By Kris Maher 

Since taking over from a Republican administration this year, Democratic Pennsylvania Gov. Tom Wolf repeatedly has said he supports the state's booming shale gas industry. But lately, the industry is questioning his commitment.

State regulators, who have begun reviewing dozens of environmental cases the previous administration handled, recently imposed an $8.9 million fine for a gas well they said is contaminating drinking water--the largest ever against a gas operator in state history.

The state is also proposing a raft of stricter drilling rules to prevent wastewater from contaminating drinking water sources. And industry officials are upset that the Wolf administration earlier this month slashed its estimate of state jobs supported by the shale-gas industry to 89,000 from the previous administration's estimate of more than 200,000.

"This administration's words continue to be alarmingly detached from its actions as it relates to policy and regulatory matters," said Dave Spigelmyer, president of the Pittsburgh-based Marcellus Shale Coalition.

Jeffrey Sheridan, a spokesman for Mr. Wolf, said the administration seeks a balance between promoting development and protecting the environment. Mr. Wolf took office in January after defeating former Gov. Tom Corbett.

Mr. Sheridan said the prior administration's industry jobs figures were inflated, including road-construction workers, truck drivers not employed in the industry, and even state regulators.

Mr. Spigelmyer said the change appeared motivated more by politics than economics. Job numbers are a key indicator of the shale boom's importance to the state economy and are cited in debates about how much to tax and regulate drilling.

Another sore point for the industry is the governor's appointment of cabinet members who previously worked for an environmental nonprofit organization called PennFuture, including John Quigley, head of the state Department of Environmental Protection. The group has pushed for tougher drilling rules.

Mr. Sheridan said all the appointees were confirmed by the Republican-controlled state Senate and none is biased against the gas drilling.

Hydraulic fracturing, or fracking, has exploded since 2008 into a main economic driver for Pennsylvania. The state's natural gas production, mostly from fracked wells that tap the Marcellus Shale, exceeded 4 trillion cubic feet last year, doubling the state's 2012 output and making Pennsylvania the nation's second-largest gas producer behind Texas. Fracking involves pumping millions of gallons of water and chemicals more than a mile underground to free gas deposits.

This year, state and local governments will receive $224 million from the fees companies are required to pay on fracked wells. Such fees have generated a total of $855 million in revenue since they were enacted in 2012.

Tensions have built as Mr. Wolf and the Republican-led legislature appear unlikely to agree on a state budget ahead of a June 30 deadline. The governor has said he will veto a budget Republicans passed over the weekend because it doesn't include his top priorities, such as a new 5% severance tax on shale drilling that he estimates will bring in $1 billion in annual revenue to fund schools. A budget stalemate could continue for several weeks before residents begin to notice cuts to services, said experts.

Republican House Speaker Mike Turzai said he opposes the severance tax and believes the governor's revenue estimate is too high. "The governor's proposal will amount to a de facto moratorium on the development of natural gas in the Commonwealth," he said.

As the issue is debated, it isn't clear whether a new 5% severance tax on gas production would replace the current per-well fee or come in addition to it.

Pennsylvania residents continue to back shale-gas development, recent surveys show, but they have also supported a tax on production to help bridge a deficit the governor's office estimated at over $2 billion. The state's Independent Fiscal Office puts the shortfall at $1.5 billion.

On June 16, regulators announced an $8.9 million fine against Range Resources Corp. of Fort Worth, Texas, for allegedly failing to prevent natural gas and other substances from contaminating drinking water in Lycoming County.

Since 2008, the state has assessed $20.2 million in fines against the industry, not counting the latest fine. The highest one assessed previously was a $4.5 million fine against EQT Corp. The company is challenging the fine and declined to comment.

Regulators said Range hasn't repaired a defective well casing. "I cannot speak for why the previous administration chose not to take action, but this administration will," said Mr. Quigley, the state's top environmentalregulator.

Range, which is appealing the fine, said its testing showed that natural gas in 21 nearby residential wells was different from gas in Range's well. Separate testing concluded the cement casing around the well was sound.

"We are equally confident that the environment and community are not at risk," Range said in a statement.

Corrections & Amplifications

The largest fine Pennsylvania assessed against a natural-gas producer before this month's $8.9 million fine was one for $4.5 million, which is being challenged. A previous version of this article cited a fine for $4.15 million without clarifying it as the largest such fine that has been paid. (June 29, 2015)

Write to Kris Maher at kris.maher@wsj.com