Shelter Island officials are asking town residents to cut back on their lawn watering and take other measures to restrict the use of water, saying some of the town's wells are showing early signs of problems.
"We had a bit of a drought here," Supervisor James Dougherty said Monday. "The recent rain helped a little. We're just trying to be prudent."
The town does not share a common aquifer with the rest of the East End, but relies on its own independent underground water supply.
The sole source of new water is rainfall, and there is no way to pump water from the North or South forks to Shelter Island.
Dougherty said the monthly testing of town wells has shown some wells have less water than normally available at this time of year.
So the town is asking residents to limit watering of lawns to nighttime.
For years, Shelter Island has required people with swimming pools to truck in water by ferry to fill them, and families along the shoreline who use private wells have battled against salt water intrusion for decades.
The groundwater table on Shelter Island is a bubble of fresh water floating on top of the salt water, and it can be only a few feet thick.
The town has adopted a ban on irrigation systems that use private wells, which will go into effect in 2013. The regulation was adopted in 2003, and homeowners with such systems were given 10 years to amortize the costs of their existing systems.
To deal with the ban, some Shelter Island homeowners are building cisterns to collect and hold rainwater, which can be used for irrigation. About a dozen people have taken out permits to build such cisterns.