Homes in Wellingborough had to be evacuated on Saturday night after vandals damaged gas supplies.
Gas leaks were caused by surges after a distribution pump and pipes were deliberately damaged.
People were asked to leave 20 homes in the Valley Road area until Transco engineers said it was safe to return.
Insp George Cooper, from Northamptonshire Police, said the damage had caused a potentially dangerous situation.
"The implications were very serious when it's damage to a pipe which may well then have affected an underground pipe - which caused the gas to escape," he said.
A spokesman for Transco said the system had behaved as it should and there had been no immediate danger.