Northern Virginia Water Supply Plan


In November 2005, the Commonwealth of Virginia enacted the Local and Regional Water Supply Planning (WSP) Regulation (9 VAC 25-780-10) 

  • The purpose of the Regulation is to:  
    • ensure adequate and safe drinking water
    • encourage, promote, and protect all other beneficial uses of the Commonwealth’s water resources; and 
    • encourage, promote, and develop incentives for alternative water sources
  • Establishes required planning process and criteria that local governments shall use in the development of local or regional WSPs
  •  WSPs must encompass a planning horizon of 30 to 50 years and address both surface and groundwater use
  • After a WSP is submitted to and reviewed by DEQ, the State Water Control Board will make a determination as to its compliance with the regulation
  • WSPs must be reviewed by the locality every 5 years and revised and resubmitted if necessary; all WSP’s must be reviewed, revised, and resubmitted to DEQ every 10 years

At the request of the local governments in northern Virginia, the Regional Commission has been coordinating the development of the Northern Virginia Regional Water Supply Plan:

  • Plan Participants:  
    • Every County, City and Town within Northern Virginia with the exception of the Town of Hillsboro. The Plan is a partnership between Jurisdictions, local Water Authorities and the Regional Commission
    • Water Authorities are the lead for data collection within Jurisdictions service areas
    • The Regional Commission is lead for data collection for Non-municipal Community Water Systems and Wells
  • The Regional Commission obtained assistance from the MWCOG and the ICPRB by aligning the Regional Population Projections and the Co-op Potomac River Forecasts to meet the local government’s planning horizon date needs
  • Components of the Regional Water Supply Plan are required to include:
    1. An inventory of existing water resources
    2. An assessment of existing water use
    3. An assessment of projected water demand
    4. A statement of need if water supply demands exceed source availability within the planning horizon
    5. An analysis of alternatives to address projected source water deficits if they exist
    6. A description of water demand management actions
    7. A drought Response and Contingency Plan

2011 Northern Virginia Regional Water Supply Plan

The Regional Commission along with the participating local governments and Water Authorities are entering the final stages of the Plan’s development.  A copy of the Northern Virginia Regional Water Supply Plan can be obtained by clicking on the following links. Due to the size of the document, hard copies of the Plan will not be available for distribution. Electronic copies of the individual Chapters can be obtained by clicking on the links. In order to view the documents you will need to have Adobe Acrobat installed on your computer

Executive Summary
Section 1 – Introduction
Section 2 - Evaluation of Existing Water Supply
Section 3 - Existing Water Uses
Section 4 - Natural Resources
Section 5 - Demand Projections
Section 6 - Water Demand Management
Section 7 - Drought Response and Contingency Plan
Section 8 - Statement of Need
Section 9 - Water Source Alternatives Evaluation
Section 10 – References
Section 11 – Acronyms
Appendix A - SWAP Susceptibility Rankings
Appendix B - Available Water Source and Use Forms
Appendix C - Demand Projections
Appendix D - Drought Response and Contingency Plan
Appendix E - Water Demand Management Information
Appendix F - ICPRB Report
Appendix G - Natural Resource Information

Interim Update – 2018 Northern Virginia Water Supply Plan

While the Northern Virginia Regional Commission did not gather any statistical data from any of the regions water supply purveyors for this interim update, a status of water demand for the majority of northern Virginia can be seen in the 2015 Washington Metropolitan Area Water Supply Study by the Interstate Commission on the Potomac (ICPRB). Water use in the 2015 Washington Metropolitan Area (WMA) has held steady during the past two decades, averaging 466 million gallons per day (MGD) in recent years (2009-2013). Though the WMA population rose 18 percent from 1990-2015, from 3.9 to 4.6 million people, its water demands have essentially remained constant over that period due to falling per household and per employee use. This decline in unit use is consistent with trends seen throughout the United States. Both the 2035 and 2040 forecasts are 19 percent lower than the forecasts in ICPRB’s 2010 study. This significant drop is primarily due to the new estimates for future per household and per employee use reductions.

There have been a number of changes to the supplier service areas since the 2011 Northern Virginia Water Supply Report. In November 2012, Loudoun Water, a wholesale customer of Fairfax Water, obtained a permit from the Virginia Department of Environmental Quality to build and operate a 40 MGD water supply intake on the Potomac River and a new water treatment plant. Under the permit, when this system is completed it will provide up to 20 MGD of Loudoun Water’s demand. Loudoun Water will also continue to purchase water to meet its needs from Fairfax Water. In January 2014, the City of Fairfax and the City of Falls Church were incorporated into Fairfax Water’s retail service area. The City of Fairfax formerly owned and operated its own municipal water supply system. The City of Falls Church was formerly a wholesale customer of Aqueduct. To supply water to the City of Falls Church, Fairfax Water now receives wholesale water from Aqueduct. While these are changes are shifts in ownership and delivery, they do not reflect changes to the overall demand in northern Virginia.

A fully documented picture of water supply demand and future projections will be detailed in the upcoming 2023 update to the Plan.

ICPRB Report 2015