Lake Britton: toxic algae advisories
Lake Britton, Shasta County. See all Shasta County waters.
What the state's records say
Caution advisory, last posted Aug 21, 2026. No all-clear recorded.
10 reported spots here have an advisory with no all-clear recorded.
Reporting is voluntary, so the state may not have recorded an end even if conditions changed. Check posted signs and the official map.
What this level asks: Algae that can make toxins may be present. Keep people, children and pets away from algae and scum, and do not let pets drink the water.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Lake Britton
The state has an advisory on file for Lake Britton (Caution advisory), last posted Aug 21, 2026, and no all-clear recorded. Keep your dog out of the water and away from scum on the shore until the state records an end.
Satellite estimate (not an advisory)
Week ending Dec 20, 2025: about 320,000 cells/mL of cyanobacteria near the center of Lake Britton.
A satellite estimate from EPA CyAN for a 4.4 km² lake. It does not measure toxins and does not change the advisory status.
| Week ending | Estimate |
|---|---|
| Dec 20, 2025 | about 320,000 cells/mL |
| Dec 13, 2025 | about 430,000 cells/mL |
| Nov 22, 2025 | about 290,000 cells/mL |
| Aug 10, 2024 | about 470,000 cells/mL |
| Jul 27, 2024 | about 1,800,000 cells/mL |
| Apr 6, 2024 | about 14,000 cells/mL |
| Mar 16, 2024 | about 150,000 cells/mL |
| Dec 16, 2023 | about 540,000 cells/mL |
This is a satellite estimate from the U.S. EPA's Cyanobacteria Assessment Network, not an advisory. It estimates how much cyanobacteria is in the water near the lake's center, not whether toxins are present: a high number does not mean toxins, and a low one does not mean there are none. It covers lakes of about 1 square kilometer and larger, so small ponds, dog parks and most rivers are not covered, and clouds can hide a lake for weeks. It never changes the advisory status above.
Satellite estimates: U.S. EPA Cyanobacteria Assessment Network (CyAN), from Copernicus Sentinel-3 data. Provisional, research-level estimates; EPA does not endorse this site. Checked Oct 22, 2026.
Reported spots
The state records each report at a spot, such as a beach or a boat ramp. Each spot's latest deciding record:
| Spot | Status |
|---|---|
| Lake Britton Picnic Area | Caution advisory, last posted Aug 21, 2026. No all-clear recorded. |
| Jamo Point Boat Launch | Caution advisory, last posted Jul 13, 2026. No all-clear recorded. |
| Lake Britton | General awareness, last posted Aug 16, 2024. No all-clear recorded. |
| State Park Marina | Reports on file, with no advisory level the state has classified. |
| State Park Beach | Caution advisory, last posted Sep 1, 2023. No all-clear recorded. |
| Jamo Boat Launch | Caution advisory, last posted Sep 1, 2023. No all-clear recorded. |
| North Ferry Crossing | Caution advisory, last posted Sep 1, 2023. No all-clear recorded. |
| Lake Britton northshore | The state recorded an end date of Sep 22, 2022. |
| Lake Britton, Jamo Point Boat Launch | Caution advisory, last posted Sep 2, 2020. No all-clear recorded. |
| Lake Britton, Burney Creek Marina dock | Caution advisory, last posted Sep 2, 2020. No all-clear recorded. |
| Lake Britton | Caution advisory, last posted Sep 2, 2020. No all-clear recorded. |
| Lake Britton at State Park Boat Dock | The state's latest record, from Nov 6, 2019, recommends no advisory. |
| Lake Britton | Caution advisory, last posted Jul 14, 2017. No all-clear recorded. |
| Spot not described | The state's latest record, from Sep 9, 2016, recommends no advisory. |
Advisory history
Every advisory record the state has published for Lake Britton, newest first. "None" is the state's record that no advisory was recommended on that date. "NA" records do not change a status.
| Date | Spot | State's level | Notes |
|---|---|---|---|
| Aug 21, 2026 | Lake Britton Picnic Area | Caution | Lake-wide advisory; visual monitoring based advisory |
| Jul 13, 2026 | Jamo Point Boat Launch | Caution | Lake-wide advisory; visual monitoring based advisory |
| Jul 13, 2026 | Jamo Point Boat Launch | Caution | visual monitoring based advisory |
| Jul 8, 2026 | Jamo Point Boat Launch | Caution | Suspected bloom, investigation ongoing |
| Aug 16, 2024 | Lake Britton | General awareness | Under investigation |
| Sep 1, 2023 | State Park Marina | Blank in the state's file | Advisory based on visual and toxins |
| Sep 1, 2023 | State Park Beach | Caution | Advisory based on visual and toxins |
| Sep 1, 2023 | State Park Beach | Caution | Advisory based on visual and toxins |
| Sep 1, 2023 | Jamo Boat Launch | Caution | Advisory based on visual and toxins |
| Sep 1, 2023 | North Ferry Crossing | Caution | Advisory based on visual and toxins |
| Aug 23, 2022 | Lake Britton northshore | General awareness | End date recorded: Sep 22, 2022. Rec general awareness |
| Aug 23, 2022 | Lake Britton northshore | Caution | Floating/planktonic bloom observed; Suspected bloom, investigation ongoing |
| Aug 22, 2022 | Lake Britton northshore | Caution | Floating/planktonic bloom observed; Suspected bloom, investigation ongoing |
| Sep 2, 2020 | Lake Britton, Jamo Point Boat Launch | Caution | Lake-wide advisory |
| Sep 2, 2020 | Lake Britton, Burney Creek Marina dock | Caution | Lake-wide advisory |
| Sep 2, 2020 | Lake Britton | Caution | Lake-wide advisory |
| Nov 6, 2019 | Lake Britton at State Park Boat Dock | None | |
| Jul 14, 2017 | Lake Britton | Caution | |
| Sep 9, 2016 | Spot not described | None |
Source
Advisory data: California State Water Resources Control Board, Freshwater Harmful Algal Bloom Program, via data.ca.gov (public domain). Advisories are recommendations; reporting is voluntary and incomplete. The state's data. An advisory ends only when the state records a later "None" (no advisory recommended) at the same spot, or an end date. A blank end date is unknown.