HARRISBURG - Gov. Corbett's administration is recommending tougher laws to protect drinking water from pollution caused by booming natural-gas exploration in Pennsylvania.

Department of Environmental Protection Secretary Michael Krancer made the recommendations in a letter to Lt. Gov. Jim Cawley, who chairs the governor's Marcellus Shale Advisory Commission.

One recommendation would restrict well drilling within 1,000 feet of a public water supply. Currently, the law requires as little as 100 feet in many cases. Another would clarify the DEP's authority to revoke or refuse to issue a drilling permit and allow it to require comprehensive tracking of drilling wastewater.

Krancer also recommended expanding buffer requirements between gas wells and private drinking-water wells from 200 feet to 500 feet.

Pennsylvania is the center of activity in the Marcellus Shale formation, considered the nation's largest-known natural-gas reservoir. There have been more than 3,000 wells drilled in the past three years and thousands more planned as thick shale emerges as an affordable, plentiful and profitable source of natural gas.

When drilling companies began flocking to Pennsylvania several years ago to exploit the Marcellus Shale formation, they were largely working under laws from the 1980s that never envisioned deep-drilling activity that is combined with high-volume hydraulic fracturing, or fracking, and the recent innovation of horizontal drilling underground.

So far, the Legislature has done little to change that.