Lake Del Valle: toxic algae advisories
Lake Del Valle, Alameda County. See all Alameda County waters.
What the state's records say
Danger advisory, last posted Oct 16, 2026. No all-clear recorded.
9 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: Toxins may be at levels that can seriously harm people and animals. Stay out of the water and keep children and pets away from the water and the shore.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Lake Del Valle
The state has an advisory on file for Lake Del Valle (Danger 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.
Satellite estimate (not an advisory)
Week ending May 16, 2026: about 140,000 cells/mL of cyanobacteria near the center of Lake del Valle.
A satellite estimate from EPA CyAN for a 2.8 km² lake. It does not measure toxins and does not change the advisory status.
| Week ending | Estimate |
|---|---|
| May 16, 2026 | about 140,000 cells/mL |
| Jan 10, 2026 | about 300,000 cells/mL |
| Apr 26, 2025 | about 260,000 cells/mL |
| Apr 5, 2025 | about 910,000 cells/mL |
| Apr 6, 2024 | about 1,700,000 cells/mL |
| Mar 30, 2024 | about 1,200,000 cells/mL |
| Mar 16, 2024 | about 500,000 cells/mL |
| Mar 9, 2024 | about 940,000 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 |
|---|---|
| boat launch | Caution advisory, last posted Oct 16, 2026. No all-clear recorded. |
| East Beach | Caution advisory, last posted Oct 9, 2026. No all-clear recorded. |
| West Beach | Caution advisory, last posted Sep 18, 2026. No all-clear recorded. |
| Lake Del Valle | The state's latest record, from Jul 3, 2024, recommends no advisory. |
| Lake Del Valle East Beach | The state recorded an end date of Dec 31, 2022. |
| Lake Del Valle West Beach | The state recorded an end date of Dec 31, 2022. |
| Lake Del Valle | Caution advisory, last posted Aug 23, 2022. No all-clear recorded. |
| Spot not described | Caution advisory, last posted Apr 15, 2022. No all-clear recorded. |
| Spot not described | The state's latest record, from Sep 13, 2021, recommends no advisory. |
| Spot not described | Caution advisory, last posted Jul 16, 2021. No all-clear recorded. |
| Spot not described | The state's latest record, from Jun 16, 2021, recommends no advisory. |
| Lake Del Valle | Danger advisory, last posted Dec 31, 2020. No all-clear recorded. |
| Lake del Valle | The state's latest record, from Mar 9, 2018, recommends no advisory. |
| Lake Del Valle | Danger advisory, last posted Aug 31, 2017. No all-clear recorded. |
| Lake del Valle | Warning advisory, last posted Aug 31, 2017. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Lake Del Valle, 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 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 9, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 9, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 1, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 25, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 18, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 18, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 18, 2026 | West Beach | Caution | Visual monitoring only-present bloom |
| Sep 18, 2026 | West Beach | Caution | Visual monitoring only-present bloom |
| Sep 11, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 11, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 11, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 8, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 8, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 8, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 31, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 31, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 31, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 21, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 21, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 14, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 14, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 14, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 7, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 7, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 7, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 31, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 31, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 31, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 31, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 24, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 17, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 17, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 17, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 10, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 10, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 3, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 3, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 26, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 26, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 26, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 19, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 19, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 12, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 12, 2026 | West Beach | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 5, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 5, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 5, 2026 | West Beach | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 5, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 1, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 1, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 22, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 22, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 15, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 15, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 15, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 15, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 8, 2026 | West Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 8, 2026 | East Beach | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 1, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 24, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 24, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 16, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 10, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 27, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 20, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 13, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 6, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 26, 2026 | boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 20, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 6, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 30, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 23, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 16, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 9, 2026 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 19, 2025 | East Beach | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 19, 2025 | West Beach | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 19, 2025 | boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 5, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Nov 20, 2025 | boat launch | Danger | Updates from routine monitoring program-organization |
