The company posted a public notice Friday, explaining it filed a request with the Pennsylvania Public Utility Commission for the change in natural gas distribution rates.
To support infrastructure improvements, Columbia Gas requested an overall rate increase of $77.3 million per year, according to company spokeswoman Rachel Ford.
Beginning in July-if the PUC approves the utility company's entire request-the average customer's monthly bill will increase from $67.17 to $82.92.
The rate change will help pay for the gas company's pipeline improvements, which has created more than 800 jobs since 2008, Ford said.
Since 2007, Columbia Gas has spent $400 million to replace more than 2.3 million feet of pipe.
Locally, the company has recently performed work on pipelines in Loganville, Red Lion, Shrewsbury and York City.
In 2013 and 2014, the company plans to spend $140 million each year on upgrades, she said.
The improvements create a "safe and reliable system" for gas delivery and also modernizes the company's infrastructure for the next 100 years, Ford said.
The PUC can take nine months to review the proposed rate change, and it may grant all, some or none of the request, according to Ford.
Last fall, the PUC approved a 3.2 percent increase filed by Columbia Gas, when the utility company requested an 18.91 percent increase.Information explaining how customers can get involved in the recent rate proposal will be included in their October bills, and a public notice was posted in newspapers, and on the Columbia Gas and PUC websites.
Customers who oppose the rate increase may send a letter, explaining their position, to the PUC at Pennsylvania Public Utility Commission, P.O. Box 3265, Harrisburg, PA 17105-3265. They may also call the PUC at 800-782-1110.
Though it would take months for approval of a base rate increase, Columbia Gas customers will see an immediate increase in their bills next month when the company issues its quarterly gas cost adjustment Monday.
During the fourth quarter of the year, natural gas prices will increase 51 cents per therm, which will yield an average bill of $73.30, Ford said.
In the same period a year ago, the average bill was $75.64, she said.
"Prices are remaining low and stable," Ford said.
State law prevents natural gas companies from making a profit on the sale of gas to customers. The quarterly adjustment reflects the most current gas prices, she said.
Columbia Gas customers who may struggle with their bills are asked to call the company at 800-440-6111.
"We are a leader in customer service and energy, and have energy-efficiency programs and budgets to help customers manage their monthly costs," Ford said.