High levels of gas were detected during a routine inspection last Thursday morning, prompting the closure of roads near the intersection of Northern Avenue and Hardy Road.
Workers from Heath Consultants, a subcontractor for Southwest Gas, detected gas in two manholes at 7:55 a.m. Dec. 3. The workers then contacted Southwest Gas, according to Oro Valley Police Sgt. Matt Horetski.
The gas company called Golder Ranch Fire District and the Oro Valley Police Department, which decided to close the roads as a precaution.
Two nearby houses and two churches were evacuated. The intersection and surrounding roads were closed to all pedestrian and vehicle traffic.
Once the leak was found, at a transition line where one line connects to another, Southwest Gas closed off the main valves surrounding the leak. About six customers were temporarily without gas service.
Southwest Gas spokeswoman Libby Howell said inspections are ongoing throughout locations the company services. She said leaks, which are usually small, are not uncommon.
"The system worked the way it was suppose to work," Howell said. "We did the inspection and we found the problem before it could have been worse."
Roads were reopened at about 10:10 a.m. and the gas line was repaired that day.
Subsequently, a Tucson Water line, which was not marked according to Howell, was cut during the repair of the gas line. Because Tucson Water, Oro Valley Water and Metro Water service the area's water users, all three companies had to inspect the line to determine whose line was cut.
Tucson Water Conservation Program Manager Ilene Grossman said when the 6-inch main line was cut, approximately 275,000 gallons of water was lost. Grossman said the water main was repaired within 12 hours of the report.