Harveston Lake: toxic algae advisories
Harveston Lake, San Diego County. See all San Diego County waters.
What the state's records say
The state's latest record, from Nov 3, 2025, recommends no advisory.
That reflects what the state knew on that date. It is not a finding that the water is safe now: blooms can return within days, and many are never reported.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Harveston Lake
The state's latest record, from Nov 3, 2025, recommends no advisory. For Harveston Lake, that is not the same as an all-clear for today. Look at the water before your dog goes in: keep it out of green, blue-green or scummy water and away from mats on the shore.
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 in community of Temecula, CA | The state's latest record, from Nov 3, 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 |
|---|---|---|---|
| Nov 3, 2025 | lake in community of Temecula, CA | None | Suspected bloom, investigation ongoing |
| Apr 5, 2024 | lake in community of Temecula, CA | None | Rec general awareness |
| Mar 29, 2024 | lake in community of Temecula, CA | NA - refer to Report Details | Under investigation |
| Mar 29, 2024 | lake in community of Temecula, CA | None | Under investigation |
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.