Spring Lake: toxic algae advisories
Spring Lake, Sonoma County. See all Sonoma County waters.
What the state's records say
Visual observation, last posted May 29, 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: The state recorded an advisory of a type outside the Caution, Warning and Danger levels. Read the sign posted at the water.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Spring Lake
The state has an advisory on file for Spring Lake (Visual observation), last posted May 29, 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 |
|---|---|
| lagoon area east side of lake | Reports on file, with no advisory level the state has classified. |
| near connection to Lake Ralphine | Visual observation, last posted May 29, 2026. No all-clear recorded. |
| Lakewide | Algal mat general awareness sign, last posted Aug 14, 2023. No all-clear recorded. |
| Lakewide | The state's latest record, from Nov 7, 2022, recommends no advisory. |
Advisory history
Every advisory record the state has published for Spring 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 9, 2026 | lagoon area east side of lake | NA - refer to Report Details | Under investigation |
| May 29, 2026 | near connection to Lake Ralphine | Visual observation | Under investigation |
| Aug 14, 2023 | Lakewide | Algal mat general awareness sign | Bottom/benthic bloom observed; Rec algal mat general awareness; Testing results below posting triggers |
| Aug 3, 2023 | Lakewide | Algal mat general awareness sign | Bottom/benthic bloom observed; Rec algal mat general awareness; Under investigation |
| Nov 7, 2022 | Lakewide | None | End date recorded: Nov 7, 2022. De-posting advisory.; visual monitoring based advisory |
| Nov 7, 2022 | Lakewide | None | De-posting advisory.; visual monitoring based advisory |
| Jul 18, 2022 | Lakewide | Algal mat alert sign | Alert-detached mats observed |
| Jul 18, 2022 | Lakewide | Algal mat alert sign | Alert-detached mats observed |
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.