Exhibit 23.1

CONSENT OF INDEPENDENT AUDITORS

We consent to the incorporation by reference in Registration Statement No. 333-251074 on Form S-3 and Registration Statement Nos. 333-215145-01, 333-155581-01, 333-200835-01, 333-168731-01, 333-215150-01, 333-185354-01, and 333-222048 on Form S-8 of Southwest Gas Holdings, Inc. of our report dated April 14, 2021, relating to the financial statements of Dominion Energy Questar Pipeline, LLC appearing in this Current Report on Form 8-K/A dated March 14, 2022.

Exhibit 99.1

Dominion Energy Questar Pipeline, LLC

Consolidated Financial Statements

(Unaudited)

Period Ended September 30, 2021

Dominion Energy Questar Pipeline, LLC

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GLOSSARY OF TERMS

The following abbreviations or acronyms used in this document are defined below:

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CONSOLIDATED FINANCIAL STATEMENTS

DOMINION ENERGY QUESTAR PIPELINE, LLC

CONSOLIDATED STATEMENTS OF INCOME

(Unaudited)

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

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DOMINION ENERGY QUESTAR PIPELINE, LLC

CONSOLIDATED BALANCE SHEETS

(Unaudited)

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

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DOMINION ENERGY QUESTAR PIPELINE, LLC

CONSOLIDATED BALANCE SHEETS (CONTINUED)

(Unaudited)

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

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DOMINION ENERGY QUESTAR PIPELINE, LLC

CONSOLIDATED STATEMENTS OF EQUITY

(Unaudited)

QUARTER-TO-DATE

YEAR-TO-DATE

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

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DOMINION ENERGY QUESTAR PIPELINE, LLC

CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

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NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

Note 1. Description of Business and Basis of Presentation

Dominion Energy Questar Pipeline is a limited liability company owned by Dominion Energy Questar (effective November 2020) which is a wholly-owned subsidiary of Dominion Energy. Dominion Energy Questar Pipeline owns and operates interstate natural gas pipeline and storage facilities in the western U.S., including a 50% noncontrolling partnership interest in White River Hub. Dominion Energy Questar Pipeline’s operations are primarily regulated by FERC.

In July 2020, Dominion Energy entered into an agreement to sell substantially all of its gas transmission and storage operations, including Dominion Energy Questar Pipeline, to BHE. In October 2020, pursuant to a provision in the agreement with BHE, Dominion Energy elected to exclude Dominion Energy Questar Pipeline from the transaction as approval under the Hart-Scott-Rodino Act had not been obtained by mid-September 2020. Concurrently in October 2020, Dominion Energy entered into an agreement with BHE for the sale of Dominion Energy Questar Pipeline contingent on clearance or approval under the Hart-Scott-Rodino Act and other customary closing and regulatory conditions. In July 2021, Dominion Energy and BHE mutually agreed to terminate the sale of Dominion Energy Questar Pipeline as a result of ongoing uncertainty associated with receiving approval under the Hart-Scott-Rodino Act. Dominion Energy simultaneously announced its intention to pursue the divestiture of Dominion Energy Questar Pipeline to an alternative buyer. In October 2021, Dominion Energy entered into an agreement with Southwest Gas Holdings, Inc. for the sale of Dominion Energy Questar Pipeline contingent on clearance or approval under the Hart-Scott-Rodino Act and other customary closing and regulatory conditions. In November 2021, the waiting period under the Hart-Scott-Rodino Act expired. The sale is expected to close by the end of 2021.

Note 2. Significant Accounting Policies

Interim Financial Information and Estimates

Dominion Energy Questar Pipeline’s accompanying unaudited Consolidated Financial Statements contain certain condensed financial information and exclude certain footnote disclosures normally included in annual audited consolidated financial statements prepared in accordance with GAAP. These unaudited Consolidated Financial Statements should be read in conjunction with Dominion Energy Questar Pipeline’s Consolidated Financial Statements and Notes for the year ended December 31, 2020.

