Laguna Lake: toxic algae advisories
Laguna Lake, San Luis Obispo County. See all San Luis Obispo County waters.
What the state's records say
Caution advisory, last posted Sep 4, 2026. No all-clear recorded.
5 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 Laguna Lake
The state has an advisory on file for Laguna Lake (Caution advisory), last posted Sep 4, 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 |
|---|---|
| at dock near Lake Side Trail (310LAGDOC) | General awareness, last posted Sep 4, 2026. No all-clear recorded. |
| Spot not described | The state's latest record, from May 27, 2021, recommends no advisory. |
| Laguna Lake Park Dock near launch ramp at end of Lake Side Trail | Caution advisory, last posted Oct 21, 2020. No all-clear recorded. |
| Laguna Lake near culvert on Madonna Rd. | Caution advisory, last posted Oct 21, 2020. No all-clear recorded. |
| Laguna Lake Fishing Dock near picnic area | Caution advisory, last posted Oct 21, 2020. No all-clear recorded. |
| Laguna Lake | Caution advisory, last posted Sep 3, 2020. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Laguna 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 |
|---|---|---|---|
| Sep 4, 2026 | at dock near Lake Side Trail (310LAGDOC) | General awareness | Advisory based on visual and toxins |
| Sep 4, 2026 | at dock near Lake Side Trail (310LAGDOC) | None | Advisory based on visual and toxins |
| Aug 4, 2026 | at dock near Lake Side Trail (310LAGDOC) | General awareness | Testing results below posting triggers |
| Jun 25, 2026 | at dock near Lake Side Trail (310LAGDOC) | General awareness | Testing results below posting triggers |
| May 22, 2026 | at dock near Lake Side Trail (310LAGDOC) | None | Testing results below posting triggers |
| May 22, 2026 | at dock near Lake Side Trail (310LAGDOC) | General awareness | Testing results below posting triggers |
| Aug 28, 2025 | at dock near Lake Side Trail (310LAGDOC) | None | Testing results below posting triggers |
| Jul 30, 2025 | at dock near Lake Side Trail (310LAGDOC) | None | Testing results below posting triggers |
| Jun 30, 2025 | at dock near Lake Side Trail (310LAGDOC) | None | Testing results below posting triggers |
| May 15, 2025 | at dock near Lake Side Trail (310LAGDOC) | None | Testing results below posting triggers |
| Aug 26, 2024 | at dock near Lake Side Trail (310LAGDOC) | None | Testing results below posting triggers |
| Jun 28, 2024 | at dock near Lake Side Trail (310LAGDOC) | None | Advisory based on visual and toxins; Updates from routine monitoring program-organization |
| May 21, 2024 | at dock near Lake Side Trail (310LAGDOC) | None | Advisory based on visual and toxins; Updates from routine monitoring program-organization |
| Aug 31, 2023 | at dock near Lake Side Trail (310LAGDOC) | Caution | Advisory based on visual and toxins; Updates from routine monitoring program-organization |
| Aug 7, 2023 | at dock near Lake Side Trail (310LAGDOC) | Caution | Advisory based on visual and toxins |
| Aug 7, 2023 | at dock near Lake Side Trail (310LAGDOC) | Caution | Advisory based on visual and toxins |
| Jun 29, 2023 | at dock near Lake Side Trail (310LAGDOC) | NA - refer to Report Details | Rec general awareness |
| May 25, 2023 | at dock near Lake Side Trail (310LAGDOC) | NA - refer to Report Details | Rec general awareness |
| Dec 9, 2022 | at dock near Lake Side Trail (310LAGDOC) | None | Updates from routine monitoring program-organization |
| Nov 28, 2022 | at dock near Lake Side Trail (310LAGDOC) | None | Updates from routine monitoring program-organization |
| Nov 10, 2022 | at dock near Lake Side Trail (310LAGDOC) | Algal mat alert sign | Alert-detached mats observed; Bottom/benthic bloom observed |
| Oct 19, 2022 | at dock near Lake Side Trail (310LAGDOC) | General awareness | Rec general awareness |
| Sep 1, 2022 | at dock near Lake Side Trail (310LAGDOC) | Caution | Advisory based on visual and toxins |
| Jun 30, 2022 | at dock near Lake Side Trail (310LAGDOC) | Caution | visual monitoring based advisory |
| May 26, 2022 | at dock near Lake Side Trail (310LAGDOC) | Caution | visual monitoring based advisory |
| May 27, 2021 | Spot not described | None | Testing results below posting triggers |
| Oct 21, 2020 | Laguna Lake Park Dock near launch ramp at end of Lake Side Trail | Caution | Advisory based on visual and toxins |
| Oct 21, 2020 | Laguna Lake near culvert on Madonna Rd. | Caution | Advisory based on visual and toxins |
| Oct 21, 2020 | Laguna Lake Fishing Dock near picnic area | Caution | Advisory based on visual and toxins |
| Sep 3, 2020 | Laguna Lake | Caution | Advisory based on visual and toxins |
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.