Exhibit 99.1

WGL Holdings, Inc. Reports Fiscal Year 2013 Financial Results;

Issues Fiscal Year 2014 Guidance

Consolidated Results

WGL Holdings, Inc. (WGL), the parent company of Washington Gas Light Company (Washington Gas) and other energy-related subsidiaries, today reported net income determined in accordance with generally accepted accounting principles in the United States of America (GAAP) for the fiscal year ended September 30, 2013 of $80.3 million, or $1.55 per share, compared to net income of $139.8 million, or $2.71 per share, reported for the fiscal year ended September 30, 2012.

For the quarter ended September 30, 2013, we reported a net loss determined in accordance with GAAP of ($51.6) million, or ($1.00) per share, compared to net income of $7.7 million, or $0.15 per share, reported for the same quarter of the prior fiscal year.

Financial performance is also evaluated based on non-GAAP operating earnings (loss). Non-GAAP operating earnings (loss) adjusts for the effects of applying GAAP to certain transactions or classes of transactions that are not representative of the on-going operating earnings of the company. Refer to “Use of Non-GAAP Operating Earnings (Loss)” and supporting reconciliations attached to this news release for a detailed discussion of management’s use of non-GAAP operating earnings, as well as reconciliations of net income determined in accordance with GAAP to non-GAAP operating earnings (loss) for both our consolidated and segment results.

For the fiscal year ended September 30, 2013, non-GAAP operating earnings were $119.8 million, or $2.31 per share, compared to non-GAAP operating earnings of $138.4 million, or $2.68 per share, for the prior fiscal year. For the fourth quarter of fiscal year 2013, our non-GAAP operating loss was ($28.2) million, or ($0.55) per share, compared to a non-GAAP operating loss of ($5.0) million, or ($0.10) per share, for the same quarter of the prior fiscal year.

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“The full-year results for our regulated utility business reflected the positive impact of recent regulatory actions and O&M management, and exceeded our expectations for the year,” said Terry McCallister, Chairman and Chief Executive Officer of WGL. “This segment of our business is performing well and will benefit in the future from continued customer growth and rate base growth driven by accelerated pipe replacement programs in all three of our jurisdictions.”

“Among our non-utility businesses, our commercial energy systems business is also performing well and is meeting our objective of growing our asset-based renewable energy investments. Market conditions and external costs experienced at both our midstream and retail businesses adversely impacted the expected growth during the year from this part of our portfolio. We believe the challenges in these businesses are manageable and with growth opportunities arising for pipeline investments, we are still positioned to achieve our long term growth objective.”

Fiscal Year and Fourth Quarter Results by Business Segment

Regulated Utility Segment

For the quarter ended September 30, 2013, our regulated utility segment reported a seasonal net loss of ($39.7) million, or ($0.77) per share, compared to a net loss of ($1.2) million, or ($0.02) per share, reported for the fourth quarter of the prior fiscal year. After adjustments, the non-GAAP operating loss for the regulated utility segment was ($22.2) million, or ($0.43) per share, for the quarter ended September 30, 2013, compared to a non-GAAP operating loss of ($12.6) million, or ($0.24) per share, for the same quarter of the prior fiscal year. The quarter comparison of non-GAAP operating losses reflect higher operating costs associated with employee benefits, a higher effective tax rate and lower asset optimization margins. Partially offsetting these unfavorable variances were slightly higher revenues from new base rates in the District of Columbia.

For the fiscal year ended September 30, 2013, our regulated utility segment reported net income of $71.8 million, or $1.39 per share, compared to net income of $109.7 million, or $2.13 per share, for the prior fiscal year. After adjustments, non-GAAP operating earnings for the regulated utility segment were $99.8 million, or $1.93 per share, for the fiscal year ended September 30, 2013, compared to non-GAAP operating earnings of $104.4 million, or $2.02 per share, for the prior fiscal year. The year-over-year change in non-GAAP operating earnings reflect lower recovery of carrying costs on storage gas inventory, higher pension costs and higher depreciation expense resulting from the growth in our investment in utility plant. Partially offsetting these unfavorable variances were higher revenues resulting from customer growth, new base rates in Maryland and the District of Columbia, accelerated pipeline replacement surcharges, favorable effects of changes in natural gas consumption patterns and lower uncollectible accounts expense.