In the opinion of management, the accompanying unaudited Consolidated Financial Statements contain all adjustments necessary to present fairly Dominion Energy Questar Pipeline’s financial position at September 30, 2021, its results of operations and changes in equity for the three and nine months ended September 30, 2021 and 2020 and its cash flows for the nine months ended September 30, 2021 and 2020. Such adjustments are normal and recurring in nature unless otherwise noted.

Dominion Energy Questar Pipeline makes certain estimates and assumptions in preparing its Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues, expenses and cash flows for the periods presented. Actual results may differ from those estimates.

Dominion Energy Questar Pipeline’s Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of its wholly-owned subsidiaries. Dominion Energy Questar Pipeline reports certain investments using the equity method of accounting.

The results of operations for interim periods are not necessarily indicative of the results expected for the full year. Information for quarterly periods is affected by seasonal variations in sales, rate changes, purchased gas and other expenses and other factors.

Certain amounts in Dominion Energy Questar Pipeline’s 2020 Consolidated Financial Statements and Notes have been reclassified to conform to the 2021 presentation for comparative purposes. The reclassifications did not affect Dominion Energy Questar Pipeline’s net income, total assets, liabilities, equity or cash flows.

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Cash, Restricted Cash and Equivalents

The following table provides a reconciliation of the total cash, restricted cash and equivalents reported within Dominion Energy Questar Pipeline’s Consolidated Balance Sheets to the corresponding amounts reported within Dominion Energy Questar Pipeline’s Consolidated Statements of Cash Flows:

Note 3. Operating Revenue

Dominion Energy Questar Pipeline’s operating revenue consists of the following:

The table below discloses the aggregate amount of the transaction price allocated to fixed-price performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period and when Dominion Energy Questar Pipeline expects to recognize this revenue. These revenues relate to contracts containing fixed prices where Dominion Energy Questar Pipeline will earn the associated revenue over time as it stands ready to perform services provided. This disclosure does not include revenue related to performance obligations that are part of a contract with original durations of one year or less. In addition, this disclosure does not include expected consideration related to performance obligations for which Dominion Energy Questar Pipeline elects to recognize revenue in the amount it has a right to invoice.

Contract liabilities represent an entity’s obligation to transfer goods or services to a customer for which the entity has received consideration, or the amount that is due, from the customer. At September 30, 2021 and December 31, 2020, Dominion Energy Questar Pipeline’s contract liability balances were $3.2 million and $3.8 million, respectively, of which $2.5 million and $2.7 million, respectively, is included in other deferred credits and other liabilities in Dominion Energy Questar Pipeline’s Consolidated Balance Sheets. During the nine months ended September 30, 2021 and 2020, $0.9 million and $0.5 million, respectively, of revenue was recognized from the beginning contract liability balance as Dominion Energy Questar Pipeline fulfilled its obligations to provide service to its customers.

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Note 4. Equity Method Investment

Dominion Energy Questar Pipeline uses the equity method to account for its 50% noncontrolling partnership interest in White River Hub, a FERC-regulated transporter of natural gas with facilities that connect with six interstate pipeline systems and a major processing plant in Colorado.

The table below summarizes distributions received and income earned from Dominion Energy Questar Pipeline’s equity method investment in White River Hub for the three and nine months ended September 30, 2021 and 2020.

At both September 30, 2021 and December 31, 2020, other receivables in the Consolidated Balance Sheets included $0.4 million of accrued distributions from White River Hub.

At September 30, 2021 and December 31, 2020, the carrying amount of Dominion Energy Questar Pipeline’s investment of $18.4 million and $19.0 million, respectively, equaled its share of underlying equity in net assets.

Note 5. Regulatory Assets and Liabilities

Regulatory assets and liabilities include the following:

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At September 30, 2021, none of Dominion Energy Questar Pipeline’s regulatory assets were earning a return. With the exception of certain items discussed above, the majority of these expenditures are expected to be recovered within the next year.

Note 6. Regulatory Matters

FERC regulates the transportation and sale for resale of natural gas in interstate commerce under the NGA and the Natural Gas Policy Act of 1978, as amended. Under the NGA, FERC has authority over rates, terms and conditions of services performed by Dominion Energy Questar Pipeline. FERC also has jurisdiction over siting, construction and operation of interstate natural gas pipeline facilities.

