Puddingstone Reservoir: toxic algae advisories
Puddingstone Reservoir, Los Angeles County. See all Los Angeles County waters.
What the state's records say
Caution advisory, last posted May 14, 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 Puddingstone Reservoir
The state has an advisory on file for Puddingstone Reservoir (Caution advisory), last posted May 14, 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.
Satellite estimate (not an advisory)
Week ending May 23, 2026: about 650,000 cells/mL of cyanobacteria near the center of Puddingstone Reservoir.
A satellite estimate from EPA CyAN for a 1.0 km² lake. It does not measure toxins and does not change the advisory status.
| Week ending | Estimate |
|---|---|
| May 23, 2026 | about 650,000 cells/mL |
| May 16, 2026 | about 1,100,000 cells/mL |
| May 9, 2026 | about 940,000 cells/mL |
| May 2, 2026 | about 1,700,000 cells/mL |
| Apr 25, 2026 | about 710,000 cells/mL |
| Dec 13, 2025 | about 26,000 cells/mL |
| May 10, 2025 | about 350,000 cells/mL |
| May 3, 2025 | about 380,000 cells/mL |
This is a satellite estimate from the U.S. EPA's Cyanobacteria Assessment Network, not an advisory. It estimates how much cyanobacteria is in the water near the lake's center, not whether toxins are present: a high number does not mean toxins, and a low one does not mean there are none. It covers lakes of about 1 square kilometer and larger, so small ponds, dog parks and most rivers are not covered, and clouds can hide a lake for weeks. It never changes the advisory status above.
Satellite estimates: U.S. EPA Cyanobacteria Assessment Network (CyAN), from Copernicus Sentinel-3 data. Provisional, research-level estimates; EPA does not endorse this site. Checked Oct 22, 2026.
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 |
|---|---|
| Frank G. Bonelli Regional Park | The state's latest record, from Aug 27, 2026, recommends no advisory. |
| swim beach | Caution advisory, last posted May 14, 2026. No all-clear recorded. |
| swim beach | The state's latest record, from Aug 26, 2025, recommends no advisory. |
| Bonelli RV Park shore | The state's latest record, from Sep 23, 2024, recommends no advisory. |
| Bonelli RV Resort and Campground | Caution advisory, last posted May 11, 2022. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Puddingstone Reservoir, 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 27, 2026 | Frank G. Bonelli Regional Park | None | Updates from routine monitoring program-organization |
| May 14, 2026 | swim beach | Caution | Advisory based on visual and toxins; Updates from routine monitoring program-organization |
| Aug 26, 2025 | swim beach | None | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 30, 2025 | swim beach | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 18, 2025 | swim beach | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| May 20, 2025 | swim beach | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 23, 2024 | swim beach | None | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Sep 23, 2024 | Bonelli RV Park shore | None | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 16, 2024 | Bonelli RV Park shore | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Aug 16, 2024 | swim beach | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 11, 2024 | Bonelli RV Park shore | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Jun 11, 2024 | swim beach | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| May 13, 2024 | Bonelli RV Park shore | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| May 13, 2024 | swim beach | Caution | Advisory based on visual and toxins; Lake-wide advisory; Updates from routine monitoring program-organization |
| Apr 23, 2024 | Frank G. Bonelli Regional Park | Visual observation | Under investigation; Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| May 11, 2022 | Bonelli RV Resort and Campground | Caution | visual monitoring based advisory |
| May 10, 2022 | Bonelli RV Resort and Campground | NA - refer to Report Details | Suspected bloom, investigation ongoing |
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.