Retail Energy-Marketing Segment

For the quarter ended September 30, 2013, the retail energy-marketing segment reported net income of $2.5 million, or $0.05 per share, compared to net income of $14.4 million, or $0.28 per share, reported for the same quarter of the prior fiscal year. Non-GAAP operating earnings for the retail energy-marketing segment were $0.6 million, or $0.01 per share, for the quarter ended September 30, 2013, compared to non-GAAP operating earnings of $8.9 million, or $0.17 per share, for the same quarter of the prior fiscal year. The quarter comparison of non-GAAP operating earnings reflect lower realized electric unit margins due to higher costs to customers under fixed contract pricing from the regional power grid operator (PJM), partially offset by higher natural gas unit margins on favorable supply timing issues. Operating expenses for the quarter were higher primarily due to higher customer acquisition costs.

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For the fiscal year ended September 30, 2013, the retail energy-marketing segment reported net income of $33.0 million, or $0.64 per share, compared to net income of $39.3 million, or $0.76 per share, reported for the prior fiscal year. Non-GAAP operating earnings for the retail energy-marketing segment were $30.4 million, or $0.59 per share, for the fiscal year ended September 30, 2013, compared to non-GAAP operating earnings of $36.2 million, or $0.70 per share, for the prior fiscal year.

The fiscal year comparison of non-GAAP operating earnings reflects lower electricity margins due to the timing differences in margin recognition as well as higher costs associated with fixed price contracts partially offset by higher natural gas margins. Natural gas margins were higher primarily due to higher volumes resulting from colder weather and increased margins on portfolio optimization activities. Operating expenses decreased year-over-year due to lower uncollectible accounts expense and purchase of receivables costs, partially offset by higher salaries and benefits.

Commercial Energy Systems Segment

For the quarter ended September 30, 2013, the commercial energy systems segment reported net income of $1.1 million, or $0.02 per share, compared to net income of $0.9 million, or $0.02 per share, for the same quarter of the prior fiscal year. For the fiscal year ended September 30, 2013, the commercial energy systems segment reported net income of $3.0 million, or $0.06 per share, compared to net income of $2.4 million, or $0.05 per share, for the same period of the prior fiscal year. The increase in earnings is primarily due to higher revenue from commercial solar projects in the current period partially offset by continued weakness in the federal energy efficiency contracting business. There were no non-GAAP adjustments for this segment for any of the periods presented.

Midstream Energy Services Segment

The wholesale energy solutions segment has been renamed the midstream energy services segment. For the quarter ended September 30, 2013, the midstream energy services segment reported a net loss of ($11.8) million, or ($0.23) per share, compared to a net loss of ($5.6) million, or ($0.11) per share, for the same period of the prior fiscal year. Non-GAAP operating losses for the midstream energy services segment were ($3.9) million, or ($0.07) per share, compared to an operating loss of ($1.5) million, or ($0.03) per share, for the same period of the prior fiscal year. For the fiscal year ended September 30, 2013, the midstream energy services segment reported a net loss of ($18.8) million, or ($0.36) per share, compared to a net loss of ($9.1) million, or ($0.18) per share, for the same period of the prior fiscal year. Midstream energy services had a non-GAAP operating loss of ($5.3) million, or ($0.10) per share, compared to an operating loss of ($2.2) million, or ($0.04) per share, for the same period of the prior fiscal year.

The non-GAAP comparisons for both the quarter and fiscal year primarily reflect costs incurred related to the investment in the Constitution Pipeline project, continued compression of storage spreads and higher operation and maintenance expense as a result of new storage and optimization arrangements.