There have been no significant developments regarding regulatory matters disclosed in Note 8 to Dominion Energy Questar Pipeline’s Consolidated Financial Statements for the year ended December 31, 2020.

Note 7. Variable Interest Entities

There have been no significant changes regarding the entities Dominion Energy Questar Pipeline considers VIEs as described in Note 10 to Dominion Energy Questar Pipeline’s Consolidated Financial Statements for the year ended December 31, 2020.

DEQPS, an affiliated VIE, provides marketing and operational services to certain Dominion Energy subsidiaries, including Dominion Energy Questar Pipeline, as a subsidiary service company. Dominion Energy Questar Pipeline purchased shared services from DEQPS of $8.3 million and $7.1 million for the three months ended September 30, 2021, and 2020, respectively, and $21.7 million and $20.8 million for the nine months ended September 30, 2021 and 2020, respectively. The Consolidated Balance Sheets at September 30, 2021 and December 31, 2020 include amounts due to DEQPS for such services of $3.8 million and $31.9 million, respectively.

DES, an affiliated VIE, provides administrative, management and other services to Dominion Energy and its subsidiaries as a subsidiary service company. Dominion Energy Questar Pipeline purchased shared services from DES of $2.1 million and $2.0 million for the three months ended September 30, 2021 and 2020, respectively, and $5.6 million and $6.8 million for the nine months ended September 30, 2021and 2020, respectively. The Consolidated Balance Sheets at September 30, 2021 and December 31, 2020 include amounts due to DES for such services of $3.1 million and $2.9 million, respectively.

Note 8. Significant Financing Transactions

Dominion Energy Questar Pipeline’s debt instruments are reported at historical cost. At September 30, 2021 and December 31, 2020, the carrying amount of Dominion Energy Questar Pipeline’s outstanding debt was $425.7 million and $425.5 million, respectively. At September 30, 2021 and December 31, 2020, the fair value of Dominion Energy Questar Pipeline’s outstanding debt was $468.3 million and $461.4 million, respectively. The estimated fair values have been determined using available market information and valuation methodologies considered appropriate by management. The fair values were calculated using market interest rates currently available for issuance of debt with similar terms and remaining maturities. The fair value measurement is classified as Level 2.

Note 9. Commitments and Contingencies

As a result of issues generated in the ordinary course of business, Dominion Energy Questar Pipeline may be involved in legal proceedings before various courts and periodically subject to governmental examinations (including by FERC), inquiries and investigations. Certain legal proceedings and governmental examinations involve demands for unspecified amounts of damages, are in an initial procedural phase, involve uncertainty as to the outcome of pending appeals or motions, or involve significant factual issues that need to be resolved, such that it is not possible for Dominion Energy Questar Pipeline to estimate a range of possible loss. For such matters that Dominion Energy Questar Pipeline cannot estimate, a statement to this effect is made in the description of the matter. Other matters may have progressed sufficiently through the litigation or investigative processes such that Dominion Energy Questar Pipeline is able to estimate a range of possible loss. For legal proceedings and governmental examinations for which Dominion Energy Questar Pipeline is able to reasonably estimate a range of possible losses, an estimated range of possible loss is provided, in excess

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of the accrued liability (if any) for such matters. Estimated ranges of loss are inclusive of legal fees and net of any anticipated insurance recoveries. Any estimated range is based on currently available information and involves elements of judgment and significant uncertainties. Any accrued liability is recorded on a gross basis with a receivable also recorded for any probable insurance recoveries. Any estimated range of possible loss may not represent Dominion Energy Questar Pipeline’s maximum possible loss exposure. The circumstances of such legal proceedings and governmental examinations will change from time to time and actual results may vary significantly from the current estimate. For current proceedings not specifically reported below, management does not anticipate that the liabilities, if any, arising from such proceedings would have a material effect on Dominion Energy Questar Pipeline’s financial position, liquidity or results of operations.

