Sonoma Creek: toxic algae advisories
Sonoma Creek, Sonoma County. See all Sonoma County waters.
What the state's records say
Algal mat alert sign, last posted Aug 18, 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 Sonoma Creek
The state has an advisory on file for Sonoma Creek (Algal mat alert sign), last posted Aug 18, 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 Maxwell Farms Regional Park (206SON050) | Algal mat alert sign, last posted Aug 18, 2026. No all-clear recorded. |
| near Fetter Hot Springs (206SON090) | Algal mat alert sign, last posted Aug 18, 2026. No all-clear recorded. |
| Goodspeed Trail (206SON300) | The state's latest record, from Aug 18, 2026, recommends no advisory. |
| below Adobe Cyn. Rd. and Godspeed Trail | The state's latest record, from Sep 22, 2022, recommends no advisory. |
| below Adobe Cyn. Rd. | The state's latest record, from Jun 30, 2021, recommends no advisory. |
| below Adobe Cyn. Rd. | The state's latest record, from Jun 30, 2021, recommends no advisory. |
Advisory history
Every advisory record the state has published for Sonoma Creek, 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 |
|---|---|---|---|
| Aug 18, 2026 | at Maxwell Farms Regional Park (206SON050) | Algal mat alert sign | Updates from routine monitoring program-organization |
| Aug 18, 2026 | near Fetter Hot Springs (206SON090) | Algal mat alert sign | Updates from routine monitoring program-organization |
| Aug 18, 2026 | Goodspeed Trail (206SON300) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jun 29, 2026 | at Maxwell Farms Regional Park (206SON050) | None | Updates from routine monitoring program-organization |
| Jun 29, 2026 | near Fetter Hot Springs (206SON090) | Caution | Updates from routine monitoring program-organization |
| Jun 29, 2026 | Goodspeed Trail (206SON300) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| May 18, 2026 | at Maxwell Farms Regional Park (206SON050) | None | Updates from routine monitoring program-organization |
| May 18, 2026 | near Fetter Hot Springs (206SON090) | Caution | Updates from routine monitoring program-organization |
| Sep 25, 2025 | near Fetter Hot Springs (206SON090) | Caution | Updates from routine monitoring program-organization |
| Sep 25, 2025 | at Maxwell Farms Regional Park (206SON050) | None | Updates from routine monitoring program-organization |
| Aug 28, 2025 | at Maxwell Farms Regional Park (206SON050) | Caution | Updates from routine monitoring program-organization |
| Aug 28, 2025 | near Fetter Hot Springs (206SON090) | Caution | Updates from routine monitoring program-organization |
| Aug 28, 2024 | at Maxwell Farms Regional Park (206SON050) | Caution | Updates from routine monitoring program-organization |
| Aug 28, 2024 | near Fetter Hot Springs (206SON090) | Caution | Updates from routine monitoring program-organization |
| May 20, 2024 | at Maxwell Farms Regional Park (206SON050) | None | Updates from routine monitoring program-organization |
| May 20, 2024 | near Fetter Hot Springs (206SON090) | None | Updates from routine monitoring program-organization |
| Sep 22, 2022 | below Adobe Cyn. Rd. and Godspeed Trail | None | End date recorded: Dec 31, 2022. Testing results below posting triggers |
| Sep 22, 2022 | below Adobe Cyn. Rd. and Godspeed Trail | None | Testing results below posting triggers |
| Jul 29, 2022 | below Adobe Cyn. Rd. and Godspeed Trail | Algal mat alert sign | Bottom/benthic bloom observed |
| Jun 30, 2021 | below Adobe Cyn. Rd. | None | Testing results below posting triggers |
| Jun 30, 2021 | below Adobe Cyn. Rd. | None | Testing results below posting triggers |
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.