NiSource Inc. utility Columbia Gas of Maryland Inc. on May 22 requested an increase in its base rates to help replace aging infrastructure and complete other upgrades for pipeline safety.

Columbia Gas of Maryland filed with the Maryland Public Service Commission for an annual revenue increase of about $3.7 million, according to a May 22 release. If approved, a residential customer consuming 70 therms of gas per month would see an average total bill of $91.62, from $84.86, representing a 7.97% increase. Average total bills for a small commercial customer and an industrial customer would rise by 5.33% and 1.43%, respectively.

The utility has spent more than $146 million from 2007 to 2018 on improving its distribution system. Columbia Gas of Maryland spent about $101 million of that amount to replace over 84 miles of bare steel and cast iron pipe.

The new rates are expected to take effect near the end of the year, the utility said. Columbia Gas of Maryland serves about 33,000 customers in three counties in Maryland.