New Bullards Bar Reservoir: toxic algae advisories
New Bullards Bar Reservoir, Yuba County. See all Yuba County waters.
What the state's records say
Caution advisory, last posted Jul 26, 2024. 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 New Bullards Bar Reservoir
The state has an advisory on file for New Bullards Bar Reservoir (Caution advisory), last posted Jul 26, 2024, 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 Oct 25, 2025: about 7,700 cells/mL of cyanobacteria near the center of New Bullards Bar Reservoir.
A satellite estimate from EPA CyAN for a 16.3 km² lake. It does not measure toxins and does not change the advisory status.
| Week ending | Estimate |
|---|---|
| Oct 25, 2025 | about 7,700 cells/mL |
| Jan 11, 2025 | about 49,000 cells/mL |
| Feb 3, 2024 | about 9,300 cells/mL |
| Dec 16, 2023 | about 12,000 cells/mL |
| Nov 4, 2023 | about 31,000 cells/mL |
| Dec 3, 2022 | about 11,000 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 |
|---|---|
| New Bullards Bar Dam | Reports on file, with no advisory level the state has classified. |
| North Yuba Confluence with New Bullards Bar Reservoir | Caution advisory, last posted Jul 26, 2024. No all-clear recorded. |
Advisory history
Every advisory record the state has published for New Bullards Bar 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 |
|---|---|---|---|
| Sep 22, 2026 | New Bullards Bar Dam | NA - refer to Report Details | Under investigation |
| Jul 26, 2024 | North Yuba Confluence with New Bullards Bar Reservoir | Caution | Under investigation; Visual monitoring only-present bloom |
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.