Since 1992, volunteers have assessed and documented water quality in the Stony Brook-Millstone Watershed through our StreamWatch water quality monitoring program. StreamWatch measures the health of our water by testing water chemistry, measuring bacteria levels, and assessing the biological and physical health of our waterways. StreamWatch data helps The Watershed Institute better assess the impacts of pollution and land use on local streams and determine actions necessary to protect and improve water quality.

How Clean is our Water?

We use a number of parameters to determine water quality and stream health across our StreamWatch network including tests for phosphorous, nitrates, dissolved oxygen, bacteria, ph, water temperature, turbidity, and aquatic life. Click to read our Clean Water Report Card.

View the tabs to see how our watershed fares across the different parameters measured by StreamWatch from 2014-2016. Sites have been assessed on a scale of “Excellent”, “Good”, “Fair”, or “Poor” for each parameter individually, then used to determine if each subwatershed meets or fails the applicable water quality standards. Click here to check out our water quality assessment framework to see how we developed these scores.

StreamWatch Teams

Chemical Action Team (CATS)
StreamWatch gathers chemical data from over 40 monitoring sites across the watershed. StreamWatch CATS volunteers monitor one weekend per month and attend a mandatory Quality Assurance session in the Watershed Lab every year. Volunteers test six basic water quality parameters: water and air temperature, phosphates, nitrates, pH, turbidity, and dissolved oxygen. The results are analyzed and reported to the public through our quarterly subwatershed report cards, municipal report cards, and online. Data is also submitted to the EPA’s Water Quality Exchange.

CATS Field Data Sheet  |  CATS Digital PDF Form

Biological Action Team (BATS)

StreamWatch BATS monitor the populations of organisms called macroinvertebrates at 14 sites. Water quality ratings are based on the abundance of various species and their sensitivity to pollutants. If the stream is healthy, a diverse macroinvertebrate population can be found in a relatively small sample of water. A reduction in their numbers may indicate a high level of pollution. Sampling is conducted three times a year in March, July, and October and the organisms are identified to family level in the Watershed Lab. Beginning in 2017, one sample per year will be sent to a certified lab for identification to the genus level.

BATS Field Data Sheet  |  Lab Subsample Form  |  Macroinvertebrate Tally Sheet

Bacterial Action Team (BACT)
Through the StreamWatch bacterial action team, volunteers test for Escherichia coli (E. coli) levels in the water at 13 sites. E. coli is a type of bacteria that live in the intestinal tracts of animals and humans. The presence of this bacteria indicates that disease-causing bacteria, viruses, and parasites of a fecal origin may be contaminating the water. Swimming or wading in streams with highE. coli levels is considered to be a health risk. High E. coli levels can result from leaking septic or sewer systems, polluted runoff that has picked up animal (dog, goose, cow, etc.) waste en route to the stream, waterfowl in the stream, or wading cows. Monitoring is being used to keep an eye on several hot spots and to identify other bacteria problems quickly. Two five-week monitoring periods occur every summer. Volunteers can opt to participate in one or both sessions. All samples are analyzed in-house using the IDEXX/Colilert method.

BACT Field Data Sheet  |  IDEXX Bench Sheet


Becoming a StreamWatch volunteer is an easy and fun way to contribute to the health of your watershed. We rely on about 100 volunteers to assess water quality throughout our region. Volunteering requires an initial training session and at least a one-year commitment.

Become a Citizen Scientist


Interested about our methods and data quality? Read through our documents below.


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Water quality is ever-changing in response to changes in the landscape. Between 1930 and 2012, urban land increased from just 12% to more than 40% of the Millstone Watershed. How are our streams faring in response?


Get more information from our 2018 Citizen Science Forum presenters!


When last assessed in a subwatershed report in 2015, the water quality in Bear Brook was considered “good”. In this assessment, however, the overall water quality score for the brook is linked to the amount of pavement and other hardscape in the surrounding area…

citizen science symposium photo

Join us for a Citizen Scientist Symposium from 8:30 a.m.-3:30 p.m. on Sept. 14 at the Watershed Center.

Heathcote Brook

Heathcote Brook is one of the smallest subwatersheds in the Millstone basin. Its been monitored monthly by veteran StreamWatch volunteer Ted Chase since 2005!


Connie and Bill Bauder said they want future generations to acquire the connection with nature that they’ve enjoyed in their lifetimes and to become good stewards of our water and land.


There is a lot that we don’t know about the Royce Brook! Our water quality assessments are usually based on data collected from StreamWatch volunteers and NJDEP staff, but in this case…


Sonja Michaluk, 14, discovered her passion for streams and critters at a young age, and the Watershed has been a nurturing eddy where she’s developed her…


The Lower Millstone River is the final stop for waters in the Stony Brook-Millstone Watershed before they converge with the Raritan River and Raritan Bay. What happens here can be indicative of how the rest…

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With three monitoring sites along its muddy-bottom main stem and tributaries, the StreamWatch volunteer water quality monitoring program has tracked water quality in the Devils Brook subwatershed for 25 years.


With its bucolic beginnings amidst the sprawling agriculture of Millstone Township, Rocky Brook flows northwest through increasing urban development in Hightstown and commercial sections of East Windsor.

FERC Pipeline Photo

Most of the PennEast pipeline’s proposed route through NJ will interact with Fractured Bedrock Aquifers that feed the region’s private and community drinking wells.

Beden Brook looking downstream
Beden Brook Scorecard Aquatic Life ... Dissolved Oxygen ... Temperature ... Nitrate ... Phosphate ... E. coli ... pH ... Turbidity ... Impervious Cover ... Beden Brook runs over 10 ...
Creek Bed
Pike Run Scorecard Nitrate ... Phosphate ... Dissolved Oxygen ... pH ... Aquatic Life ... Bacteria ... Impervious Cover ... With its source in the Sourland Mountains, Pike Run and its ...