Is the lake safe?

Mendocino County, California

East Fork Russian River algae bloom status

No recent reports

Checked against state data on 24 October 2026

Is East Fork Russian River safe to swim in?

There are no bloom reports for East Fork Russian River in the last 30 days of California's data. The most recent was a bloom report on 9 April 2025 at above Lake Mendocino. Blooms are a recurring problem here: toxic algae has been reported every year from 2023 to 2025, most often in April, July and August.

No recent report isn't the same as safe, because most lakes are only checked occasionally. Look at the water and the signs before you swim.

Check today on the California HABs Portal map
Years with blooms
3 of 3
Usual months
Apr, Jul and Aug
Advisories issued
0
Data checked
24 October 2026
See it on the California map

East Fork Russian River algae bloom history

California's Water Boards hold 5 bloom reports for East Fork Russian River going back to 2023. Reports came in every year since then, with the busiest year being 2023 (2 reports).

None of these reports led to a formal Caution, Warning or Danger advisory. They were logged as reported blooms or awareness signs, often from members of the public.

Blooms have been recorded every year for the last 3 years in the data.

  1. 2023 2 reports
  2. 2024 1 report
  3. 2025 2 reports
Reported, no advisory level

When do algae blooms happen at East Fork Russian River?

At East Fork Russian River, reports are most often logged in April, July and August.

Reports are spread across the year, with 60% between May and September.

Blooms can appear, move with the wind and fade within hours or days, so the time of year is only a guide.

January: 0% of reports
February: 0% of reports
March: 0% of reports
April: 40% of reports
May: 0% of reports
June: 0% of reports
July: 40% of reports
August: 20% of reports
September: 0% of reports
October: 0% of reports
November: 0% of reports
December: 0% of reports
Share of reports by month. Darker bars are the peak months.

Recent East Fork Russian River algae reports

Recent reports came from 3 different locations around East Fork Russian River, including above Lake Mendocino, 5760 Kirk Drive and Access near Elledge Ranch Rd (114EF3696). A bloom in one cove or beach doesn't mean the whole lake is affected, and conditions can differ a short distance away.

DateLocationResult
9 April 2025 above Lake Mendocino Bloom reported
8 April 2025 5760 Kirk Drive Bloom reported
12 August 2024 Access near Elledge Ranch Rd (114EF3696) Algal mat alert sign
14 July 2023 River bank of 5760 Kirk drive, redwood valley, ca Bloom reported
14 July 2023 above Lake Mendocino Bloom reported

What the California results mean

California recommends one of three advisory levels when a bloom is checked, matched to the signs posted at the shore.

Caution
Toxins may be present. Stay away from scum and keep pets and livestock from drinking the water.
Warning
Toxins are at higher levels. No swimming, and keep children and pets away from the water.
Danger
High toxin levels. Stay out of the water and off the shore until further notice.
Bloom reported
A bloom was reported, often by a member of the public, without a formal advisory level.

Is East Fork Russian River safe for dogs?

Dogs are at the greatest risk from toxic algae. They swallow water while swimming, eat scum on the shore and lick algae off their fur afterwards, and a small amount can kill a dog within hours. With blooms recorded in 3 different years here, take particular care at East Fork Russian River in April, July and August.

  • Keep your dog on a lead near water that looks green, scummy, foamy or discoloured, and away from algae washed up on the shore.
  • If your dog gets in, rinse it straight away with clean water and don't let it lick its coat.
  • Call a vet immediately if your dog vomits, drools, has diarrhoea, staggers, shakes or seems weak after being near the water.

Read the full guide to toxic algae and dogs: symptoms, what to do in the first minutes and how vets treat it.

Health effects of toxic algae

Blue-green algae (cyanobacteria) can produce toxins that affect the liver, nervous system and skin. Swallowing water during a bloom can cause stomach pain, vomiting and diarrhoea. Skin contact can cause rashes, and breathing spray from the water can irritate the eyes, nose and throat. Children are at higher risk because they are smaller and more likely to swallow water.

How to spot a bloom

Toxic blooms can look like pea soup, spilled paint or green streaks on the surface, and they can also be blue, brown, white or red. Scum often collects along the shore downwind. If you can't see your feet in knee-deep water, or you aren't sure, stay out.

Don't drink untreated lake water, and don't boil it to make it safe: boiling doesn't destroy algal toxins. If you feel unwell after contact with the water, contact a doctor or Poison Control on 1-800-222-1222.

Nearby lakes with algae reports

All Mendocino County lakes with algae reports

Questions about East Fork Russian River

Is there algae in East Fork Russian River right now?

There are no bloom reports for East Fork Russian River in the last 30 days of California's data. The most recent was a bloom report on 9 April 2025 at above Lake Mendocino. California's data is checked every day, so for today's conditions check the California HABs Portal map and the signs at the shore.

When was the last algae bloom at East Fork Russian River?

The most recent entry in California's data is from 9 April 2025 at above Lake Mendocino: a bloom report.

Has East Fork Russian River had toxic algae before?

Yes. Blooms are recorded every year from 2023 to 2025, most often in April, July and August.

Can dogs swim in East Fork Russian River?

Keep dogs out of the water whenever a bloom is reported or the water looks green, scummy or discoloured. Dogs are the animals most often killed by algal toxins because they swallow water and lick their fur. If your dog swims in water that might have algae, rinse it with clean water and call a vet if it vomits, drools, staggers or seems weak.

Can you eat fish caught in East Fork Russian River during a bloom?

If you keep fish caught during a bloom, health agencies advise removing the guts and liver and rinsing the fillets in clean water before cooking, because toxins collect most in the organs. Some agencies advise not eating fish from an active bloom at all, so follow local guidance.

About this data

This page uses official records from the California State Water Resources Control Board, which updated daily. Reports are grouped by waterbody. The site was last rebuilt on 24 October 2026.

States only test some lakes, some of the time, so a lake without a recent report hasn't necessarily been checked. This page is independent, isn't affiliated with the State of California, and isn't health advice. View the source data.