In April 2019, legislation was signed in Colorado that significantly amended the Oil and Gas Conservation Act, set a new mission of the Oil and Gas Conservation Commission and called for 12 future rulemakings. One new rulemaking establishing a methane performance program for natural gas transmission and storage compressor stations has been finalized that could have a material impact on Dominion Energy Questar Pipeline. In December 2020, Dominion Energy Questar Pipeline implemented a methane best management plan and began collecting emissions inventory information for facilities in Colorado which will be submitted annually. Dominion Energy Questar Pipeline is still evaluating whether potential impacts on results of operations, financial condition and/or cash flows related to this matter will be material. The other rulemakings are in the initial procedural phase and the outcome is uncertain, therefore, Dominion Energy Questar Pipeline cannot predict the impact to its results of operations, financial condition and/or cash flows.

Surety Bonds

At September 30, 2021, Dominion Energy Questar Pipeline had purchased $4.3 million of surety bonds. Under the terms of surety bonds, Dominion Energy Questar Pipeline is obligated to indemnify the respective surety bond company for any amounts paid.

Note 10. Credit Risk

Dominion Energy Questar Pipeline’s policy for credit risk is disclosed in Note 13 to Dominion Energy Questar Pipeline’s Consolidated Financial Statements for the year ended December 31, 2020.

Dominion Energy Questar Pipeline provides service to approximately 70 customers, including storage customers, marketers or end-users, power generators and utilities. The two largest customers comprised approximately 47% of the total operating revenues for both the three and nine months ended September 30, 2021, with Dominion Energy Questar Pipeline’s largest customer (an affiliate) representing approximately 33% and 34% of such amounts, respectively. The two largest customers comprised approximately 46% of the total operating revenues for both the three and nine months ended September 30, 2020, with Dominion Energy Questar Pipeline’s largest customer (an affiliate) representing approximately 33% and 34% of such amounts during the periods.

Note 11. Related-Party Transactions

Dominion Energy Questar Pipeline engages in related-party transactions primarily with other Dominion Energy subsidiaries (affiliates). Dominion Energy Questar Pipeline receivable and payable balances with affiliates are settled based on contractual terms or on a monthly basis, depending on the nature of the underlying transactions. Dominion Energy Questar Pipeline’s transactions with White River Hub are described in Note 4. Dominion Energy Questar Pipeline participates in Dominion Energy tax sharing agreements as described in Note 15 to Dominion Energy Questar Pipeline’s Consolidated Financial Statements for the year ended December 31, 2020. A discussion of the remaining significant related-party transactions follows.

Transactions with Related Parties

Dominion Energy Questar and other affiliates (including DES) provide accounting, legal, finance and certain administrative and technical services to Dominion Energy Questar Pipeline while DEQPS primarily provides marketing and operational services to Dominion Energy Questar Pipeline, as discussed in Note 7. These costs are included in other operations and maintenance expense in the Consolidated Statements of Income on the basis of direct and allocated methods in accordance with Dominion Energy Questar Pipeline’s services agreements. Where costs incurred cannot be

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determined by specific identification, the costs are generally allocated based on each affiliated company’s proportional share of revenues less product costs; property, plant and equipment; and labor costs for costs from Dominion Energy Questar and based on the proportional level of effort devoted by resources that is attributable to Dominion Energy Questar Pipeline, determined by reference to number of employees, salaries and wages and other similar measures for the relevant DES service. Management believes that the allocation methods are reasonable.

Dominion Energy Questar Pipeline provides certain services to related parties including transportation and storage. The billed amounts of these services are allocated based on usage. Management believes that the allocation method is reasonable. In addition, Dominion Energy Questar Pipeline purchases transportation services from White River Hub. The amounts of these services follow:

Natural Gas Imbalances

Dominion Energy Questar Pipeline maintains natural gas imbalances with Questar Gas. The imbalance receivable from Questar Gas was $0.3 million at September 30, 2021. The imbalance payable to Questar Gas was $0.1 million at December 31, 2020.

Unbilled Revenue

Affiliated receivables at September 30, 2021 and December 31, 2020 included $7.2 million and $7.4 million, respectively, of accrued unbilled revenue based on estimated amounts of services provided but not yet billed to an affiliate.

