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  • Dylan D’Agate

Long Island’s Aquifer System: Our Sole Source of Water

Updated: Jun 23, 2021

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Have you ever thought about where the water we use on Long Island originates from?

A clear, cool, meandering stream from rural upstate? A majestic blue lake? Nope.

How about from directly under our feet! The water Long Islanders use to shower, water our lawns, cook, and, most important, drink, comes from an aquifer system directly underground and nowhere else. “Long Island’s sole-source aquifer system is the only source of water available to meet the needs of the Island’s population,” as stated by the United States Geological Survey. And in Nassau and Suffolk counties, that population numbers more than 2.8 million people.

What Is an Aquifer?

An aquifer is a large area of rocks or sediment saturated with groundwater -- think of a giant underground water-saturated sponge. How does the water get there? Most aquifers are naturally replenished, or “recharged,” by rainfall, snow, or other surface water that infiltrates the ground. We get water from the aquifer through wells that filter and pump the water out for use. The amount of water in an aquifer is determined by the balance between recharge and consumption. Over-consumption threatens the water levels in the aquifer, and pollutants from the air and surface can contaminate it.

What Is the State of Our Aquifer System?

Not good. In fact, according to an analysis in 2019 by the New York Public Interest Research Group, or NYPIRG, Long Island has the most contaminated drinking water in New York State. Sarah Meyland, J.D., who has worked as co-executive director of the NYS Legislative Commission on Water Resource Needs of Long Island and is director of the New York Institute of Technology’s Center for Water Resources Management, has said, “The story of Long Island’s drinking water — the bottom line is it’s getting worse.” Indeed, our wells are largely polluted with chemicals such as 1,4 dioxane and per- and polyfluoroalkyl substances (PFAs). A potential human carcinogen, 1,4 dioxane can be found in cosmetics, shampoos, and liquid soaps. PFAs can be found in such common household items as Teflon, paints, and cleaning products, and may lead to various adverse health outcomes including low infant birth weight and thyroid hormone disruption. If urgent changes are not made to policies regarding these chemicals, the problem will not be addressed until the damage is irreversible.

Pollution of our aquifer can be attributed to decades of human activities, including: Superfund sites. These areas are greatly polluted due to improper management of hazardous waste. Currently, Long Island has 256 superfund sites whose pollutants, if not removed quickly, seep down with rainwater to contaminate the aquifer. Nearly one-third of superfund sites on Long Island are radioactive. It is critical that these sites be monitored carefully to protect our water.

Excessive withdrawal of groundwater. When aquifer water is used to the extent that does not give the system time to replenish, the aquifer can be depleted. The average home on Long Island uses 400 gallons of water each day. That’s a lot of water! On top of this, since we are an island surrounded by saltwater, overdrawing water from our aquifer leads to lower freshwater pressure -- allowing higher-pressure saltwater to intrude.

Impervious surfaces. An excess of impervious surfaces can prevent aquifers from being

replenished – important to consider when towns and cities are being built. Water cannot permeate concrete or compacted gravel, for instance, and recharge an aquifer.

What Can We Do to Help Protect Our Aquifer System? Human activities can have a significant impact on the health of our aquifer system, including: (1) washing or flushing chemicals (e.g., paint, cleaners, rodent/insect poison, drugs) down a sink or toilet; (2) dumping chemicals on the ground that cannot be biologically degraded; (3) not maintaining a cesspool, septic system, or alternative wastewater system, resulting in excessive chemicals and elements (like nitrogen) getting into our aquifer system. Actions we can take to protect the system:

Conserve water at home. Take shorter showers and don’t leave the water running when brushing your teeth. Run the washing machine and dishwasher only after both are full. Browse “Ways to Conserve Water at Home / Sierra Club.”

Utilize your local S.T.O.P Program. STOP programs accept anything from paint, antifreeze, bleach, and pesticides to household and car batteries, propane tanks, and compact fluorescent lamps. Browse “Throwing Out Pollutants” (in your sanitation district) to inform yourself about such programs.

Don’t flush medications down the toilet. Doing so increases the chances they will end up in our drinking water. Rather, locate a local “Take Back Program” and find a free collection site near you.

Maintain your car. Precluding fluid or oil leaks can help prevent hazardous substances from entering our drinking water. Using a professional car wash, which disposes of harmful chemicals in an environmentally safe manner, will also help prevent hazardous chemicals from entering our storm drains and ultimately our water. Browse “A Professional Car Wash Has Environmental Benefits.”

Adjust lawn care. Most of the water used during the summer is on our lawns. Water your lawn only when needed and eliminate fertilizers and toxic pesticides that can wash into our groundwater.

Remove impermeable surfaces where possible. (1) replace solid surface patios with spaced stones so water can filter between the stones; (2) replace solid surface driveways/patios with permeable block or non-solid surface decking over open ground; (3) use only permeable ground covers for plant beds; (4) add dry wells for water that runs off solid surfaces like your house roof or driveway.

Write to local lawmakers. As a constituent, demand legislation that ensures reduction in excess use of impermeable surfaces.

When it comes to thinking about our aquifer system, it is important to remember these words from agronomist and Nobel Peace Prize recipient Dr. Norman Borlaug: “Clearly, we need to rethink our attitudes about water and move away from thinking of it as nearly [sic] a free good and a God-given right.”

For more information on our aquifers, click as well as


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