Water Quality Testing Data
The Town of Colchester performs water quality sampling annually each summer, with 2024 testing taking place Mondays and Wednesdays starting June 24th and ending August 28th.
Sampling is completed at the locations seen below.
Twelve water samples from 9 different sites are tested twice a week for the bacteria Escherichia coli (E. Coli). E. Coli is a very effective indicator for the possible presence of more harmful bacteria that can cause human health problems such as gastrointestinal dysfunction (gastroenteritis).
Contents
2024 Colchester Water Quality Test Results
2023 Colchester Water Quality Test Results
2022 Colchester Water Quality Test Results
2021 Colchester Water Quality Test Results
2020 Colchester Water Quality Test Results
2019 Colchester Water Quality Test Results
2018 Colchester Water Quality Test Results
2017 Colchester Water Quality Test Results
2016 Colchester Water Quality Test Results
2015 Colchester Water Quality Test Results
2014 Colchester Water Quality Test Results
2013 Colchester Water Quality Test Results
2012 Colchester Water Quality Test Results
2011 Colchester Water Quality Test Results
2010 Colchester Water Quality Test Results
2009 Colchester Water Quality Test Results
2008 Colchester Water Quality Test Results
2007 Colchester Water Quality Test Results
2006 Colchester Water Quality Test Results
2005 Colchester Water Quality Test Results
2004 Colchester Water Quality Test Results
Testing site abbreviations are as follows: 1DP - Horizon View/ Delta Park, 4PP - Porter's Point, R1 & R2 - Rosetti Park, 6SW - Spaulding's West Beach, 7MS - Moorings Stream, B1, B2, B3 - Bayside Beach, 8SH - Smith Creek, 9CT - Unnamed Stream "Camp T", 11CC - Crooked Creek
The Vermont State Health Department recommends not swimming in water where E. Coli levels are higher than 235 colony forming units (CFU) per 100 milliliters of water. When water samples come back with E. Coli levels higher than 235 CFU/100mL, those readings will appear in Bold.
The sites tested on a regular basis have been the same since 2007, which allows the Town to maintain consistency in our data collection. The sites tested are areas where there are likely to be large concentrations of people in the water, or areas where streams and tributaries enter into the Lake.
For Bayside Beach and Rossetti Natural Area, multiple samples are taken each testing day. If two or more of the samples have unsafe E. Coli levels, the affected beach will have signs erected warning of these high levels. The signs will remain until new tests come back with safe E. Coli counts.
Note: State parks perform their own E. Coli and Cyanobacteria water quality testing for Niquette Bay State Park. Results can be found at: https://vtstateparks.com/niquette.html .
AS A GENERAL RULE: Swimmers should always stay clear of streams, and where streams and storm drains flow into the lake. A distance of at least 100 feet from stream and drain outflows is advised.
Have Swimmers' Itch? Learn more about that here
The Lake Champlain Basin Program also performs water quality testing in Malletts Bay from April through October as part of the Lake Champlain Long Term Monitoring Project. Since 1992, the program has tested for phosphorus, nitrogen, chloride, and other nutrients, and scientists also watch for signs of cyanobacteria (blue-green algae).
If you have any questions or comments, please email DPW@colchestervt.gov or call the Stormwater Hotline @ 802-264-5628.
Have Swimmers' Itch? Learn more about that here
The Lake Champlain Basin Program also performs water quality testing in Malletts Bay from April through October as part of the Lake Champlain Long Term Monitoring Project. Since 1992, the program has tested for phosphorus, nitrogen, chloride, and other nutrients, and scientists also watch for signs of cyanobacteria (blue-green algae).
If you have any questions or comments, please email DPW@colchestervt.gov or call the Stormwater Hotline @ 802-264-5628.