Lake San Marcos: toxic algae advisories
Lake San Marcos, San Diego County. See all San Diego County waters.
What the state's records say
Warning advisory, last posted Jul 14, 2023. No all-clear recorded.
5 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: Toxins may be at levels that can harm people and animals. Do not swim or let children or pets in the water, and stay away from scum.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Lake San Marcos
The state has an advisory on file for Lake San Marcos (Warning advisory), last posted Jul 14, 2023, 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 San Marcos | Warning advisory, last posted Jul 14, 2023. No all-clear recorded. |
| Lake San Marcos | General awareness, last posted Jun 9, 2022. No all-clear recorded. |
| Spot not described | Caution advisory, last posted May 25, 2021. No all-clear recorded. |
| Lake San Marcos, near Lakehouse Hotel | Caution advisory, last posted Jun 4, 2019. No all-clear recorded. |
| Lake San Marcos | Caution advisory, last posted Jul 21, 2017. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Lake San Marcos, 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 |
|---|---|---|---|
| Jul 14, 2023 | Lake San Marcos | Warning | Suspected bloom, investigation ongoing |
| Jun 9, 2022 | Lake San Marcos | General awareness | Floating/planktonic bloom observed |
| May 25, 2021 | Spot not described | Caution | visual monitoring based advisory |
| Jun 4, 2019 | Lake San Marcos, near Lakehouse Hotel | Caution | |
| Jul 21, 2017 | Lake San Marcos | Caution |
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.