Report
An observer has seen cyanobacteria beyond what is natural. It may be one shoreline sighting or a broader waterbody observation.
Stay alert and report changing conditions.Current water notice Report issued August 19, 2026
Cyanobacteria bloom confirmed at Robinson Pond
A cyanobacteria bloom has been observed at Robinson Pond, please see below for details. Do not swim in or near visible bloom material, and keep pets and livestock out of affected areas.
Water safety at Robinson Pond
Know before
you go in.
A cyanobacteria report is currently posted for Robinson Pond. Water conditions can change quickly—check the live status, read the posted sign, and keep people and pets away from visible blooms.
The water quality at Robinson Pond is tested through the NHDES Beach Inspection Program during the months of June, July and August.
Why testing matters
What triggers a beach advisory?
This program monitors public beaches for the presence of fecal bacteria. A beach advisory is issued when a water sample contains fecal bacteria levels that exceed the state standard, indicating unhealthy swimming conditions.
Advisory signs
Three signs. Three clear actions.
Depending on the results of the water quality last tested, one of the following three signs will be posted during the water testing season to inform visitors of the water condition.
GREEN
Monitored
SAMPLES MEET STATE BACTERIA STANDARDS
GREEN
Monitored
What it means
The most recent samples analyzed meet statutory bacteria standards for beaches.
What to do
The most recent samples analyzed meet statutory bacteria standards for beaches.
Signs are posted at the following areas within Robinson Pond:
- Main Gate
- Boat Launch
- On the Beach
Cyanobacteria harmful algal blooms
If the water looks wrong, stay out.
Harmful algal blooms are the rapid growth of algae or cyanobacteria in water that can harm people, animals or the environment.
Learn more about how to identify and report Harmful Algal Blooms by referring to the web links below.
Do not swim in or near visible bloom material. Keep pets and livestock out of affected areas, too.
Example: green surface streaks or scum
Understanding NHDES updates
Report, watch, or warning?
These labels describe different levels of observation and confirmation. A warning is precautionary and does not close the entire waterbody.
Watch
Cyanobacteria are above normal background levels at multiple locations but below 70,000 cells/mL, or photos clearly indicate a bloom.
Avoid visible bloom material.Warning
Microscopic evaluation exceeds 70,000 cells/mL and the bloom is widespread or present at multiple locations.
Potential health risks are present.Read the full definitions and guidance
Reports depict only what an observer sees in the water. The report may reflect a waterbody wide perspective if they boated around the waterbody and made observations, or it could be a single sighting from the shoreline. One sighting does not indicate that a watch or warning is necessary, but it does indicate that those on or around the waterbody should be aware that cyanobacteria have been observed beyond what is natural, and that they should be on the lookout for shifting bloom conditions and report them via the Bloom Report Form.
Watches are issued when samples are evaluated and cyanobacteria are in higher abundance than normal background levels at multiple locations, but that densities are below 70,000 cells/mL or when clear photographic evidence indicates a bloom is occurring.
Warnings are issued when samples are evaluated microscopically, and cell counts exceed 70,000 cells/mL and the bloom is widespread or extends to multiple locations on the waterbody. A warning does not close the waterbody to recreational use. The warning is intended as a precautionary measure to inform the public of the potential health risks associated with cyanobacteria blooms. Please see our updated FAQs for more information.
When cyanobacteria has been confirmed by the NHDES, the Red Cyanobacteria Advisory sign will be posted.
NHDES advises lake users to not swim in or near the vicinity of where bloom material is visible. Please also keep pets and livestock out of areas where bloom material is observed.
Please visit the Healthy Swimming Mapper for the most current information about bloom location, status, and severity.
If you would like to be added to the NHDES email distribution list, please sign up to be directly included on future communications from NHDES. If you prefer to no longer receive these sampling updates, simply respond, and indicate "unsubscribe".