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Water Conservation

Water Cycle

Underground Source

Distribution System



Long Island’s sole source of water has a very interesting past and present. To understand how Westbury residents enjoy such clean and purely delicious drinking water, one must understand the sole source of water - aquifers.

An aquifer is an underground geological formation composed of sand, gravel or rock and is capable of storing large quantities of groundwater. These natural storage tanks are tapped into by utilities located throughout the region including the Westbury Water District.

All of Long Island’s public water supply is stored in three aquifers, all of which possess different yet vital roles in the preservation of nature’s most precious resource.

Approximately 10 million years ago, the glacial sands and gravel that make up Long Island formed to generate one large unenclosed aquifer. Today, this aquifer is known as the Upper Glacial Layer. Since the water that resides in this layer consists of precipitation that fell between the last 10 to 50 years, it is not utilized as drinking water for the public.

The region’s most important source of drinking water is the Magothy Aquifer. Located just below the Upper Glacial Layer, this aquifer is the largest formation, reaching as deep as 200 to 1,000 feet below the earth’s surface. It is composed mainly of sand, gravel and silt and contains water that has trickled down from the Upper Glacial Layer.

Just underneath the Magothy Aquifer is the Raritan Clay Layer. This layer is quite thick, about 100 – 200 feet, and sits between the Magothy and Lloyd Aquifers.

The deepest and oldest aquifer is the Lloyd Aquifer. Mostly untapped, it is situated more than 200 feet below the earth’s surface and may contain water that is more than 5,000 years old. The Lloyd Aquifer provides tap water to a small amount of towns on Long Island, including Long Beach, Lido Beach and Point Lookout.

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