Credit Agreement

In November 2020, Dominion Energy Questar Pipeline entered into a $100.0 million intercompany revolving credit agreement with Dominion Energy, of which $9.1 million was outstanding at September 30, 2021. No amount was outstanding at December 31, 2020.

Note 12. Income Taxes

Dominion Energy Questar Pipeline’s effective tax rate for the nine months ended September 30, 2021 is 21.3% compared to 13.9% for the nine months ended September 30, 2020. The effective tax rate for the nine months ended September 30, 2020 includes a prior period adjustment attributable to the 2019 change in tax status of $6.5 million.

Dominion Energy Questar Pipeline’s deferred taxes will reverse at the weighted average rate used to originate the deferred tax liability, which in some cases will be 35%. Dominion Energy Questar Pipeline has recorded an estimate of excess deferred income tax amortization in 2021. The reversal of these excess deferred income taxes will impact the effective tax rate and may impact rates charged to customers.

In January 2020, the state of Utah repealed legislation passed in December of 2019 which lowered the corporate income tax rate. As a result, Dominion Energy Questar Pipeline’s 2020 income tax expense reflects the reversal of previously remeasured accumulated deferred income taxes. See Note 15 to Dominion Energy Questar Pipeline’s Consolidated Financial Statements for the year ended December 31, 2020 for further details.

As of September 30, 2021, there are no unrecognized tax benefits.

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Note 13. Operating Segment

Dominion Energy Questar Pipeline manages its daily operations through one primary operating segment: Gas Transmission & Storage. It also reports a Corporate and Other segment that primarily includes items attributable to its operating segment that are not included in profit measures evaluated by executive management in assessing the segment’s performance or in allocating resources.

The following table presents segment information pertaining to Dominion Energy Questar Pipeline’s operations:

Note 14. Subsequent Events

Dominion Energy Questar Pipeline has evaluated subsequent events through the date that these consolidated financial statements were available to be issued on November 17, 2021.

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Exhibit 99.2

Dominion Energy Questar Pipeline, LLC

Consolidated Financial Statements

Fiscal Years Ended December 31, 2020, 2019 and 2018

with Independent Auditors’ Report

Dominion Energy Questar Pipeline, LLC

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GLOSSARY OF TERMS

The following abbreviations or acronyms used in this document are defined below:

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				Deloitte & Touche LLP 901 E. Byrd St Suite 820 Richmond, VA 23219 USA   www.deloitte.com

INDEPENDENT AUDITORS’ REPORT

To the President –Gas Distribution

Dominion Energy Questar Pipeline, LLC

We have audited the accompanying consolidated financial statements of Dominion Energy Questar Pipeline, LLC and its subsidiaries (the “Company”), which comprise the consolidated balance sheets at December 31, 2020 and 2019, and the related consolidated statements of income, equity, and cash flows for each of the three years in the period ended December 31, 2020, and the related notes to the consolidated financial statements.

Management’s Responsibility for the Consolidated financial statements

Management is responsible for the preparation and fair presentation of these consolidated financial statements in accordance with accounting principles generally accepted in the United States of America; this includes the design, implementation, and maintenance of internal control relevant to the preparation and fair presentation of consolidated financial statements that are free from material misstatement, whether due to fraud or error.

Auditors’ Responsibility

Our responsibility is to express an opinion on these consolidated financial statements based on our audits. We conducted our audits in accordance with auditing standards generally accepted in the United States of America. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free from material misstatement.

An audit involves performing procedures to obtain audit evidence about the amounts and disclosures in the consolidated financial statements. The procedures selected depend on the auditor’s judgment, including the assessment of the risks of material misstatement of the consolidated financial statements, whether due to fraud or error. In making those risk assessments, the auditor considers internal control relevant to the Company’s preparation and fair presentation of the consolidated financial statements in order to design audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control. Accordingly, we express no such opinion. An audit also includes evaluating the appropriateness of accounting policies used and the reasonableness of significant accounting estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements.

We believe that the audit evidence we have obtained is sufficient and appropriate to provide a basis for our audit opinion.

