Threats to Water Quality

Pesticide and Fertilizer Use

The use of pesticides and the tendency to over-fertilize on private lawns and by municipalities on public green spaces remain major threats to water quality. US Geological Survey testing shows 30 pesticides show up in their testing of the Norwalk River. A primary focus for NRWA is working to reduce pesticides levels in our environment. We are a lead organization in the advocacy group CT Pesticide Reform. Read more on these issues here:

PFAS Chemicals

PFAS, Per- and poly- fluoroalkyl substances are a class of roughly 15,000 manufactured chemicals collectively referred to as PFAS which are used in a variety of products and applications including non-stick cookware, upholstered furniture, clothing, food packaging, and firefighting foam. These substances are not found naturally in the environment.

PFAS don’t break down, which is why they are known as "forever chemicals." As a result, they accumulate in our bodies and the environment. They leach into groundwater and spread. They are found in fish, wildlife, and almost all human bodies. And they’re toxic. PFAS chemicals are linked to kidney and testicular cancers, liver disfunction, hormone disruption, thyroid disease, reproductive disorders, infertility, low birth weights and even resistance to vaccines!

non-stick cookware, upholstered furniture, clothing, food packaging, and firefighting foam

Background: The CT legislature failed to vote on a bill to restrict PFAS in 2019 and four days after the legislative session ended, 40,000 gallons of firefighting foam containing PFAS leaked out of a hangar at Bradley International Airport and flowed into the Farmington River. On July 9th, Governor Lamont formed a task force to make recommendations on how to manage PFAS contamination. In 2021, Connecticut banned the use of PFAS in firefighting foam and in 2023 we banned use in food packaging.

In 2024, the EPA set Federal Drinking Water Guidelines for PFAS. USA Today’s database searchable by your address shows public water supplies often contains PFAS in excess of these limits. There is little information about the safety of well water in Connecticut. Individuals can screen their well water for PFAS using the relatively affordable Cyclopure test kits.

State Action: In 2024, Connecticut passed one of the most comprehensive laws restricting PFAS in the country. The law includes a requirement that manufacturers label outdoor apparel for very wet conditions that intentionally contains PFAS as "Made with PFAS chemicals" and beginning in January 2028 it bans the sale or manufacture of most products containing intentionally added PFAS.

To learn about CT bills protecting the Norwalk River and how you can support them, check our advocacy page.

Hazardous Waste

Paint and Other Hazardous Waste

Leftover products containing corrosive, toxic, ignitable, or reactive ingredients such as paints, cleaners, oils, batteries, and pesticides, have potentially hazardous ingredients requiring special care when you dispose of them. Always avoid pouring them down the drain, on the ground, into storm sewers, or putting them out with the trash.

Household Hazardous Waste Collection Days by Town.

Since the start of the Connecticut paint stewardship law in July, 2013, it has been convenient to recycle paint in Connecticut. PaintCare, a non-profit 501(c) (3) organization, was organized by the American Coatings Association to implement the state-mandated program. Connecticut has set up 131 drop-off sites where the public can take unwanted, leftover paint for recycling.
Paintcare.org drop-off locations

Paint Recycling for Wilton, Weston, Ridgefield, Redding

Pet Waste

In 1991, the EPA classified dog waste as a contaminant, putting it into the same category as herbicides, insecticides, oil, grease and toxic chemicals. Animal fecal matter contains bacteria, parasites, and viruses, as well as organic matter and nutrients, notably nitrogen and phosphorous. It’s best to throw pet waste away in the trash.

Pharmaceuticals

Flushing unwanted pharmaceuticals down toilets or putting them into the trash can contribute to contamination of surface waters, ground waters and biosolids.

In the watershed, New Canaan, Ridgefield and Wilton have an anonymous lock-box located in the foyer of the Police Station which is available for disposing of expired pharmaceuticals. Residents can deposit their unwanted drugs in the box year-round. The lock-box is emptied routinely using secure and confidential procedures, and methods for proper disposition.

Pharmaceutical drop-off sites in CT

Stormwater Runoff

The primary source of pollution in the Norwalk River is stormwater runoff from highways, parking lots and even our own driveways and rooftops. Stormwater runoff is rain and melted snow that flows off these impervious surfaces and our lawns and golf courses directly into waterways without first percolating through the ground. The natural percolation process cleans debris, oils, gasoline, pesticides and other contaminants from stormwater.

