East Branch Hackensack River algae bloom history
New York's Department of Environmental Conservation listed East Branch Hackensack River as having a harmful algal bloom every year from 2013 to 2014.
- 2013 Suspicious, 11 reports
- 2014 Suspicious, 1 report
When do algae blooms happen at East Branch Hackensack River?
At East Branch Hackensack River, reports are most often logged in June and August.
About 100% of reports fall between May and September, when warm, calm, sunny weather lets blue-green algae multiply.
Blooms can appear, move with the wind and fade within hours or days, so the time of year is only a guide.
Recent East Branch Hackensack River algae reports
New York publishes one entry per lake for each season it appears on the bloom list, showing when it was first and last listed and its highest status.
| Date | Result |
|---|---|
| 25 June 2014 to 20 October 2014 | Suspicious bloom |
| 8 August 2013 to 2 October 2013 | Suspicious bloom |
| 1 August 2013 to 2 October 2013 | Suspicious bloom |
What the New York results mean
New York sorts each bloom by how far it has been checked.
- Suspicious bloom
- Reported to the state but not yet confirmed as blue-green algae.
- Confirmed bloom
- State staff confirmed blue-green algae from photos or a sample. Avoid contact where the bloom is.
- High toxins
- Toxin levels high enough to be a health concern. Recorded separately from 2012 to 2018.
Is East Branch Hackensack 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.
- 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.
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
- Deforest Lake1 km away, 2 reports, last in 2023
- Congers Lake3 km away, 3 reports, last in 2023
- Rockland Lake4 km away, 15 reports, last in 2025
- Lake Lucille8 km away, 6 reports, last in 2023
- Halsey Pond13 km away, 2 reports, last in 2025
Questions about East Branch Hackensack River
Is there algae in East Branch Hackensack River right now?
East Branch Hackensack River was not on New York's bloom list in 2025. It was last listed in 2014, with suspicious bloom status. New York publishes its data once a year, so for today's conditions check the NYHABS map and the signs at the shore.
When was the last algae bloom at East Branch Hackensack River?
The most recent entry in New York's data is from 25 June 2014: a suspicious bloom.
Has East Branch Hackensack River had toxic algae before?
Yes. Blooms are recorded every year from 2013 to 2014, most often in June and August.
Can dogs swim in East Branch Hackensack 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 Branch Hackensack 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 New York State Department of Environmental Conservation (DEC), which published as a yearly summary; the current season is shown on the NYHABS map. 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 New York, and isn't health advice. View the source data.