Sixteen years ago, Thiele authored a law under which anyone buying a house in the five East End towns must pay an extra 2 percent of the purchase price. The money is used to buy farmland and other open space to keep the space undeveloped.

Thiele is proposing using 10 percent of that money to protect the area's water.

The real estate tax is set to expire in 2030. Thiele's proposal would extend it another 20 years. He says that would bring in another $1.5 billion for land and water preservation.