Opinion

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of Dominion Energy Questar Pipeline, LLC and its subsidiaries at December 31, 2020 and 2019, and the results of their operations and their cash flows for each of the three years in the period ended December 31, 2020 in accordance with accounting principles generally accepted in the United States of America.

April 14, 2021

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Dominion Energy Questar Pipeline, LLC

Consolidated Statements of Income

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

5

Dominion Energy Questar Pipeline, LLC

Consolidated Balance Sheets

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

6

Dominion Energy Questar Pipeline, LLC

Consolidated Balance Sheets (continued)

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

7

Dominion Energy Questar Pipeline, LLC

Consolidated Statements of Equity

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

8

Dominion Energy Questar Pipeline, LLC

Consolidated Statements of Cash Flows

The accompanying notes are an integral part of Dominion Energy Questar Pipeline’s Consolidated Financial Statements.

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Notes to Consolidated Financial Statements

NOTE 1. DESCRIPTION OF BUSINESS

Dominion Energy Questar Pipeline is a limited liability company owned by Dominion Energy Questar (effective November 2020) which is a wholly-owned subsidiary of Dominion Energy. Dominion Energy Questar Pipeline owns and operates interstate natural gas pipeline and storage facilities in the western U.S., including a 50% noncontrolling partnership interest in White River Hub. Dominion Energy Questar Pipeline’s operations are primarily regulated by FERC.

In July 2020, Dominion Energy entered into an agreement to sell substantially all of its gas transmission and storage operations, including Dominion Energy Questar Pipeline, to BHE. In October 2020, pursuant to a provision in the agreement with BHE, Dominion Energy elected to exclude Dominion Energy Questar Pipeline from the transaction as approval under the Hart-Scott-Rodino Act had not been obtained by mid-September 2020. Concurrently in October 2020, Dominion Energy entered into an agreement with BHE for the sale of Dominion Energy Questar Pipeline once receipt of approval is obtained under the Hart-Scott-Rodino Act, which is currently anticipated in the first half of 2021. Upon closing, Dominion Energy Questar Pipeline will become an indirect wholly-owned subsidiary of BHE.

NOTE 2. SIGNIFICANT ACCOUNTING POLICIES

General

Dominion Energy Questar Pipeline makes certain estimates and assumptions in preparing its Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues, expenses, and cash flows for the periods presented. Actual results may differ from those estimates.

Dominion Energy Questar Pipeline’s Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of its wholly-owned subsidiaries. Dominion Energy Questar Pipeline reports certain investments using the equity method of accounting.

Dominion Energy Questar Pipeline reports certain contracts and instruments at fair value. The carrying values of customer and other receivables, affiliated receivables, accounts payable and payables to affiliates are estimated to be substantially the same as their fair values at December 31, 2020 and 2019.

Certain amounts in Dominion Energy Questar Pipeline’s historical Consolidated Financial Statements and Notes have been reclassified to conform to the current presentation for comparative purposes. The reclassifications did not affect Dominion Energy Questar Pipeline’s net income, total assets, liabilities, equity or cash flows.

Operating Revenue

Operating revenue is recorded on the basis of services rendered, commodities delivered or contracts settled and includes amounts yet to be billed to customers. Dominion Energy Questar Pipeline is currently generating significant revenue and earnings from annual reservation payments under firm peaking storage and firm transportation contracts. Straight-fixed-variable rate designs are used to allow for recovery of substantially all fixed costs in demand or reservation charges, thereby reducing the earnings impact of volume changes on gas transportation and storage operations. Customer and other and affiliated receivables at December 31, 2020 and 2019 included $20.2 million and $22.1 million, respectively, of accrued unbilled revenue based on estimated amounts of services provided but not yet billed to its customers. See Note 14 for amounts related to affiliates.

Dominion Energy Questar Pipeline receives upfront payment for certain storage services it provides to customers, which are considered to be contract liabilities. These payments are amortized to revenue over the term of the contract.

