Lake Gregory: toxic algae advisories
Lake Gregory, San Bernardino County. See all San Bernardino County waters.
What the state's records say
Caution advisory, last posted Aug 29, 2024. No all-clear recorded.
4 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 Gregory
The state has an advisory on file for Lake Gregory (Caution advisory), last posted Aug 29, 2024, 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 |
|---|---|
| Dam | The state's latest record, from Sep 3, 2026, recommends no advisory. |
| Whole Lake | The state's latest record, from Aug 5, 2026, recommends no advisory. |
| Swim Beach | Caution advisory, last posted Aug 29, 2024. No all-clear recorded. |
| San Moritz | Caution advisory, last posted Jul 19, 2024. No all-clear recorded. |
| Spot not described | Caution advisory, last posted Jul 9, 2021. No all-clear recorded. |
| Lake Gregory | Caution advisory, last posted Aug 31, 2020. No all-clear recorded. |
| Lake Gregory | Reports on file, with no advisory level the state has classified. |
Advisory history
Every advisory record the state has published for Lake Gregory, 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 3, 2026 | Dam | None | Advisory based on visual and toxins |
| Aug 5, 2026 | Whole Lake | None | Lake-wide advisory |
| Aug 5, 2026 | Whole Lake | None | Lake-wide advisory |
| Aug 5, 2026 | Whole Lake | Caution | Lake-wide advisory; Under investigation |
| Aug 5, 2026 | Whole Lake | Caution | Lake-wide advisory; Under investigation |
| Jul 3, 2026 | Dam | None | Advisory based on visual and toxins |
| May 18, 2026 | Dam | None | Advisory based on visual and toxins |
| Jul 16, 2025 | Dam | Caution | Advisory based on visual and toxins |
| Aug 29, 2024 | Swim Beach | Caution | Lake-wide advisory |
| Aug 29, 2024 | Swim Beach | Caution | Lake-wide advisory |
| Jul 19, 2024 | San Moritz | Caution | Lake-wide advisory; Under investigation |
| Jul 19, 2024 | Swim Beach | Caution | Lake-wide advisory; Under investigation |
| Jun 27, 2024 | Swim Beach | Caution | Lake-wide advisory; Under investigation |
| Jun 27, 2024 | San Moritz | Caution | Lake-wide advisory; Under investigation |
| Jun 27, 2024 | Swim Beach | Caution | Lake-wide advisory; Under investigation |
| Jun 27, 2024 | Dam | Caution | Lake-wide advisory; Under investigation |
| Jun 25, 2024 | San Moritz | Caution | Lake-wide advisory; Under investigation |
| Jun 25, 2024 | Swim Beach | Caution | Lake-wide advisory; Under investigation |
| Jun 25, 2024 | Swim Beach | Caution | Lake-wide advisory; visual monitoring based advisory; Visual monitoring only-present bloom |
| Aug 23, 2023 | Dam | Caution | Lake-wide advisory; Under investigation |
| Aug 23, 2023 | Dam | None | Testing results below posting triggers |
| Jun 29, 2023 | Dam | None | Testing results below posting triggers |
| Jun 29, 2023 | Dam | None | Testing results below posting triggers |
| Sep 2, 2022 | San Moritz | None | No cyano bloom w/testing |
| Sep 2, 2022 | Dam | None | Testing results below posting triggers |
| Sep 2, 2022 | San Moritz | None | No cyano bloom w/testing |
| Sep 2, 2022 | Dam | None | Testing results below posting triggers |
| Sep 2, 2022 | Swim Beach | None | No cyano bloom w/testing |
| Aug 19, 2022 | Swim Beach | Caution | Suspected illness reported |
| Aug 19, 2022 | Swim Beach | None | Suspected illness report closed |
| Aug 18, 2022 | Swim Beach | Caution | Suspected illness reported; Under investigation |
| Jun 30, 2022 | Swim Beach | None | Testing results below posting triggers |
| May 17, 2022 | Swim Beach | None | No cyano bloom w/testing |
| Jul 9, 2021 | Spot not described | Caution | Advisory based on visual and toxins |
| Aug 31, 2020 | Lake Gregory | Caution | Advisory based on visual and toxins |
| Aug 31, 2018 | Lake Gregory | NA - refer to Report Details |
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.