The proposed setback of a gas well from a water well is 500 feet. There is no science behind that, it’s just what the gas lobby agreed to. There have been many studies that address how gas wells mobilize methane into groundwater. Most of those studies measured gas levels either at or near the wellhead – not a distance from the wellhead. What should the setback be ? The short answer in New York is more than 500 feet. Because the only peer-reviewed study indicates that elevated levels of gas migration occur out to a kilometer from the well = 3,280 feet. There are no studies to indicate that the setback should be less than that – otherwise, the water well is likely to be contaminated. There have been white papers that seek to discredit the Duke study or attempt to explain away elevated levels of methane as being from other sources but there is no study that plausibly refutes what everyone in the industry knows: gas wells vent methane into groundwater. The only viable protection is an adequate setback of the gas well from water sources. In New York, that may be at the state line.