The primary types of sales and service activities reported as operating revenue for Dominion Energy Questar Pipeline are as follows:

Revenue from Contracts with Customers

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Other Revenue

Transportation and storage contracts are primarily stand-ready service contracts that include fixed reservation and variable usage fees. Fixed fees are recognized ratably over the life of the contract as the stand-ready performance obligations are satisfied, while variable usage fees are recognized when Dominion Energy Questar Pipeline has a right to consideration from a customer in an amount that corresponds directly with the value to the customer of the performance obligation completed to date. Substantially all of Dominion Energy Questar Pipeline’s revenues are derived from performance obligations satisfied over time, rather than recognized at a single point in time. The contract with the customer states the final terms of the sale, including the description, quantity and price of each product or service purchased. Payment for most sales and services varies by contract type, but is typically due within a month of billing.

Dominion Energy Questar Pipeline typically receives or retains NGLs and natural gas from customers when providing natural gas processing, transportation or storage services. Dominion Energy Questar Pipeline records the fair value of NGLs received as service revenue recognized over time and recognizes revenue from the subsequent sale of the NGLs to customers upon delivery. Dominion Energy Questar Pipeline typically retains natural gas under certain transportation service arrangements that are intended to facilitate performance of the service and allow for natural losses that occur. As the intent of the allowance is to enable fulfillment of the contract rather than to provide compensation for services, the fuel allowance is not included in revenue.

Purchased Gas and Other – Deferred Costs

The difference between purchased gas and other expenses and the related levels of recovery for these expenses in current rates are deferred and matched against recoveries in future periods. The deferral of costs in excess of current period fuel rate recovery is recognized as a regulatory asset, while rate recovery in excess of current period fuel expenses is recognized as a regulatory liability.

Income Taxes

Effective December 1, 2016, to December 31, 2018, Dominion Energy Questar Pipeline was treated as a component of Dominion Energy Midstream. Through January 2019, Dominion Energy Midstream was organized as an MLP, a pass-through entity for U.S. federal and state income tax purposes. Dominion Energy Midstream was organized as a limited partnership not subject to income tax for federal and state income tax purposes. Accordingly, Dominion Energy Questar Pipeline’s Consolidated Financial Statements do not include income taxes for the period December 1, 2016 through November 4, 2019. Effective November 4, 2019, Dominion Energy Questar Pipeline is treated as a division of its corporate parent and reflects a cumulative provision for income taxes in its Consolidated Financial Statements.

A consolidated federal income tax return is filed for Dominion Energy and its subsidiaries, including Dominion Energy Questar Pipeline. Where applicable, combined income tax returns for Dominion Energy and its subsidiaries are filed in various states.

Beginning in November 2019, Dominion Energy Questar Pipeline participates in intercompany tax sharing agreements with Dominion Energy and its subsidiaries. Current income taxes are based on taxable income or loss and credits determined on a separate company basis. At December 31, 2020, Dominion Energy Questar Pipeline has an income tax-related affiliate receivable of $1.4 million, comprised of $1.1 million of federal income taxes and $0.3 million of state income taxes due from Dominion Energy. At December 31, 2019, Dominion Energy Questar Pipeline has an income tax-related affiliate payable of $4.2 million, comprised of $3.7 million of federal income taxes and $0.5 million of state income taxes due to Dominion Energy.

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Under the agreements, if a subsidiary incurs a tax loss or earns a credit, recognition of current income tax benefits is limited to refunds of prior year taxes obtained by the carryback of the net operating loss or credit or to the extent the tax loss or credit is absorbed by the taxable income of other Dominion Energy consolidated group members. Otherwise, the net operating loss or credit is carried forward and is recognized as a deferred tax asset until realized.

Accounting for income taxes involves an asset and liability approach. Deferred income tax assets and liabilities are provided, representing future effects on income taxes for temporary differences between the bases of assets and liabilities for financial reporting and tax purposes. Accordingly, deferred taxes are recognized for the future consequences of different treatments used for the reporting of transactions in financial accounting and income tax returns. Dominion Energy Questar Pipeline establishes a valuation allowance when it is more-likely-than-not that all, or a portion, of a deferred tax asset will not be realized. Dominion Energy Questar Pipeline has $0.9 million of valuation allowances as of both December 31, 2020 and 2019.

