Shadow Cliffs Lake: toxic algae advisories
Shadow Cliffs Lake, Alameda County. See all Alameda County waters.
What the state's records say
Caution advisory, last posted Oct 16, 2026. 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 Shadow Cliffs Lake
The state has an advisory on file for Shadow Cliffs Lake (Caution advisory), last posted Oct 16, 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.
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 |
|---|---|
| Shadow Cliffs Reservoir lake-wide | Caution advisory, last posted Oct 16, 2026. No all-clear recorded. |
| Shadow Cliffs Reservoir lake-wide | The state's latest record, from Dec 29, 2022, recommends no advisory. |
| & Arroyo - dog access area | The state's latest record, from Apr 15, 2022, recommends no advisory. |
| Shadow Cliffs Reservoir | The state's latest record, from Mar 11, 2022, recommends no advisory. |
| Shadow Cliffs Lake | The state's latest record, from Jul 16, 2021, recommends no advisory. |
| Shadow Cliffs Reservoir & Arroyo - dog access area | The state's latest record, from Jul 16, 2021, recommends no advisory. |
| Shadow Cliffs Lake | The state's latest record, from Aug 31, 2017, recommends no advisory. |
Advisory history
Every advisory record the state has published for Shadow Cliffs 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 16, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 9, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 1, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 25, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 18, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 11, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 3, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 31, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 21, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 14, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 7, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 31, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 24, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 17, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 10, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 3, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 26, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 19, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 12, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 5, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 1, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 22, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 15, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 8, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 1, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 24, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 16, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 16, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 10, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 27, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 20, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 13, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 6, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 20, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 6, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 30, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 9, 2026 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 12, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 5, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 20, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 7, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 31, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 23, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 17, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 10, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 26, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 19, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 12, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 5, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 29, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 22, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 18, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 8, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 31, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 24, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 18, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 26, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 20, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 13, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 13, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 6, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 2, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 19, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 9, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 2, 2025 | Shadow Cliffs Reservoir lake-wide | Algal mat alert sign | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 2, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 28, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 23, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 11, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 4, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 21, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 14, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 7, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 28, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 21, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 6, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jan 31, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jan 24, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jan 17, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jan 13, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jan 2, 2025 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Dec 20, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Dec 12, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Dec 6, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Nov 20, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Nov 12, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 31, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 18, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 11, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 4, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Sep 27, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Sep 20, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Sep 13, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Sep 6, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Aug 26, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Aug 15, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Aug 2, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Aug 2, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jul 22, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jul 22, 2024 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 25, 2024 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 25, 2024 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 21, 2024 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 21, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 4, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 29, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 24, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 14, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| May 6, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Apr 29, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Apr 23, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Apr 16, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Apr 9, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Apr 2, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Mar 25, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Mar 19, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Mar 12, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Mar 8, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Mar 1, 2024 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Feb 20, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Feb 14, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Feb 9, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Jan 29, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Jan 19, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Jan 11, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Jan 2, 2024 | Shadow Cliffs Reservoir lake-wide | Danger | Updates from routine monitoring program-organization |
| Dec 19, 2023 | Shadow Cliffs Reservoir lake-wide | Warning | Updates from routine monitoring program-organization |
| Dec 19, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Dec 6, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Nov 28, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Nov 14, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 31, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 24, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 17, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Oct 10, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Oct 2, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Sep 26, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Sep 19, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Sep 15, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Sep 5, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Aug 29, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Aug 22, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Aug 15, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Aug 10, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Aug 3, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 25, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 18, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 11, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 3, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 5, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 5, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jun 5, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 31, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 24, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 18, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 10, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Apr 25, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Apr 12, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Apr 4, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Mar 30, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Feb 1, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Feb 1, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Feb 1, 2023 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jan 24, 2023 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Dec 29, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Dec 29, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Dec 20, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Dec 20, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Dec 7, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Nov 22, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Nov 22, 2022 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Oct 18, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Oct 4, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Aug 23, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Aug 19, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Aug 16, 2022 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jul 26, 2022 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jul 22, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 6, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 6, 2022 | Shadow Cliffs Reservoir lake-wide | Caution | Updates from routine monitoring program-organization |
| Jul 6, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jul 1, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 22, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 14, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 6, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Jun 6, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 24, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 24, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 18, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| May 6, 2022 | Shadow Cliffs Reservoir lake-wide | None | Updates from routine monitoring program-organization |
| Apr 15, 2022 | & Arroyo - dog access area | None | Testing results below posting triggers |
| Mar 11, 2022 | Shadow Cliffs Reservoir | None | Testing results below posting triggers |
| Jul 16, 2021 | Shadow Cliffs Lake | None | Testing results below posting triggers |
| Jul 16, 2021 | Shadow Cliffs Reservoir & Arroyo - dog access area | None | Testing results below posting triggers |
| Aug 31, 2017 | Shadow Cliffs Lake | 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.