Piedmont Natural Gas Co. Inc. filed a request with the North Carolina Utilities Commission for a rate decrease that would reduce the average residential customer's monthly bills by about $2.51, or 4%.

If approved, residential service customers are expected to save about 51 cents per dekatherm, while small general service customers are expected to save 27 cents and medium general service customers expected to save 24 cents, according to a March 19 news release.

Piedmont files a request to adjust its residential and commercial billing rates twice each year, on April 1 and Nov. 1, a semiannual adjustment separate from the occasional rate adjustments to account for pricing changes of Piedmont's natural gas purchases for its customers, the release said.

Piedmont Natural Gas is an energy services company whose principal business is the distribution of natural gas to residential, commercial, industrial and power generation customers in portions of North Carolina, South Carolina and Tennessee.