WASHINGTON — Washington Gas parent company WGL Holdings is one step closer to being acquired by a Canadian utility, with approval from the Maryland Public Service Commission, which has laid out requirements for the utilities to get its approval.

Calgary, Alberta-based AltaGas, agreed to acquire WGL in January 2017 for $4.5 billion.

The two companies have until April 16 to review the Maryland PSC’s approval conditions, which include a one-time $50 credit for Maryland residential heating customers, $22.8 million to Montgomery and Prince George’s counties for customer, education, workforce development and energy efficiency programs, and $100 million to expand natural gas infrastructure in the state of Maryland.

It will also require the companies to develop new renewable energy resources and AltaGas is required to move its U.S. power business headquarters to Prince George’s County.

The merger still needs approval from the D.C. Public Service Commission. That decision is expected in mid-2018.

It has already been approved by shareholders of both companies, the Federal Energy Regulatory Commission, the Federal Trade Commission and the Virginia State Corporation Commission.

Once approved, WGL Holdings would continue to operate as a stand-alone utility headquartered in D.C.

WGL Holdings has about 1,500 employees in Washington and about 1.1 million customers in the D.C. region.

AltaGas runs power plants across North America and owns two other U.S. gas utilities — Michigan gas utility Semco Energy Gas Co., and Alaska gas utility Enstar Natural Gas Co.