Grant Line Canal: toxic algae advisories
Grant Line Canal, San Joaquin County. See all San Joaquin County waters.
What the state's records say
Caution advisory, last posted Sep 17, 2026. No all-clear recorded.
3 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 Grant Line Canal
The state has an advisory on file for Grant Line Canal (Caution advisory), last posted Sep 17, 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.
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 |
|---|---|
| near Old River (GLC) | Visual observation, last posted Sep 17, 2026. No all-clear recorded. |
| East of Temporary Barrier (GLE) | Visual observation, last posted Aug 6, 2026. No all-clear recorded. |
| near Old River (GLC) | The state's latest record, from Dec 20, 2022, recommends no advisory. |
| East of Temporary Barrier (GLE) | The state's latest record, from Dec 6, 2022, recommends no advisory. |
| Grant Line Canal East of Temporary Barrier | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Grant Line Canal at Tracy Blvd Bridge | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Grant Line Canal at Old River Confluence | Caution advisory, last posted Dec 4, 2018. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Grant Line Canal, 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 17, 2026 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 21, 2026 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 6, 2026 | East of Temporary Barrier (GLE) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 5, 2026 | East of Temporary Barrier (GLE) | Visual observation | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-present bloom |
| Jul 16, 2026 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 18, 2026 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| May 27, 2026 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 29, 2026 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 15, 2026 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 12, 2025 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 20, 2025 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 16, 2025 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 24, 2025 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 24, 2025 | East of Temporary Barrier (GLE) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Aug 19, 2025 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 11, 2025 | East of Temporary Barrier (GLE) | Visual observation | Testing results below posting triggers; Updates from routine monitoring program-organization; visual monitoring based advisory |
| Aug 7, 2025 | East of Temporary Barrier (GLE) | None | Testing results below posting triggers; Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jul 30, 2025 | East of Temporary Barrier (GLE) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jul 30, 2025 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jul 25, 2025 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 30, 2025 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 12, 2025 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 12, 2025 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 3, 2025 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| May 29, 2025 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 18, 2025 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 18, 2025 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Mar 25, 2025 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 25, 2025 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Feb 19, 2025 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 19, 2025 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Dec 17, 2024 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Dec 17, 2024 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 13, 2024 | East of Temporary Barrier (GLE) | None | Testing results below posting triggers; Updates from routine monitoring program-organization; visual monitoring based advisory |
| Nov 13, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 18, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 11, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 11, 2024 | East of Temporary Barrier (GLE) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Oct 11, 2024 | East of Temporary Barrier (GLE) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Sep 13, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 16, 2024 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Aug 8, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jul 3, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 18, 2024 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 18, 2024 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| May 3, 2024 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 8, 2024 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 12, 2024 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 25, 2024 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jan 22, 2024 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 21, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Dec 8, 2023 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 8, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 14, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Oct 11, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Sep 13, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Aug 14, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 14, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 7, 2023 | near Old River (GLC) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 7, 2023 | near Old River (GLC) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 28, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 29, 2023 | East of Temporary Barrier (GLE) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 29, 2023 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 29, 2023 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 29, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 8, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 8, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 22, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization |
| Apr 18, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization |
| Mar 7, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | East of Temporary Barrier (GLE) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | East of Temporary Barrier (GLE) | None | visual monitoring based advisory |
| Jan 18, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization |
| Jan 1, 2023 | near Old River (GLC) | None | Updates from routine monitoring program-organization |
| Dec 20, 2022 | near Old River (GLC) | None | visual monitoring based advisory |
| Dec 6, 2022 | East of Temporary Barrier (GLE) | None | End date recorded: Dec 6, 2022. visual monitoring based advisory |
| Nov 9, 2022 | near Old River (GLC) | Caution | visual monitoring based advisory |
| Oct 25, 2022 | East of Temporary Barrier (GLE) | Caution | visual monitoring based advisory |
| Sep 19, 2022 | near Old River (GLC) | Caution | visual monitoring based advisory |
| Sep 15, 2022 | East of Temporary Barrier (GLE) | Caution | visual monitoring based advisory |
| Sep 15, 2022 | near Old River (GLC) | Caution | visual monitoring based advisory |
| Aug 4, 2022 | East of Temporary Barrier (GLE) | Caution | visual monitoring based advisory |
| Jul 6, 2022 | near Old River (GLC) | Caution | visual monitoring based advisory |
| Jul 6, 2022 | near Old River (GLC) | Caution | visual monitoring based advisory |
| Jul 6, 2022 | near Old River (GLC) | Caution | Updates from routine monitoring program-organization |
| Jun 3, 2022 | near Old River (GLC) | Caution | Updates from routine monitoring program-organization |
| Jun 1, 2022 | East of Temporary Barrier (GLE) | Caution | visual monitoring based advisory |
| Jun 1, 2022 | East of Temporary Barrier (GLE) | None | |
| May 3, 2022 | East of Temporary Barrier (GLE) | None | |
| Apr 13, 2022 | near Old River (GLC) | None | Updates from routine monitoring program-organization |
| Dec 4, 2018 | Grant Line Canal East of Temporary Barrier | None | |
| Dec 4, 2018 | Grant Line Canal at Tracy Blvd Bridge | None | |
| Dec 4, 2018 | Grant Line Canal at Old River Confluence | 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.