Mather Regional Park: toxic algae advisories
Mather Regional Park, Sacramento County. See all Sacramento County waters.
What the state's records say
Caution advisory, last posted Sep 16, 2025. 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 Mather Regional Park
The state has an advisory on file for Mather Regional Park (Caution advisory), last posted Sep 16, 2025, 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 |
|---|---|
| Mather lake | Caution advisory, last posted Sep 16, 2025. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Mather Regional Park, 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 16, 2025 | Mather lake | Caution | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Aug 19, 2025 | Mather lake | Caution | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jul 22, 2025 | Mather lake | Caution | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jun 30, 2025 | Mather lake | None | Updates from routine monitoring program-organization |
| May 28, 2025 | Mather lake | None | Testing results below posting triggers |
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.