Harveston Lake: toxic algae advisories
Harveston Lake, Riverside County. See all Riverside County waters.
What the state's records say
Caution advisory, last posted Aug 31, 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: 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 Harveston Lake
The state has an advisory on file for Harveston Lake (Caution advisory), last posted Aug 31, 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 |
|---|---|
| lake-wide | Caution advisory, last posted Aug 31, 2026. No all-clear recorded. |
| lake-wide | Caution advisory, last posted Jun 18, 2026. No all-clear recorded. |
| Harveston Lakehouse | The state's latest record, from Nov 19, 2025, recommends no advisory. |
Advisory history
Every advisory record the state has published for Harveston 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 |
|---|---|---|---|
| Aug 31, 2026 | lake-wide | Caution | Advisory based on visual and toxins |
| Aug 20, 2026 | lake-wide | Warning | Visual monitoring only-present bloom |
| Jun 18, 2026 | lake-wide | Caution | Advisory based on visual and toxins |
| Jun 3, 2026 | lake-wide | Caution | Advisory based on visual and toxins |
| May 19, 2026 | lake-wide | Danger | Advisory based on visual and toxins |
| May 12, 2026 | lake-wide | Caution | visual monitoring based advisory |
| Nov 19, 2025 | Harveston Lakehouse | None | End date recorded: Nov 19, 2025. No cyano bloom w/testing |
| Nov 13, 2025 | Harveston Lakehouse | Caution | Lake-wide advisory; Suspected illness reported |
| Nov 4, 2025 | Harveston Lakehouse | Caution | Lake-wide advisory; Suspected illness reported |
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.