Upper Blue Lake: toxic algae advisories
Upper Blue Lake, Lake County. See all Lake County waters.
What the state's records say
Caution advisory, last posted Dec 18, 2019. 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 Upper Blue Lake
The state has an advisory on file for Upper Blue Lake (Caution advisory), last posted Dec 18, 2019, 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.
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 |
|---|---|
| Southern end | The state's latest record, from Oct 17, 2024, recommends no advisory. |
| Blue Lakes (Upper Lake) | The state's latest record, from May 29, 2020, recommends no advisory. |
| Upper Blue Lakes | The state's latest record, from Jan 10, 2020, recommends no advisory. |
| (Upper) Blue Lakes (Lake County) | Caution advisory, last posted Dec 18, 2019. No all-clear recorded. |
| Upper Blue Lakes (UBL) | The state's latest record, from Oct 19, 2018, recommends no advisory. |
Advisory history
Every advisory record the state has published for Upper Blue 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 |
|---|---|---|---|
| Oct 17, 2024 | Southern end | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 27, 2024 | Southern end | None | Updates from routine monitoring program-organization |
| Jun 20, 2024 | Southern end | None | Updates from routine monitoring program-organization |
| May 29, 2020 | Blue Lakes (Upper Lake) | None | De-posting advisory. |
| Jan 10, 2020 | Upper Blue Lakes | None | |
| Dec 18, 2019 | (Upper) Blue Lakes (Lake County) | Caution | |
| Oct 19, 2018 | Upper Blue Lakes (UBL) | 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.