October 3, 2019 Kirk R. Oliver Chief Financial Officer Equitrans Midstream Corp. 625 Liberty Avenue, Suite 2000 Pittsburgh, PA 15222 Re: Equitrans Midstream Corp. Form 10-K for fiscal year ended December 31, 2018 Filed February 14, 2019 File No. 001-38629 Dear Mr. Oliver: We have completed our review of your filing. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Sincerely, Division of Corporation Finance Office of Energy & Transportation