Is It Clean?



Red Not Clean for Boating or Swimming
Yellow Clean for Boating
Blue Clean for Boating and Swimming
White Results Available - See Link
Grey Historical Data

 IMPORTANT 8/22/19: We have been notified by MassDEP that the Town of South Hadley, MA had a Sanitary Sewage Overflow, or discharge of untreated wastewater, into the Connecticut River Thursday, August 22nd during a valve replacement at a sewer pumping station. The discharge happened just downstream of the Holyoke Dam between 11:30AM and 3:53PM. The town’s conservative estimate of discharge is 290,000 gallons over the four+ hours. The flow of the CT River at a USGS gage near this location during this time period was between 3,000 and 4,000 cubic feet per second (cfs), which is 80 million gallons per hour or more, so this discharge would be diluted and moved downstream. MassDEP and EPA are aware of the discharge, and downstream boards of health have been notified.

CRC’s volunteer monitors collected samples this morning prior to the discharge, so testing results will not reflect the river conditions after the discharge occurred. Please be aware that results posted on 8-22-19 downstream of the Holyoke Dam do not reflect post discharge levels of bacteria.

BLUE Clean for swimming and boating <235 cfu/100 ml
YELLOW Clean for boating only 235 - 575 cfu/100 ml
RED Not clean for swimming or boating >575 cfu/100 ml
WHITE Results available – See Link   
GREY Historical Data   

The Connecticut River and its tributaries are much cleaner today than they were decades ago. The Clean Water Act, smart investments, and the hard work of many people have made this possible. But, there are times – particularly after rain – when bacteria in our rivers still might make you sick. This tool will help you understand trends in water cleanliness at sites throughout the Connecticut River watershed, including many popular river recreation sites.


This map shows locations tested for Escherichia coli (E. coli) bacteria. Click on the blue, yellow, or red icons to learn more about bacteria levels at that site. Or use the drop-down boxes to search by site name, city, state, water body, or monitoring organization.

NOTE: This information is a snapshot of river conditions at the moment the sample was taken. Open each sample location’s page for more detail and historical data showing trends in water cleanliness. Be sure to take the most recent sample date into account as well as patterns over time, recent weather, and flow conditions when deciding whether to swim or boat.

Bacteria levels are typically elevated during and shortly after wet weather. Good precautions to take include:

  • Avoid swimming right after a heavy rain
  • Avoid contact with the river downstream of a sewage outfall
  • Cover open cuts, use ear and nose plugs
  • Wash hands before eating or drinking

The different colored icons and bacteria ranges represent risk thresholds, which are based on the statistical chances of getting sick if you come in contact with water in these bacteria ranges. We test for E. coli, a bacterium that is found in the guts of all warm-blooded animals, including humans. Most E. coli will not cause illness. We test for E. coli because it is often an indicator for the presence of other, more difficult to test for pathogens that may cause waterborne illnesses to those swimming, wading, or boating. View more detailed information about bacteria in our rivers or at beaches. 

We wish you a fun and safe season enjoying your rivers!

Interested in historical data? Make a request via email.

Funding for the Spanish language version of this page – ¿Está Limpio – was provided by the Franklin Fund and Nan and Matilda Heydt Funds of the Community Foundation of Western Massachusetts.