| Nov 7, 2025 | boat launch | Danger | Updates from routine monitoring program-organization |
| Oct 31, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Oct 31, 2025 | East Beach | Danger | Updates from routine monitoring program-organization |
| Oct 23, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Oct 23, 2025 | East Beach | Danger | Updates from routine monitoring program-organization |
| Oct 17, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Oct 17, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Oct 10, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Oct 10, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 26, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 26, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 19, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 19, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 12, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 12, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 5, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 5, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Aug 29, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Aug 29, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 22, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 22, 2025 | East Beach | Danger | Updates from routine monitoring program-organization |
| Aug 18, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Aug 8, 2025 | East Beach | Danger | Updates from routine monitoring program-organization |
| Aug 8, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Aug 8, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 31, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Jul 31, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 24, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 24, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Jul 18, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Jul 18, 2025 | East Beach | None | Updates from routine monitoring program-organization |
| Jul 11, 2025 | East Beach | None | Updates from routine monitoring program-organization |
| Jul 11, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Jul 2, 2025 | boat launch | None | Updates from routine monitoring program-organization |
| Jun 26, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Jun 26, 2025 | East Beach | None | Updates from routine monitoring program-organization |
| Jun 20, 2025 | East Beach | None | Updates from routine monitoring program-organization |
| Jun 20, 2025 | West Beach | None | Updates from routine monitoring program-organization |
| Jun 13, 2025 | East Beach | None | Updates from routine monitoring program-organization |
| Jun 13, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Jun 13, 2025 | East Beach | None | Updates from routine monitoring program-organization |
| Jun 13, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Jun 13, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Jun 6, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| Jun 6, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Jun 2, 2025 | West Beach | Caution | Updates from routine monitoring program-organization |
| Jun 2, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| May 19, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| May 19, 2025 | West Beach | Danger | Updates from routine monitoring program-organization |
| May 9, 2025 | West Beach | Danger | Updates from routine monitoring program-organization |
| May 9, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| May 2, 2025 | East Beach | Caution | Updates from routine monitoring program-organization |
| May 2, 2025 | West Beach | Danger | Updates from routine monitoring program-organization |
| Apr 28, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Apr 23, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Apr 11, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Mar 21, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Mar 14, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Mar 7, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Feb 28, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Feb 21, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Feb 6, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Jan 31, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Jan 24, 2025 | boat launch | Caution | Updates from routine monitoring program-organization |
| Jan 13, 2025 | boat launch | None | Updates from routine monitoring program-organization |
| Dec 20, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Dec 6, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Nov 20, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Nov 12, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Oct 31, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Oct 18, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Oct 11, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Oct 4, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Sep 27, 2024 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 27, 2024 | East Beach | None | Updates from routine monitoring program-organization |
| Sep 20, 2024 | East Beach | None | Updates from routine monitoring program-organization |
| Sep 20, 2024 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 13, 2024 | West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 13, 2024 | East Beach | None | Updates from routine monitoring program-organization |
| Sep 6, 2024 | East Beach | None | Updates from routine monitoring program-organization |
| Sep 6, 2024 | West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 30, 2024 | boat launch | None | Updates from routine monitoring program-organization |
| Aug 30, 2024 | West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 30, 2024 | East Beach | None | Updates from routine monitoring program-organization |
| Aug 15, 2024 | East Beach | None | |
| Aug 15, 2024 | West Beach | Caution | |
| Aug 5, 2024 | West Beach | Caution | |
| Aug 5, 2024 | East Beach | None | |
| Aug 2, 2024 | East Beach | None | |
| Aug 2, 2024 | West Beach | Caution | |
| Jul 26, 2024 | West Beach | Caution | |
| Jul 26, 2024 | East Beach | None | |
| Jul 22, 2024 | East Beach | None | |
| Jul 22, 2024 | West Beach | Caution | |
