Castaic Lake: toxic algae advisories
Castaic Lake, Los Angeles County. See all Los Angeles County waters.
What the state's records say
Warning advisory, last posted Oct 19, 2026. No all-clear recorded.
2 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 harm people and animals. Do not swim or let children or pets in the water, and stay away from scum.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Castaic Lake
The state has an advisory on file for Castaic Lake (Warning advisory), last posted Oct 19, 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)
No satellite reading on file for Castaic 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 |
|---|---|
| Castaic Lake, outlet (surface) | Warning advisory, last posted Oct 19, 2026. No all-clear recorded. |
| Castaic Lake, boat launch | Caution advisory, last posted Oct 14, 2026. No all-clear recorded. |
| Lagoon Swim Beach | The state's latest record, from Jul 12, 2021, recommends no advisory. |
| Boat Launch | The state's latest record, from Jul 12, 2021, recommends no advisory. |
| Outlet | The state's latest record, from Jul 12, 2021, recommends no advisory. |
| Castaic Lake, Outlet | The state's latest record, from Nov 5, 2020, recommends no advisory. |
| Castaic Lake, Lagoon Swim Beach | The state's latest record, from Sep 25, 2020, recommends no advisory. |
| Castaic Lake, Boat Launch | The state's latest record, from Sep 25, 2020, recommends no advisory. |
| Castaic Lake, at Castaic Outlet (surface) | The state's latest record, from Nov 19, 2019, recommends no advisory. |
| Castaic Lake, Boat Launch | The state's latest record, from Nov 19, 2019, recommends no advisory. |
| Castaic Lake at Castaic Outlet | The state's latest record, from Aug 14, 2017, recommends no advisory. |
Advisory history
Every advisory record the state has published for Castaic 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 19, 2026 | Castaic Lake, outlet (surface) | Warning | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 14, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 14, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 30, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 30, 2026 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Sep 17, 2026 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Aug 24, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 24, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 11, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 11, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 28, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 28, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 28, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 28, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 15, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 15, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 8, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 8, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 8, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 30, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 30, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 23, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 23, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 23, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 23, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 23, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 9, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 1, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 1, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 1, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| May 4, 2026 | Castaic Lake, outlet (surface) | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 20, 2026 | Castaic Lake, outlet (surface) | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 20, 2026 | Castaic Lake, boat launch | None | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 6, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Mar 6, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 19, 2026 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 19, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 11, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Feb 11, 2026 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 22, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 22, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 13, 2026 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jan 13, 2026 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 31, 2025 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 22, 2025 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 22, 2025 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 22, 2025 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 18, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Dec 11, 2025 | Castaic Lake, boat launch | Warning | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 24, 2025 | Castaic Lake, boat launch | Warning | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 14, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 8, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 8, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 30, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 30, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 19, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 16, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 3, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 25, 2025 | Castaic Lake, boat launch | Warning | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 25, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 25, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 25, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 18, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 18, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 14, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 14, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 1, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 1, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 25, 2025 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 25, 2025 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 24, 2025 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Jul 24, 2025 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Jul 18, 2025 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Jul 18, 2025 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Jul 1, 2025 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Jul 1, 2025 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Jun 26, 2025 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Jun 26, 2025 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Jun 17, 2025 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jun 17, 2025 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 10, 2025 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 10, 2025 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| May 28, 2025 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| May 28, 2025 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Dec 10, 2024 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Dec 10, 2024 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Nov 25, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 25, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 8, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 8, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 8, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 23, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 23, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 10, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 10, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 1, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 1, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 24, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 24, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 17, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 17, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 10, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 10, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 3, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 26, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 26, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 26, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 21, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 21, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 13, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 30, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 25, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 15, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 15, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 15, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 8, 2024 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jul 8, 2024 | Castaic Lake, outlet (surface) | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 21, 2024 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 12, 2024 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| May 28, 2024 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Nov 27, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Nov 27, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Nov 27, 2023 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Nov 27, 2023 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Nov 21, 2023 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Nov 21, 2023 | Castaic Lake, boat launch | Warning | Updates from routine monitoring program-organization |
| Nov 9, 2023 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Nov 9, 2023 | Castaic Lake, outlet (surface) | Warning | Alert-high concentration toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Nov 9, 2023 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 30, 2023 | Castaic Lake, boat launch | Caution | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 30, 2023 | Castaic Lake, outlet (surface) | Caution | Alert-high concentration toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 19, 2023 | Castaic Lake, outlet (surface) | Danger | Alert-high concentration toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 19, 2023 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 17, 2023 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Oct 17, 2023 | Castaic Lake, outlet (surface) | Danger | Alert-high concentration toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 29, 2023 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 27, 2023 | Castaic Lake, outlet (surface) | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 27, 2023 | Castaic Lake, boat launch | Danger | Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 20, 2023 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Sep 20, 2023 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Sep 14, 2023 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Sep 14, 2023 | Castaic Lake, outlet (surface) | Caution | Updates from routine monitoring program-organization |
| Sep 14, 2023 | Castaic Lake, boat launch | Caution | Updates from routine monitoring program-organization |
| Aug 9, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Aug 9, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Aug 8, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Aug 8, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 28, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 28, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jul 6, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jul 6, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 5, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 5, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jun 23, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 15, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jun 15, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jun 15, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 7, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 7, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jun 2, 2023 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 2, 2023 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Oct 24, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Sep 23, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Sep 23, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Sep 16, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Sep 16, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Sep 8, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Aug 26, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Aug 26, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Aug 19, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Aug 19, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Aug 11, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Aug 11, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Aug 3, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Aug 3, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 27, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jul 27, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 21, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 13, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jul 7, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jul 7, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 21, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 20, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 20, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| Jun 16, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| Jun 3, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| May 23, 2022 | Castaic Lake, outlet (surface) | None | Updates from routine monitoring program-organization |
| May 23, 2022 | Castaic Lake, boat launch | None | Updates from routine monitoring program-organization |
| May 23, 2022 | Castaic Lake, outlet (surface) | None | visual monitoring based advisory |
| May 23, 2022 | Castaic Lake, boat launch | None | visual monitoring based advisory |
| Jul 12, 2021 | Lagoon Swim Beach | None | Testing results below posting triggers |
| Jul 12, 2021 | Boat Launch | None | Testing results below posting triggers |
| Jul 12, 2021 | Outlet | None | Testing results below posting triggers |
| Nov 5, 2020 | Castaic Lake, Outlet | None | |
| Sep 25, 2020 | Castaic Lake, Lagoon Swim Beach | None | Testing results below posting triggers |
| Sep 25, 2020 | Castaic Lake, Boat Launch | None | Testing results below posting triggers |
| Nov 19, 2019 | Castaic Lake, at Castaic Outlet (surface) | None | |
| Nov 19, 2019 | Castaic Lake, Boat Launch | None | |
| Aug 14, 2017 | Castaic Lake at Castaic Outlet | 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.