Warning REMOVED 07/09/2025

Great news! The cyanobacteria warning at your waterbody is being REMOVED, please see below for details.  

Waterbody	Swains Lake, Barrington
Status	WARNING REMOVED
Issued	6/19/25
Resampling Date	7/9/25
Notes	Multiple samples were collected around the waterbody and there were no cyanobacteria present. Please report through the Bloom Report Form if bloom conditions reappear.

Please visit the Healthy Swimming Mapper for the most current information about bloom location, status, and severity.

Cyanobacteria 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. Reports will be removed from the Healthy Swimming Mapper after one week if no further reports are received.

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.

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. It is suggested that local authorities post the 2025 cyanobacteria sign at public access points while a warning is in place to alert the public of current conditions.