Santa Ana River: toxic algae advisories
Santa Ana River, San Bernardino County. See all San Bernardino County waters.
What the state's records say
Algal mat general awareness sign, last posted Sep 25, 2026. 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 Santa Ana River
The state has an advisory on file for Santa Ana River (Algal mat general awareness sign), last posted Sep 25, 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 |
|---|---|
| Downstream from CA-38 Bridge | Algal mat general awareness sign, last posted Sep 25, 2026. No all-clear recorded. |
| Santa Ana River SF ~3.5mi above Mainstem | The state's latest record, from May 20, 2022, recommends no advisory. |
Advisory history
Every advisory record the state has published for Santa Ana River, 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 25, 2026 | Downstream from CA-38 Bridge | Algal mat general awareness sign | Advisory based on visual and toxins |
| May 20, 2022 | Santa Ana River SF ~3.5mi above Mainstem | None | End date recorded: May 19, 2022. No cyano bloom w/testing |
| May 20, 2022 | Santa Ana River SF ~3.5mi above Mainstem | None | End date recorded: May 19, 2022. No cyano bloom w/testing |
| May 20, 2022 | Santa Ana River SF ~3.5mi above Mainstem | None | No cyano bloom w/testing |
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.