Dominion Energy Questar Pipeline recognizes positions taken, or expected to be taken, in income tax returns that are more-likely-than-not to be realized, assuming that the position will be examined by tax authorities with full knowledge of all relevant information.

If it is not more-likely-than-not that a tax position, or some portion thereof, will be sustained, the related tax benefits are not recognized in the financial statements. Unrecognized tax benefits may result in an increase in income taxes payable, a reduction of income tax refunds receivable or changes in deferred taxes. Also, when uncertainty about the deductibility of an amount is limited to the timing of such deductibility, the increase in income taxes payable (or reduction in income tax refunds receivable) is accompanied by a decrease in deferred tax liabilities. Except when such amounts are presented net with amounts receivable from or amounts prepaid to tax authorities, noncurrent income taxes payable related to unrecognized tax benefits are reported in the Consolidated Balance Sheet and current payables are included in accrued interest and taxes in the Consolidated Balance Sheet. Dominion Energy Questar Pipeline does not have any unrecognized tax benefits.

Dominion Energy Questar Pipeline recognizes interest on underpayments and overpayments of income taxes in interest expense and other income, respectively. Penalties are also recognized in other income.

Cash, Restricted Cash and Equivalents

Cash, restricted cash and equivalents include cash on hand, cash in banks and temporary investments purchased with an original maturity of three months or less.

Current banking arrangements generally do not require checks to be funded until they are presented for payment. At December 31, 2020 and 2019, accounts payable included $1.0 million and $0.8 million, respectively, of checks outstanding but not yet presented for payment.

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Restricted Cash and Equivalents

Beginning in 2018, Dominion Energy Questar Pipeline holds restricted cash balances that primarily consist of amounts held for certain customer deposits as allowed under FERC gas tariffs. The following table provides a reconciliation of the total cash, restricted cash, and equivalents reported within Dominion Energy Questar Pipeline’s Consolidated Balance Sheets to the corresponding amounts reported within Dominion Energy Questar Pipeline’s Consolidated Statements of Cash Flows for the years ended December 31, 2020, 2019 and 2018:

Distributions from Equity Method Investee

Dominion Energy Questar Pipeline holds an investment that is accounted for under the equity method of accounting. Dominion Energy Questar Pipeline classifies distributions from its equity method investee as either cash flows from operating activities or cash flows from investing activities in the Consolidated Statements of Cash Flows according to the nature of the distribution. Distributions received are classified on the basis of the nature of the activity of the investee that generated the distribution as either a return on investment (classified as cash flows from operating activities) or a return of an investment (classified as cash flows from investing activities) when such information is available to Dominion Energy Questar Pipeline.

Equity Method Investment

Investment in an affiliate where Dominion Energy Questar Pipeline exercises significant influence over the operating activities of the entity, but does not control the entity, is accounted for using the equity method. Such investment is included in equity method investment in the Consolidated Balance Sheets. Dominion Energy Questar Pipeline records equity method adjustments in earnings from equity method investee in the Consolidated Statements of Income, including its proportionate share of investee income or loss and other adjustments required by the equity method.

Dominion Energy Questar Pipeline periodically evaluates its equity method investment to determine whether a decline in fair value should be considered other-than-temporary. If a decline in fair value of an investment is determined to be other-than-temporary, the investment is written down to its fair value at the end of the reporting period.

Property, Plant and Equipment

Property, plant and equipment, including additions and replacements, is recorded at original cost, consisting of labor and materials and other costs such as asset retirement costs, capitalized interest, AFUDC and overhead costs. The cost of repairs and maintenance, including minor additions and replacements, is charged to expense as it is incurred.

In 2020, 2019 and 2018, Dominion Energy Questar Pipeline capitalized interest costs and AFUDC of $0.1 million, $1.0 million and $0.9 million, respectively, to property, plant and equipment.

The undepreciated cost of property, less salvage value, is generally charged to accumulated depreciation at retirement. Cost of removal collections not representing AROs are recorded as regulatory liabilities.

Depreciation of property, plant and equipment is computed on the straight-line method based on projected service lives. Depreciation rates on property, plant and equipment are as follows: