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Bathing Water Sampling








Beach or bathing water quality is measured by the presence of enterococcal organisms (a group of organisms that may indicate the presence of potentially harmful bacteria). The State of Connecticut has issued guidelines for bathing water quality – generally a concentration of enterococcal organisms exceeding 235 colonies per 100ml of fresh water is considered unsatisfactory for bathing.

The Chatham Health District wants to ensure that your day at the beach doesn’t result in illness related to poor water quality. At least once a week from mid-May to mid-September, one of our Sanitarians collects water samples from different bathing areas in the District. The water sample is sent to the state laboratory for analysis. When we receive the test results we compare them with the guidelines, if they are not satisfactory, we re-sample the water to double check the result. If the second test confirms the level, a bathing advisory is posted at that location. We will continue to monitor the site, and remove the posting as soon as the levels are safe.

Below is a list of the Bathing Water Sites within the Chatham Health District.

Beach Guidelines for Monitoring Bathing Water and Closing Protocols

Bathing Water Map Sampling Sites and Results

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Blue-green algae, also known as Cyanobacteria, occur naturally in lakes and ponds throughout Connecticut. These microscopic organisms are components of the aquatic food chain. In ordinary circumstances, Cyanobacteria cause no apparent harm, however warmer water temperatures and high nutrient concentrations may induce a rapid increase in their abundance. This response is commonly called a “bloom“ because algal biomass increases to the extent that normally clear water becomes markedly turbid. This tainted water takes on a green, blue-green or reddish-brown colored hue.

Sears Park Cyanobacteria Report 6/2/23 & Attachments

Sears Park Cyanobacteria Report 5/26/23 & Attachments


Blue - Green Algae Fact Sheet

Guidance Document

Blue - Green Algae Intervention Chart, What These Levels Mean

For More Information, Click on these Links:

Connecticut DEEP      Connecticut DPH

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