Somebody ratted Patrick Kelly out to the Philadelphia Gas Works, which dispatched a revenue-protection team to his Fox Chase home in 2015 to inspect his incoming gas line.

Investigators for PGW discovered a flexible metal hose attached to the house's service line, bypassing the utility's meter. The illegal line supplied free fuel to two furnaces, a hot water heater, a gas range, a gas dryer, and a swimming pool heater.

PGW cut off service to the house in the 700 block of Strahle Street and said the customer owed $21,000 for unauthorized gas used from 2003 through 2015, on top of the $7,800 Kelly was actually billed.

A heating and air-conditioning contractor, Kelly denied knowledge of the bypass and complained to the Pennsylvania Public Utility Commission.

On Thursday, an unsympathetic PUC voted, 3-1, to uphold a recommended decision that Kelly pay $18,378.72, an amount adjusted down to reflect a change in the estimated date when one of his gas appliances went into service.

Commissioner David W. Sweet cast the only dissenting vote, but not in Kelly's favor. Sweet argued that a deadline had passed to legally adjust the amount owed, and that Kelly should actually pay $21,000, plus reconnection fees.

"I see no reason for this commission to reach beyond our lawful authority in order to give partial relief to this particular complainant," he said.

The panel also rejected Kelly's request that PGW give him a payment agreement.

Each year, the PUC deals with thousands of utility customers' complaints, a fraction of which proceed through a formal hearing and go to the full commission. But few customers caught with an illegal bypass go public and seek relief from the agency.

"Theft of natural gas is a dangerous practice that puts people's lives at risk and forces honest ratepayers to cover the fuel cost," PGW spokesman Barry O'Sullivan said Friday. The city-owned utility was satisfied with the PUC's decision, he added.

Kelly did not respond to email and phone messages left with his answering service and his lawyer.

He converted his residence to propane and electric appliances after PGW shut off his service in October 2015 and did not dispute that PGW found an illegal tap on his property. But in testimony before a PUC administrative law judge, Kelly denied knowing anything about the bypass.

Neither PGW nor the PUC attempted to determine who installed the bypass, since Kelly was responsible for it because it was on his property. "People can draw their own conclusions," O'Sullivan said.

Andrew M. Calvelli, the administrative law judge, dryly noted in his recommended decision that Kelly has owned a heating and air-conditioning business since 1993. "Mr. Kelly installs a lot of air conditioners, heaters, walk-in boxes and refrigeration equipment as part of his business," the judge wrote.

According to public records, Kelly bought the house in 2003 for $225,000. It had a gas dryer, a gas water heater, and a gas range.

Kelly installed a 100,000 BTU gas heater in 2003 and added a 50,000 BTU heater in 2009. In April 2014, he had a pool installed at the address, along with a 300,000 BTU gas heater to heat the pool.

The size and installation dates of the appliances were pertinent when PGW went about computing how much unbilled gas was consumed. For instance, PGW said it estimated that the pool was open from May to September, which is typical for a residential outdoor pool in Philadelphia, and was heated to 78 to 80 degrees.

Kelly disputed PGW's methodology, testifying that he let the weather heat his pool, and that he did not maintain the temperature between 78 and 80 degrees as suggested.

"I do not find such testimony to be credible," Calvelli wrote in his recommended decision.

The administrative law judge did adjust down the estimated total, which Commissioner John F. Coleman Jr. said he found acceptable, despite Sweet's dissent.

"While I share the displeasure with my colleagues of  the conduct of this customer, I believe the evidentiary record requires that we affirm the ALJ's decision," Coleman said.