The explosion was reported just after 11 p.m. Saturday in the Richmond Hill neighborhood, WISH-TV, Indianapolis, reported.
Citizens Energy has shut off gas to all the homes in the area and investigated potential gas issues in the neighborhood.
Indianapolis Fire Department spokeswoman Bonnie Hensley said the department continued investigating Sunday.
Some of the 200 people who were evacuated from the area were allowed back into their homes Sunday morning, The Indianapolis Star reported.
Firefighters allowed people to return to homes with little or no structural damage.
One resident of the Richmond Hill neighborhood, Kurt McDonald, told WISH-TV he went outside and saw one house "just gone." He said the house next door was caved in and people were yelling.
"My son, nephew and I went in and got one daughter out [and] got another daughter out. She had a pretty big head wound," McDonald said. "The husband was trapped under a ton of stuff and all kinds of debris, and the wife was stuck in the recliner."
Resident Whitney Paflanzer said it was "like a war zone."
"And it was dark and dusty, and I thought it was a nightmare -- it was a nightmare," he said.