Other Activities

For the quarter ended September 30, 2013, other activities reported a net loss of ($2.9) million, or ($0.05) per share, compared to a net loss of ($0.7) million, or ($0.02) per share, for the same quarter of the prior fiscal year. There were no non-GAAP adjustments for the three months ended September 30, 2013.

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For the fiscal year ended September 30, 2013, other activities reported a net loss of ($7.9) million, or ($0.16) per share, compared to a net loss of ($2.5) million, or ($0.05) per share, for the prior fiscal year. Other activities reported non-GAAP operating losses of ($7.3) million, or ($0.15) per share, compared to a non-GAAP operating loss of ($2.5) million, or ($0.05) per share, for the same period of the prior fiscal year. The non-GAAP comparisons for both the quarter and year-to-date reflect our corporate branding initiative costs and an increase in our on-going business development activities.

Earnings Outlook

Our GAAP earnings estimate for fiscal year 2014 is in a range of $2.22 per share to $2.42 per share. This estimate includes projected fiscal year 2014 earnings from our regulated utility segment in a range of $1.90 per share to $2.00 per share and projected fiscal year 2014 earnings from our non-utility business segments in a range of $0.32 per share to $0.42 per share.

We are also providing a consolidated earnings estimate for fiscal year 2014 based on non-GAAP operating earnings in a range of $2.15 per share to $2.35 per share. This estimate includes projected fiscal year 2014 non-GAAP operating earnings from our regulated utility segment in a range of $1.83 per share to $1.93 per share and projected fiscal year 2014 non-GAAP operating earnings from our non-utility business segments in a range of $0.32 per share to $0.42 per share. Refer to the “Reconciliation of GAAP Earnings Guidance to Non-GAAP Earnings Guidance” attached to this press release for a reconciliation of our GAAP earnings per share estimate to our estimate based on non-GAAP operating earnings per share.

We assume no obligation to update this guidance. The absence of any statement by us in the future should not be presumed to represent an affirmation of this earnings guidance. For the assumptions underlying this guidance, please refer to the slides accompanying our webcast that will be posted to WGL’s website, www.wglholdings.com.

Other Information

We will hold a conference call at 10:30 a.m. Eastern Time on November 14, 2013, to discuss our fourth quarter and fiscal year 2013 financial results. The live conference call will be available to the public via a link located on WGL’s website, www.wglholdings.com. To hear the live webcast, click on the “Webcast” link located on the home page of the referenced site. The webcast and related slides will be archived on WGL’s website through December 13, 2013.

Headquartered in Washington, D.C., WGL [NYSE: WGL] is a leading source for clean and efficient energy solutions. Through our affiliates and strategic relationships, the Company offers a diverse set of energy sources including natural gas, wind, and solar as well as a range of energy solutions – generation, storage, transportation, distribution, supply, and efficiency – which serve customers in more than 25 states. WGL has five main operating units: Washington Gas Light Company, a regulated natural gas utility serving approximately 1.1 million customers in the metropolitan Washington, D.C. area; Washington Gas Energy Services, Inc., one of the largest natural gas, electricity and green energy suppliers in the Mid-Atlantic; Washington Gas Energy Systems, Inc., a distributed generation and energy efficiency business, offering solar, fuel cell, combined heat and power, and other technologies across the United

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States; WGL Midstream, a midstream energy services business, investing in and optimizing natural gas pipelines and storage facilities in the Midwest and Eastern United States; and Hampshire Gas, a natural gas storage business which owns and operates facilities in and around Hampshire County, West Virginia. As product and service innovation are critical for value creation and sustaining growth, we are continuously increasing our assets and investments in targeted clean energy sectors. This strategy supports WGL’s core business, as well as provides opportunity for growth through partnerships and investments. WGL’s diversity is its strength. We are dedicated to the sustainability of our business, the customers and communities we serve, and the environment. To learn more, visit www.wglholdings.com.

