Overview | Bacteria | Phosphorus | Other Contaminants

Pollution in the Mystic today

Cuyahoga River on Fire

Cuyahoga River on Fire

Deer Island Wastewater Treatment Plant

Deer Island Wastewater Treatment Plant

The good news is that, thanks to the Clean Water Act, pollution no longer looks like this. (As the most urbanized watershed in New England) the Mystic is cleaner, but our work is not yet done.

Photo credit: Neponset River Association

Photo credit: Neponset River Association

Stormwater pollution is now one of the leading source of pollution in our water today.

What is stormwater pollution?

“Stormwater” is a fancy word for heavy rain or snowmelt.

Flickr - Creative Commons

Flickr - Creative Commons

Stormwater runoff occurs when rain flows over land - driveways, lawn, and streets - into the nearest catch basins.

Photo Credit: US EPA

Photo Credit: US EPA

and then is discharged directly into our water bodies.


Stormwater pollution happens when the water picks up pollutants such as oil from a car, dog poop, excess fertilizer, herbicides, and pesticides on lawns, salt and de-icing materials, cigarette butts and other trash.  


These pollutants go down the nearest catch basin and end up in our lakes, rivers, and streams.


They are the reason many of our waterways are not swimmable or boatable. They negatively affect the plants growing in our waterways, as well as the wildlife living there.

So How Polluted is the Mystic?


Parts of the Mystic are cleaner than you might think (see green segments) while there is still work to be done!

MyRWA, with the help of a dedicated corps of volunteers,  has been collecting water quality data for 18 years now. Based on this data, this report card is put together on an annual basis by the EPA. Water quality grades are given to sections of the rivers and streams based on how often they comply with state swimming and boating standards.


Water samples are collected from fifteen sites across the watershed and are analyzed for bacteria (including e.coli), total suspended solids, nutrients (including phosphorus), conductivity, dissolved oxygen, water temperature, and water color/ odor.

Did you know that pollution in our water varies day to day?


Can you guess when the water is most polluted?


You guessed it! After it rains, when the stormwater carries pollutants into our waterways.

Curious about the water quality today, go here.

So what exactly is polluting our water?