The EPA, CT DEEP, local municipalities, and homeowners all play an important role in helping manage stormwater runoff. Some strategies homeowners and cities use include green roofs, permeable pavements, rain barrels, and rain gardens. Green roofs are flat roofs planted with gardens that catch and filter rainwater. Permeable pavement is just what it sounds like: sidewalks, parking lots and driveways made of pavement that allows water to seep through it instead of run off it.

Rain barrels: available at hardware stores, rain barrels catch rooftop water from gutter systems for use in watering lawns and gardens, washing cars and dogs, and filling swimming pools. More information about rain barrels here.

Rain gardens catch runoff from paved surfaces and gutter systems. They are shallow depressions planted with perennials (native plants are best) designed to catch water and allow it to percolate through the ground instead of running directly into storm drains, streams or rivers. More information on rain gardens and how to install them here. NRWA in association with the University of Connecticut’s NEMO program installed a model rain garden in the Norwalk River watershed at the Wilton Playshop on Lovers Lane in Wilton. Stop by and see it just off the back patio.

Damaged Riverbanks

The Norwalk River’s banks have undergone modification by people in many places, often to the detriment of the river’s water quality and to the plant and animal life that lives along the river. The area along the banks of the river is known as the riparian zone and it is vital to the health of the watershed ecosystem. A healthy riparian zone is one where native plants are allowed to flourish. The area should be protected from mowing or any kind of construction. Pristine streamside “riparian” zones are vital because they:

Filter debris and contaminants from stormwater runoff
create shade which lowers water temperature and helps provide a stable habitat for aquatic life
prevent erosion by stabilizing banks--the roots and branches of riverbank vegetation help hold soil in place and help reduce the velocity of flowing water
provide food and shelter in the form of leaves, fruits and woody debris to both aquatic life and wildlife living on riverbanks
provide habitat and travel corridors for wildlife
absorb floodwaters safeguarding property during periods of high water

This damaged riverbank is along the Norwalk River behind the Wilton Y.

Invasive Plants

In Connecticut, we have more than 100 types of plants that have been classified as invasive. While many of these were first introduced for their ornamental interest, they have ‘escaped’ our gardens into the broader environment, resulting in numerous negative impacts on the entire ecosystem. Invasive plants provide little or no food for native wildlife to eat. The leaves, flowers, seeds, and berries of native plants are crucial for native insects, butterflies, moths and other pollinators as well as birds and other animals.

Becoming familiar with the common invasives is the first step toward taking action to halt their growth and spread on your own property and beyond, into the wetlands, meadows and forests. Encouraging existing natives and/or replacing invasives by planting native species helps restore our neighborhoods to their natural beauty and healthy conditions.
Common Invasives and Beautiful Native Alternatives
Complete List of CT Invasive Plant Species.

Leakage from Septic Systems and Overflows from Sewage Plants

Leakage From Septic Systems and Septic Storage Tanks
One of the most serious problems in water-quality tests on the Norwalk River is the presence of bacteria, part of which may come from unmaintained or malfunctioning septic systems and underground storage tanks. Regular inspections and pump-outs of septic systems are vital for a clean Norwalk River. More information about septic-system maintenance here. Questions about local regulations and practices should be directed to local health departments.

Sewage Plant Outflows
Discharges from "point sources" such as wastewater treatment plants and industrial discharge pipes are not nearly as severe a problem as they were thirty or forty years ago. Despite the many improvements, though, some serious areas of concern remain. One is “combined sewage overflow” (CSO) outfalls—municipal drainage pipe systems that combine sewage and rainwater. During heavy rain events that exceed the capacity of the wastewater treatment plants, these systems overflow. Climate change is causing heavier storms and exacerbating the problem of CSO overflows. As of 2025, six wastewater treatment plants in Connecticut still have CSOs, including Norwalk. Norwalk is currently working to end sewage overflows into Norwalk Harbor. More information on Norwalk’s CSO.

Many monitoring sites along the Norwalk River tend to exceed the CT DEP Class B river criterion for E. coli bacteria.

Sewage treatment plants along the river use ultra violet (UV) lights to kill bacteria in treated sewage water before returning it to the river. The plants are only required by law to use their lights to kill bacteria in the warmer months, May through September, when the community uses the river recreationally. One plant, the Georgetown plant, has elected to keep its lights working all year, and we applaud this important effort to keep the watershed healthy. In addition, the Georgetown plant upgraded its filter system in 2014, which will also help protect the river. The Ridgefield sewage treatment plant uses its UV lights two months longer than required, from April through October. A smaller third plant along Route 7 only uses its lights from May through September.

Microplastics

More Information Coming Soon...