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There are many misunderstandings about how the Long Island groundwater system works and what are the best approaches to keeping it clean and plentiful. The following list is a summary of some of the most common misconceptions about the Long Island system.

Long Island Water: Myths and Facts

Myth: "City water" on Long Island comes from upstate reservoirs transported via the New York City water supply system.

Fact: No water is brought into Nassau and Suffolk Counties from New York City. Instead, rain falling on Long Island is the only source of public drinking water. Rainwater percolates into underground sand and gravel formations called aquifers. Wells pump water from the aquifers to provide nearly 3 million Long Islanders with their drinking water.

Myth: "Clustering" new development into closely spaced communities is all that is needed to protect future groundwater (drinking water) quality.

Fact: "Clustering" development means allowing higher density development in one area, while keeping the remaining parcel of land as open space. While this technique preserves open spaces, it does not, by itself, provide adequate protection of groundwater quality.

Myth: 1-acre zoning (allowing one house per acre) is adequate to maintain pure groundwater supplies.

Fact: Varying degrees of groundwater contamination from nitrates and chemicals have already been detected in some developed areas of Long Island which currently have 1-acre zoning or even larger lots. Changes in the use of harmful chemicals are also needed, along with using large lot sizes to reduce the overall loading of pollutants into the groundwater.

Myth: Water that enters the Central Pine Barrens does not recharge the Magothy aquifer, from which most Long Islanders get their drinking water.

Fact: The Central Pine Barrens in eastern Brookhaven are located in one of nine Special Groundwater Protection Areas (SGPAs) on Long Island. This means that, by definition, water entering the SGPA recharges (replenishes) the deeper aquifers, including the Magothy. Water in this deep aquifer migrates toward the north and south shores, providing many residents who live outside of the Pine Barrens in eastern Suffolk County with clean drinking water.

Myth: Water recharged into the Magothy Aquifer, underlying the Pine Barrens, will not be transported (piped) to the more populated areas of Long Island because it will never be feasible.

Fact: The five boroughs of New York City rely on drinking water that is transported for more than a hundred miles from upstate reservoirs. Trends of increased groundwater pollution and consumption in the deeper aquifers of western Long Island may create renewed consideration of this potential option as a viable water supply source in the future.

Myth: Long Islanders can safely rely on increased water treatment at the well head as the primary future solution to groundwater pollution.

Fact: Treatment of groundwater to remove pollution is very expensive and is not guaranteed to be free of human or mechanical failure. The ever-rising costs of treatment must be paid for by water customers, raising water bills with little additional benefit to the consumer. Wells that cannot be treated to meet increasingly strict safety standards must be permanently closed. Over the long term, effective prevention of groundwater pollution is a far less expensive and much healthier alternative.

Myth: Known groundwater contamination caused by spills, hazardous waste sites, landfills and residential and industrial discharges means the water coming out of the tap provided by public water suppliers is also polluted.

Fact: Not necessarily. Water companies must supply drinking water which meets State and Federal quality standards for a list of specific pollutants. Water supplies must be tested on a regular basis to ensure that the water is in compliance with existing standards. If the water does not meet standards, it cannot be legally distributed. As more of the total water in the groundwater system becomes polluted, there remains less pure water available. Consequently, expensive technology is required for treatment to meet drinking water quality standards.

Myth: There is an ample supply of groundwater under Long Island to meet our present and future water needs.

Fact: The amount of water in the aquifer system is limited. In addition to providing drinking water, an adequate supply of fresh water from groundwater is necessary for maintaining crucial ecosystems such as salt and fresh-water wetlands, creeks, streams, ponds, and bay salinity. Over-pumping, called groundwater mining, is depleting the aquifers in some areas, causing streams to disappear and salt water contamination of some coastal water supply wells.

Myth: "Environmentalists" are opposed to all future economic development on Long Island in order to protect the drinking water supply.

Fact: Groundwater protection advocates are saying that Long Island's environment and economy rely on one source of fresh water and that poorly planned development on the most important recharge areas has already caused serious groundwater pollution and expensive cleanup efforts in some areas. In the future, careful planning based on objective and comprehensive scientific evaluation must be used to determine where and what type of development is appropriate to prevent further groundwater pollution.

Updated by tbono 3/30/10