offers many opportunities for aquatic recreation. Understanding the dynamic nature of water quality, and what signs to look for when recreating, can help ensure residents and visitors safely enjoy our County’s defining feature.
Water monitoring is regularly done by the Big Valley Band of Pomo Indians and Elem Indian Colony. This is a valuable service, and helps facilitate safe lake use.
The most recent results reflect testing largely conducted July 22, and six areas of Clear Lake demonstrated concerning levels of blue-green algae, also known as Cyanobacteria.
Testing results from 7/22, 7/26/19 - (“danger” level triggering warnings at 20 micrograms per liter µg/L):
Austin Park Beach/AP01 with a lab result of 48 µg/L-Danger Zone (Red);
Redbud Park/RED01 with preliminary testing for microcystin with Abraxis strips on 7/26/19 due to changing lake conditions indicating a level of over 30 µg/L -Danger Zone (Red)*;
Cache Creek Shady Acres/SHADY01 with preliminary testing using Abraxis strips on 7/26/19 due to changing lake conditions indicating a level of over 30 µg/L - Danger Zone (Red);
Lily Cove/LC01 with preliminary testing using Abraxis strips on 7/26/19 due to changing lake conditions indicating a level of over 30 µg/L - Danger Zone (Red)**;
Jago Bay/JB with a result of 4.7 µg/L -Caution Zone (Yellow);
Buckingham Park/BP with a lab result of 2.4 µg/L -Caution Zone (Yellow);
* Lab results from 7/22/19 testing had shown a result of 1.0 µg/L (in the Caution Zone); however, lake conditions changed quickly.
** This site was requested to be tested by a community member due to changing lake conditions, and is not yet a regular sampling site.
CURRENT RESULTS - 2019 SAMPLING RESULTS/LOCATIONS (See Map Below)
GREEN MARKERS - BELOW CALIFORNIA TRIGGER LEVELS
BLUE MARKERS - REGULAR SITES NOT SAMPLED DURING THIS LAST SAMPLING EVENT
YELLOW MARKERS - CAUTION TRIGGER LEVEL
ORANGE MARKERS - WARNING TRIGGER LEVEL
RED MARKERS - DANGER TRIGGER LEVEL
Public Health urges boaters and recreational users to avoid direct contact with or use of waters containing cyanobacteria in Lake County. The recommendation is based on the potential health risks from cyanobacteria, which is currently blooming at varying levels in the Lower Arm of Clear Lake.
Cyanobacteria can pose health risks, particularly to children and pets. We urge people to choose safe activities when visiting natural bodies of water, particularly where blooms are visible. It is strongly recommended that people and their pets avoid contact with water and avoid swallowing lake water in an algae bloom area.
For current cyanotoxin lab results, please visit the Big Valley Band of Pomo Indians cyanotoxin monitoring website:
For more information and resources, visit the County’s cyanobacteria pages: