Muddy Hollow Creek: toxic algae advisories
Muddy Hollow 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 Muddy Hollow Creek
The state's latest record, from Jun 11, 2026, recommends no advisory. For Muddy Hollow 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 |
|---|---|
| ~0.3mi above Pt. Reyas Ntl. Seashore Rd. (201MUD500) | The state's latest record, from Jun 11, 2026, recommends no advisory. |
Advisory history
Every advisory record the state has published for Muddy Hollow 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 | ~0.3mi above Pt. Reyas Ntl. Seashore Rd. (201MUD500) | 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.