Is Rockland Lake safe? Toxic algae status
Rockland County, New York. Harmful algal bloom (blue-green algae) reports from the New York State Department of Environmental Conservation (DEC).
Data checked 24 October 2026. New York data is published as a yearly summary; the current season is shown on the NYHABS map.
14 of 14
years on the state's bloom list (2012–2025)
0
years with a confirmed high-toxin bloom (recorded 2012–2018)
2012
first year a bloom was listed
Year by year
Each year the lake appeared on the state bloom list, with its highest status.
Reports at Rockland Lake are most often logged in April, June and August.
Recent reports
| Date | Result |
|---|---|
| 9 April 2025 – 6 May 2025 | Confirmed bloom |
| 10 April 2024 – 31 October 2024 | Confirmed bloom |
| 9 April 2023 – 4 October 2023 | Confirmed bloom |
| 27 May 2022 – 27 October 2022 | Confirmed bloom |
| 3 November 2021 | Confirmed bloom |
| 9 April 2020 – 4 May 2020 | Confirmed bloom |
| 18 June 2019 – 14 July 2019 | Confirmed bloom |
| 8 March 2018 – 20 October 2018 | Suspicious bloom |
| 11 August 2017 – 20 October 2017 | Confirmed bloom |
| 2 June 2016 – 14 August 2016 | Suspicious bloom |
| 12 June 2015 – 7 August 2015 | Suspicious bloom |
| 25 June 2014 – 29 September 2014 | Confirmed bloom |
What the results mean
Reported to the state but not yet confirmed as blue-green algae.
State staff confirmed a blue-green algae bloom from photos or samples. Avoid contact with the water where the bloom is.
Toxin levels high enough to be a health concern. Recorded separately in the 2012–2018 data.
Dogs and toxic algae
Dogs face the greatest risk because they swallow water and lick algae off their fur. If a bloom has been reported, keep dogs out of the water and away from scum on the shore. If your dog swims in water that might have algae, rinse it with clean water straight away and call a vet if it seems unwell.
Common questions
Is Rockland Lake safe to swim in?
The most recent entry in New York's published data is from 9 April 2025: confirmed bloom. Blooms have been recorded at Rockland Lake in 14 different years, so treat green, scummy or discoloured water with caution. For current conditions, check the NYHABS map and posted signs.
When does Rockland Lake get algae blooms?
In the state's records, reports are most often logged in April, June and August. Blooms are most likely in warm, calm weather, but they can appear at other times of year.
Source: New York State Department of Environmental Conservation (DEC), official data. This page is independent and not affiliated with the State of New York.