Trinity Lake: toxic algae advisories
Trinity Lake, Trinity County. See all Trinity County waters.
What the state's records say
The state's latest record, from Sep 2, 2026, recommends no advisory.
That reflects what the state knew on that date. It is not a finding that the water is safe now: blooms can return within days, and many are never reported.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Trinity Lake
The state's latest record, from Sep 2, 2026, recommends no advisory. For Trinity Lake, that is not the same as an all-clear for today. Look at the water before your dog goes in: keep it out of green, blue-green or scummy water and away from mats on the shore.
Satellite estimate (not an advisory)
No satellite reading on file for Trinity Lake in recent weeks. Clouds, ice, or a lake shape the satellite's estimate near its center misses can cause this. It is a gap in the data, not a reading.
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 |
|---|---|
| Resort (106TLRSRT) | The state's latest record, from Sep 2, 2026, recommends no advisory. |
| Lakewide | The state's latest record, from Oct 28, 2022, recommends no advisory. |
| Buckeye | The state's latest record, from Jul 6, 2021, recommends no advisory. |
| Bowerman Buck | The state's latest record, from Jul 6, 2021, recommends no advisory. |
| at Estrallita | The state's latest record, from Jul 6, 2021, recommends no advisory. |
Advisory history
Every advisory record the state has published for Trinity Lake, 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 |
|---|---|---|---|
| Sep 2, 2026 | Resort (106TLRSRT) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jun 25, 2026 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers |
| May 14, 2026 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers |
| Nov 6, 2025 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers |
| Aug 20, 2025 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jun 18, 2025 | Resort (106TLRSRT) | None | Updates from routine monitoring program-organization |
| Oct 25, 2024 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers; Updates from routine monitoring program-organization |
| Aug 22, 2024 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jul 1, 2024 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers; Updates from routine monitoring program-organization |
| Oct 30, 2023 | Resort (106TLRSRT) | None | Testing results below posting triggers |
| Aug 28, 2023 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers |
| Jul 5, 2023 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers |
| Jul 5, 2023 | Resort (106TLRSRT) | None | No cyano bloom w/testing; Testing results below posting triggers |
| Oct 28, 2022 | Lakewide | None | End date recorded: Oct 28, 2022. Testing results below posting triggers; Updates from routine monitoring program-organization |
| Oct 28, 2022 | Lakewide | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Sep 14, 2022 | Lakewide | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jun 21, 2022 | Lakewide | None | Updates from routine monitoring program-organization |
| May 31, 2022 | Lakewide | None | Updates from routine monitoring program-organization |
| Jul 6, 2021 | Buckeye | None | Testing results below posting triggers |
| Jul 6, 2021 | Bowerman Buck | None | Testing results below posting triggers |
| Jul 6, 2021 | at Estrallita | None | Testing results below posting triggers |
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.