Arroyo Hondo Creek: toxic algae advisories
Arroyo Hondo Creek, Marin County. See all Marin County waters.
What the state's records say
The state's latest record, from Jun 11, 2026, recommends no advisory.
That reflects what the state knew on that date. It is not a finding that the water is safe now: blooms can return within days, and many are never reported.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Arroyo Hondo Creek
The state's latest record, from Jun 11, 2026, recommends no advisory. For Arroyo Hondo Creek, that is not the same as an all-clear for today. Look at the water before your dog goes in: keep it out of green, blue-green or scummy water and away from mats on the shore.
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 |
|---|---|
| in Point Reyes National Seashore, 200m DS of confluence of two tribs (201AHO350) | The state's latest record, from Jun 11, 2026, recommends no advisory. |
Advisory history
Every advisory record the state has published for Arroyo Hondo Creek, 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 |
|---|---|---|---|
| Jun 11, 2026 | in Point Reyes National Seashore, 200m DS of confluence of two tribs (201AHO350) | None |
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.