HARRISBURG - State environmental officials failed to adequately monitor Pennsylvania's drinking-water supply and were slow to inform the public about the results of investigations during the height of the natural-gas-drilling expansion, according to an audit released Tuesday.

The 146-page report, prepared by Auditor General Eugene DePasquale, was sweeping in its criticism of the Department of Environmental Protection's handling of gas-well inspections, and its failure to provide timely and thorough information to citizens between 2009 and 2012.

"The DEP was underfunded, understaffed, and inconsistent" in its regulation of Marcellus Shale well activity, DePasquale said at a news conference.

He said that the natural-gas industry's boom in Pennsylvania offered "significant benefits" to the state and nation, but that those benefits could not come "at the expense of the public's trust, health, and well-being."

DePasquale, a Democrat who in his 2012 campaign vowed to audit DEP's monitoring of gas drilling, stopped short of saying that any cases of weak enforcement under the Corbett administration or the administration of Gov. Corbett's predecessor, Ed Rendell, jeopardized public health.

The audit came the same day a newspaper reported previously unreleased state statistics showing that gas and oil extraction has damaged Pennsylvania water supplies 209 times since the end of 2007.

The DEP said Tuesday that it would post the information - obtained by the Pittsburgh Post-Gazette through a Right-to-Know Law request - on its website in an effort to increase transparency.

Among the DePasquale audit's key findings:

In many cases, DEP officials failed in their statutory obligation to issue administrative orders when they determined that a gas-well operator had harmed the water supply.

DEP communicated poorly with citizens.

DEP was unprepared to handle citizen complaints.

There was no assurance that shale wells were inspected in a timely fashion.

The Corbett administration disagreed with most of the findings, saying changes have been made to address many of the problems that the audit raised.

"To a great extent, the audit report reflects how the Oil and Gas Program formerly operated, not how the program currently functions," said E. Christopher Abruzzo, the DEP secretary. "Many of the recommendations in the audit report have already been implemented" or are under consideration by the administration.

In one critical area, the auditor general found that despite a legal mandate to issue corrective orders to restore or replace the water supply when it was found to have been harmed by gas drilling, in 15 cases reviewed, only one such order had been issued.

DePasquale said the department has instead negotiated settlements with drillers, which he felt undermined the department's authority.

Abruzzo took issue with those findings in particular, saying it was within the agency's discretion not to issue an order and pointed out that in the other cases cited, operators voluntarily complied.

He also noted the agency has issued $900,000 in fines against the operators in question.

The Marcellus Shale Coalition, a drilling-industry group, pointed out that DEP has doubled its inspection staff in recent years.

"While our industry is squarely focused on continuous improvement, it's clear that Pennsylvania's regulatory regime is effectively meeting its objectives of protecting our environment and making certain that shale's broad benefits are fully realized," said coalition spokesman Patrick Creighton.

John Norbeck, vice president of the environmental group PennFuture, said the audit underscored that more needed to be done to protect citizens' health and the ecosystem.

"This report could not be clearer," he said. "DEP needs additional funding, more cops on the beat, and a robust monitoring system."