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Protecting Our Aquifer

Every drop of water in Suffolk County originates from beneath our feet. Protecting this vital resource through science, conservation, and preservation is our primary mission.

The Long Island Aquifer System

Drinking water on Long Island comes entirely from underground geological formations known as aquifers. These deep, saturated layers of sand and gravel act as a massive natural filter for the rain and snow that recharges them over hundreds, or even thousands, of years.

Upper Glacial Aquifer 43% of Active Wells

The shallowest layer containing the youngest water. Because it is closest to the surface, it is the most vulnerable to human contamination.

Magothy Aquifer 56% of Active Wells

The largest and most crucial formation for Long Island's drinking water. It holds water that is often hundreds of years old.

Lloyd Aquifer 1% of Active Wells

The deepest layer, resting on solid bedrock. It contains water held for over 5,000 years and is largely kept untapped by law to preserve it for coastal communities.

The Central Pine Barrens

The Suffolk County Water Authority actively supports land preservation as the ultimate form of source water protection. By protecting the land above, we avoid the future costs associated with monitoring and treatment.

We helped draft the Pine Barrens Protection Act, which preserves over 100,000 acres of pristine forest in central Suffolk County. The deep root systems of this protected space act as a massive, natural filtration sponge, ensuring the water recharging the aquifer below remains pure and abundant.

Learn more about the Pine Barrens Commission →

Modern Threats & How You Can Help

Surface Contamination

Because Long Island's sandy soil drains rapidly, chemicals put on the ground inevitably make their way into the Upper Glacial aquifer.

Take Action at Home:

Do not flush unused pharmaceuticals down the toilet. Use a designated Suffolk County medication drop box.
Avoid over-applying nitrogen-rich lawn fertilizers and pesticides.
Never dump motor oil, paint, or household hazardous waste into storm drains or on the ground.

Water Waste

Excessive water use depletes the aquifer faster than rainfall can recharge it, putting strain on local infrastructure and the environment.

Take Action at Home:

Adhere to SCWA's Odd/Even Lawn Watering schedule during the summer months.
Upgrade to a Smart Irrigation Controller (and apply for an SCWA account credit).
Routinely check for and fix household plumbing leaks and running toilets.

Saltwater Intrusion

Our freshwater aquifer sits like a "lens" surrounded by ocean saltwater. Over-pumping wells near the coast reduces freshwater pressure, pulling saltwater in.

Take Action at Home:

SCWA manages well rotation to distribute draw, but your conservation directly helps maintain the freshwater lens pressure.
Avoid running high-volume irrigation systems during peak neighborhood demand hours (early morning).