The decision by New York City to drop its plan to reopen 23 wells in Queens that tap into the aquifers that are Long Island's only source of drinking water is a matter of so far, so good for Long Island. But it's not a happy ending -- not yet, anyway.

The city still wants to renew its well permits, which expire in 2017, to keep its options open. So our region's elected officials and water advocates need to stay vigilant to ensure the permit process is transparent and comprehensive, and answers all questions about the impact on Nassau County of any potential pumping from those shuttered wells.

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The city planned to draw 33 million gallons daily for one year beginning in 2020, when it shuts down part of its system to repair leaky upstate aqueducts. But the project's contractor recently estimated a shorter shutdown, negating the need for supplemental water. In emergencies, however, the city could need access to those wells, some of which were pumping as recently as eight years ago.

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So the city still needs to do its promised environmental review, and that must be evaluated by the state Department of Environmental Conservation. It must be comprehensive and include potential impacts on the water table, saltwater intrusion and toxic-plume migration in Nassau. As the city produces such data, so should Nassau and Suffolk to form a complete regional picture of our critical shared resource. If the city's review passes muster, the DEC should issue a permit allowing emergency access only. And it should allow access to the four wells that tap the pristine Lloyd aquifer only in the most dire circumstances.

The city's decision indeed was good news for Long Island. But we must take the next step together to get the outcome we all desire.