UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 5)*

DOMINION ENERGY MIDSTREAM PARTNERS, LP

(Name of Issuer)

Common Units Representing Limited Partner Interests

(Title of Class of Securities)

257454108

(CUSIP Number)

Carlos M. Brown

Dominion Energy, Inc.

120 Tredegar Street

Richmond, Virginia 23219

(804) 819-2000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

September 19, 2018

(Date of event which requires filing of this statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of § 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g) check the following box  ☐.

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.

Includes 26,675,082 Common Units held directly by Dominion Energy Midstream GP, LLC (“GP”). Cove Point owns all of the membership interests in GP and Dominion owns all of the common stock of Cove Point. Accordingly, Dominion may be deemed to indirectly beneficially own the Common Units directly held by GP.

Includes 6,656,839 Common Units held directly by QPC Holding Company (“QPC Holdco”). Dominion Energy Questar Corporation (“Dominion Questar”) owns all of the common stock of QPC Holdco and Dominion owns all of the common stock of Dominion Questar. Accordingly, Dominion may be deemed to indirectly beneficially own all of the Common Units directly held by QPC Holdco.

2

Includes 26,675,082 Common Units held directly by GP. Cove Point owns all of the membership interests in GP. Accordingly, Cove Point may be deemed to indirectly beneficially own the Common Units directly held by GP.

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Note: This Amendment No. 5 amends and supplements the Schedule 13D originally filed with the Securities and Exchange Commission on April 2, 2015 and subsequently amended on October 6, 2015, January 29, 2016, December 1, 2016 and July 9, 2018. Capitalized terms used in this Amendment No. 5 and not defined herein have the respective meanings ascribed to such terms in the Schedule 13D, as previously amended.

The information previously provided in response to this Item 2 is hereby amended and supplemented as follows:

The information required by subparagraphs (a), (b), (c) and (f) of this Item with respect to the directors and executive officers of the Reporting Persons is set forth on Schedule A attached hereto and is incorporated herein by reference.

During the last five years, none of the Reporting Persons nor, to the best of the Reporting Persons’ knowledge, any of the persons identified on Schedule A has been convicted in a criminal proceeding, excluding traffic violations or similar misdemeanors.

During the last five years, none of the Reporting Persons nor, to the best of the Reporting Persons’ knowledge, any of the persons identified on Schedule A was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 4 is hereby supplemented as follows:

On September 19, 2018, Thomas F. Farrell, II, Chairman, President and Chief Executive Officer of Dominion, delivered a non-binding offer (the “Offer Letter”) to the Issuer to acquire all of the outstanding Common Units of the Issuer not already owned by Dominion and its affiliates in exchange for common shares of Dominion, no par value (the “Dominion Common Shares”), at an exchange ratio of 0.2468 Dominion Common Shares for each Common Unit of the Issuer. The foregoing description of the Offer Letter does not purport to be complete and is qualified in its entirety by reference to the full text of the Offer Letter, which is filed as Exhibit 1 hereto and is incorporated by reference in its entirety into this Item 4.

There can be no assurance that any discussions that may occur between Dominion and the Issuer with respect to Dominion’s offer will result in the entry into a definitive agreement concerning a transaction or, if such a definitive agreement is reached, will result in the consummation of a transaction provided for in such definitive agreement. Discussions concerning a transaction may be terminated at any time and without prior notice. Entry into a definitive agreement concerning a transaction and the consummation of any such transaction is subject to a number of contingencies that are beyond the control of Dominion, including the satisfactory completion of due diligence, the approval of the board of directors of GP (the “Issuer Board”), the recommendation of the conflicts committee of the Issuer Board, approval by holders of a majority of the outstanding Common Units of the Issuer, and the satisfaction of any conditions to the consummation of a transaction set forth in any such definitive agreement.

Dominion does not intend to disclose developments with respect to the foregoing unless and until the Issuer Board and Dominion have approved a specific transaction, if any, and Dominion and the Issuer have then entered into a definitive agreement to effect such transaction, except as may be required by law. The foregoing is not intended to limit the matters previously disclosed in Item 4 of this Schedule 13D.

The information provided or incorporated by reference in Item 4 is hereby incorporated by reference herein.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: September 21, 2018

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SCHEDULE A

DIRECTORS AND EXECUTIVE OFFICERS OF

DOMINION ENERGY, INC.

The business address of each person listed below is c/o Dominion Energy, Inc., 120 Tredegar Street, Richmond, Virginia 23219. Each person is a United States citizen.

Directors:

Executive Officers:

DIRECTORS AND EXECUTIVE OFFICERS OF

DOMINION COVE POINT, INC.

The business address of each person listed below is c/o Dominion Cove Point, Inc., 120 Tredegar Street, Richmond, Virginia 23219. Each person is a United States citizen.

Directors:

Executive Officers:

DIRECTORS AND EXECUTIVE OFFICERS OF

DOMINION MLP HOLDING COMPANY, LLC

The business address of each person listed below is c/o Dominion MLP Holding Company, LLC, 120 Tredegar Street, Richmond, Virginia 23219. Each person is a United States citizen.

Executive Officers:

DIRECTORS AND EXECUTIVE OFFICERS OF

DOMINION ENERGY MIDSTREAM GP, LLC

The business address of each person listed below is c/o Dominion Energy Midstream GP, LLC, 120 Tredegar Street, Richmond, Virginia 23219. Each person is a United States citizen.

Directors:

Executive Officers:

DIRECTORS AND EXECUTIVE OFFICERS OF

DOMINION ENERGY QUESTAR CORPORATION

The business address of each person listed below is c/o Dominion Energy Questar Corporation, 333 South State Street, Salt Lake City, Utah 84111. Each person is a United States citizen.

Director:

Executive Officers:

DIRECTORS AND EXECUTIVE OFFICERS OF

QPC HOLDING COMPANY

The business address of each person listed below is c/o QPC Holding Company, 333 South State Street, Salt Lake City, Utah 84111. Each person is a United States citizen.

Director:

Executive Officers: