SCRANTON - Erik Roos waited more than six years to tell a jury his story about shale-gas drilling and water contamination in rural Dimock Township. When he finally got a chance to testify this week, he was done in about a half-hour.

Roos was one of 44 Dimock residents who sued Cabot Oil & Gas Co. in federal court in 2009, alleging that the company's Marcellus Shale drilling had polluted their water wells. Roos and most of the plaintiffs settled in 2012, to his enduring dissatisfaction. But two families held out, and their three-week trial began Feb. 22 in U.S. District Court.

He was called to testify Tuesday as a witness for the families, but only about the stray methane in his water well and why he declined Cabot's offer to install a water-treatment system. When his testimony wandered into alleged health problems, hydraulic fracturing, or lingering animosity among neighbors over natural gas, Roos was cut off by U.S. Magistrate Judge Martin C. Carlson.

It was put to him that tests suggested the source of methane in his water might have been his livestock, not Cabot's gas well about 800 feet away. "I'm sure it's a combination of both," said Roos, 68.

Afterward, Roos shook his head in frustration. "This judge," he said outside the courtroom. "You can't get any stuff in."

For all the histrionics Dimock has generated since 2008 - two documentary films, investigations by federal and state environmental agencies, protests led by famous musicians and Hollywood actors - the final chapter has come to this: a sparsely attended trial narrowly focused on whether Cabot was a nuisance to two families.

Unable to establish that chemicals from hydraulic fracturing got into their water, or that the drilling caused illness, the plaintiffs find that their testimony is confined to narrow legal questions. As Carlson reminded the jury, the trial is about the property claims of two families, and no others. This is not a trial about fracking.

Scott Ely and Monica Marta-Ely and Ray and Victoria Hubert, along with the couples' children, are seeking compensatory and punitive damages. Cabot denies it caused the methane that got into their water wells, calling it non-toxic and treatable.

"I think we're going to prove something, and today is the start," Scott Ely told reporters as the trial commenced. The families say they have been unable to drink their water for more than seven years.

About 20 protesters demonstrated outside the courthouse on the trial's opening day, but attendance has dwindled as the testimony moved into technical issues about the construction of two gas wells near the Ely and Hubert residences. During some stretches of testimony, even the plaintiffs were not in the courtroom.

Cabot is represented by four partners from international law firm Norton Rose Fulbright, who are supported by a technical and clerical team. The litigators alternate examinations of the witnesses.

The families are represented by Leslie L. Lewis, a New York City sole practitioner who initiated the lawsuit while she was an associate with one law firm and took the case with her when she moved to a second. She later withdrew as counsel. After most plaintiffs settled in 2012, she returned to represent the Ely and Hubert families.

This week, Lewis appeared to struggle with industry terminology, confusing gas wells with water wells, casing with cement. At one point, she referred to the oil-and-gas services company Schlumberger as "Schlumberjack."

"What reason do you have for denying the truth?" she asked a Cabot employee, provoking a rebuke from the judge. She then wondered why the witness had such difficultly remembering events from Dimock. "Is that because it's convenient for your employer?"

"I'm going to direct you not to do that again," the judge barked. "That went over the line, Miss Lewis."

The plaintiffs' star expert witness, Anthony R. Ingraffea, a Cornell University civil-engineering professor, spent more than a day on the stand interpreting records of Cabot's two wells drilled about 700 feet from the Ely and Hubert homes. Those wells are at issue because drillers were then presumed liable for impairing water quality within 1,000 feet of their wells. (Pennsylvania later expanded the distance to 2,500 feet.)

Ingraffea suggested that faulty cementing of successively smaller-diameter steel casings inside the well failed to prevent natural gas from traveling up a void between the well bore and the surrounding rock to contaminate underground drinking-water supplies. The gas came from shallow rock layers, not the deep Marcellus, he said.

Ingraffea said he was not an anti-fracking activist, but "an advocate for science." He also said that to "maintain objectivity and personal integrity," he directed that his fee be paid to a nonprofit charity of his choice. "I want to be seen as completely without conflict."

Under cross-examination by attorney Stephen C. Dillard, Ingraffea admitted the fees went to PSE Healthy Energy, a nonprofit the professor co-founded that is active challenging fossil-fuel development. Ingraffea said he is not compensated by the organization.

The defense also produced photos of Ingraffea at anti-fracking events, including one at which the professor appeared on an Artists Against Fracking stage with entertainers Mark Ruffalo, Yoko Ono, and Sean Lennon.

Ingraffea said he worked with the organization as a "scientific adviser," not as an activist.

Cabot's lawyers also portrayed him as having little practical experience in the oil and gas industry. But they did note his previous research on rock-fracture mechanics for Schlumberger, whose work in the industry Ingraffea praised as among the best in the business.

Dillard, the Cabot lawyer, noted that Schlumberger had done most of the cement work on the two gas wells that Ingraffea found deficient. Cabot plugged and abandoned the wells in 2010.

"Sometimes bad things happen to good people," Ingraffea said.

After the plaintiffs rested their case on Thursday, Cabot moved to dismiss the trial without sending it to a jury. If the trial continues, it is expected to conclude next week.

215-854-2947 @maykuth