Unless otherwise noted, earnings per share amounts are presented on a diluted basis, and are based on weighted average common and common equivalent shares outstanding.

Please see the attached comparative statements for additional information on our operating results. Also attached to this news release are reconciliations of net income determined in accordance with GAAP to non-GAAP operating earnings (loss) for both our consolidated and segment results as well as reconciliations of our GAAP earnings guidance to our non-GAAP earnings guidance.

Forward-Looking Statements

This news release and other statements by us include forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 with respect to the outlook for earnings, revenues and other future financial business performance or strategies and expectations. Forward-looking statements are typically identified by words such as, but not limited to, “estimates,” “expects,” “anticipates,” “intends,” “believes,” “plans,” and similar expressions, or future or conditional verbs such as “will,” “should,” “would,” and “could.” Although we believe such forward-looking statements are based on reasonable assumptions, we cannot give assurance that every objective will be achieved. Forward-looking statements speak only as of today, and we assume no duty to update them. Factors that could cause actual results to differ materially from those expressed or implied include, but are not limited to, general economic conditions and the factors discussed under the “Risk Factors” heading in our most recent annual report on Form 10-K and other documents we have filed with, or furnished to, the U.S. Securities and Exchange Commission.

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WGL Holdings, Inc.

Consolidated Balance Sheets

(Unaudited)

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WGL Holdings, Inc.

Consolidated Statements of Income

(Unaudited)

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WGL Holdings, Inc.

Consolidated Financial and Operating Statistics

(Unaudited)

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WGL HOLDINGS, INC.

USE OF NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

The attached reconciliations are provided to clearly identify adjustments made to net income calculated in accordance with GAAP to derive non-GAAP operating earnings (loss). Management believes non-GAAP operating earnings (loss) provides a more meaningful representation of our earnings from ongoing operations by adjusting for the effects of: (i) unrealized mark-to-market gains and losses from energy-related derivatives for our regulated utility and retail marketing segments; (ii) unrealized gains (losses) on certain derivatives for the long-term purchase of natural gas for the midstream energy services segment; (iii) certain gains and losses associated with optimizing the utility segment’s capacity assets; (iv) changes in the measured value of our inventory for our midstream energy services segment; (v) the financial effects of warmer-than-normal/colder-than-normal weather that exceeds weather protection for our regulated utility segment; (vi) incremental legal and consulting costs associated with business development activities; and (vii) certain unusual transactions. This presentation facilitates analysis by providing a consistent and comparable measure to help management, investors and analysts better understand and evaluate our operating results and performance trends, to forecast future results and assist in analyzing period-to-period comparisons. Additionally, we use this non-GAAP measure to report to the board of directors and to evaluate management’s performance. The economic substance underlying our adjustments to calculate non-GAAP operating earnings (loss) is as follows:

There are limits in using non-GAAP operating earnings (loss) to analyze our results, as they are not prepared in accordance with GAAP and may be different from non-GAAP financial measures used by other companies. In addition, using non-GAAP operating earnings (loss) per share to analyze our earnings may have limited value as it excludes certain items that may have a material impact on our reported financial results. We compensate for these limitations by providing investors with the attached reconciliations to net income, the most directly comparable GAAP financial measure.

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WGL HOLDINGS, INC. (Consolidating by Segment)

RECONCILIATION OF GAAP NET INCOME (LOSS) TO

NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

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WGL HOLDINGS, INC. (Consolidated by Quarter)

RECONCILIATION OF GAAP NET INCOME (LOSS) TO

NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

Footnotes:

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WGL HOLDINGS, INC. (Consolidated by Quarter)

RECONCILIATION OF GAAP NET INCOME (LOSS) TO

NON-GAAP OPERATING EARNINGS (LOSS)

(Unaudited)

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WGL HOLDINGS, INC.

RECONCILIATION OF GAAP EARNINGS GUIDANCE TO

NON-GAAP EARNINGS GUIDANCE

FISCAL YEAR ENDING SEPTEMBER 30, 2014

Footnotes:

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