| Jul 3, 2024 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 3, 2024 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 29, 2024 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 24, 2024 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 14, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 14, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 6, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 29, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 23, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 16, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 10, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 2, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 25, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 19, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 12, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 8, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 1, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 20, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 14, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 9, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 29, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 19, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 2, 2024 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 26, 2023 | Lake Del Valle | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 19, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 4, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 28, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 14, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 31, 2023 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 24, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 17, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 17, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 10, 2023 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 2, 2023 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 26, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 19, 2023 | Lake Del Valle | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 11, 2023 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 5, 2023 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 29, 2023 | Lake Del Valle | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 29, 2023 | Lake Del Valle | None | Updates from routine monitoring program-organization |
| Aug 22, 2023 | Lake Del Valle | None | |
| Aug 15, 2023 | Lake Del Valle | None | |
| Aug 10, 2023 | Lake Del Valle | None | |
| Aug 1, 2023 | Lake Del Valle | None | |
| Jul 25, 2023 | Lake Del Valle | None | |
| Jul 18, 2023 | Lake Del Valle | Caution | |
| Jul 11, 2023 | Lake Del Valle | Caution | |
| Jul 3, 2023 | Lake Del Valle | Caution | |
| Jun 27, 2023 | Lake Del Valle | Caution | |
| Jun 20, 2023 | Lake Del Valle | Caution | |
| Jun 5, 2023 | Lake Del Valle | Caution | |
| May 30, 2023 | Lake Del Valle | Caution | |
| May 23, 2023 | Lake Del Valle | Caution | |
| May 16, 2023 | Lake Del Valle | Caution | |
| May 10, 2023 | Lake Del Valle | Caution | |
| May 2, 2023 | Lake Del Valle | Caution | |
| Apr 26, 2023 | Lake Del Valle | Caution | |
| Apr 20, 2023 | Lake Del Valle | Caution | |
| Apr 12, 2023 | Lake Del Valle | Caution | |
| Apr 4, 2023 | Lake Del Valle | Caution | |
| Mar 30, 2023 | Lake Del Valle | Caution | |
| Mar 8, 2023 | Lake Del Valle | Caution | |
| Feb 15, 2023 | Lake Del Valle | Caution | |
| Feb 15, 2023 | Lake Del Valle | Caution | |
| Feb 8, 2023 | Lake Del Valle | Warning | |
| Feb 1, 2023 | Lake Del Valle | Warning | |
| Jan 24, 2023 | Lake Del Valle | Danger | |
| Dec 29, 2022 | Lake Del Valle | Blank in the state's file | |
| Dec 29, 2022 | Lake Del Valle East Beach | Danger | End date recorded: Dec 31, 2022. Updates from routine monitoring program-organization |
| Dec 29, 2022 | Lake Del Valle East Beach | Danger | Updates from routine monitoring program-organization |
| Dec 20, 2022 | Lake Del Valle East Beach | Danger | Updates from routine monitoring program-organization |
| Dec 5, 2022 | Lake Del Valle East Beach | Danger | Updates from routine monitoring program-organization |
| Nov 29, 2022 | Lake Del Valle East Beach | Danger | Updates from routine monitoring program-organization |
| Nov 22, 2022 | Lake Del Valle West Beach | Danger | End date recorded: Dec 31, 2022. Updates from routine monitoring program-organization |
| Nov 22, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Nov 22, 2022 | Lake Del Valle East Beach | Danger | Updates from routine monitoring program-organization |
| Nov 15, 2022 | Lake Del Valle East Beach | Danger | Updates from routine monitoring program-organization |
| Oct 25, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Oct 18, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Oct 12, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Oct 7, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Oct 7, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Oct 7, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Oct 4, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Oct 4, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 20, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 20, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 13, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 13, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 9, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Sep 9, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Sep 9, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 30, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Aug 30, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 23, 2022 | Lake Del Valle | Caution | Updates from routine monitoring program-organization |
| Aug 23, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Aug 23, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Aug 9, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Aug 9, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Aug 1, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Aug 1, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Jul 27, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 27, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Jul 26, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 26, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Jul 22, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 22, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Jul 19, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 19, 2022 | Lake Del Valle West Beach | Caution | Updates from routine monitoring program-organization |
| Jul 15, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Jul 15, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 15, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Jul 8, 2022 | Lake Del Valle East Beach | Caution | Updates from routine monitoring program-organization |
| Jul 8, 2022 | Lake Del Valle West Beach | Danger | Updates from routine monitoring program-organization |
| Jun 22, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| Jun 21, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| Jun 14, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| Jun 10, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| Jun 6, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| May 31, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| May 27, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| May 17, 2022 | Lake Del Valle | Danger | Updates from routine monitoring program-organization |
| May 17, 2022 | Lake Del Valle | Danger | |
| May 10, 2022 | Lake Del Valle | Danger | |
| May 2, 2022 | Lake Del Valle | Danger | |
| Apr 15, 2022 | Spot not described | Caution | Advisory based on visual and toxins |
| Sep 13, 2021 | Spot not described | None | Suspected illness report closed |
| Jul 16, 2021 | Spot not described | Caution | Advisory based on visual and toxins |
| Jun 16, 2021 | Spot not described | None | Testing results below posting triggers |
| Dec 31, 2020 | Lake Del Valle | Danger | Advisory based on visual and toxins |
| Mar 9, 2018 | Lake del Valle | None | |
| Aug 31, 2017 | Lake Del Valle | Danger | |
| Aug 31, 2017 | Lake del Valle | Warning |
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.