The Fairfax County Water Authority (“Fairfax Water”) appreciates the opportunity to comment on the proposed triennial review of water quality standards. 

Fairfax Water is the largest water utility in Virginia, serving one out of every four citizens who obtain their water from public utilities. Nearly two million residents of Northern Virginia, including large portions of Fairfax, Loudoun, and Prince William Counties, the Towns of Herndon and Vienna, Dulles Airport, Ft. Belvoir and the Cities of Falls Church, Fairfax, and Alexandria, depend on Fairfax Water for their drinking water. Fairfax Water relies on the Potomac River and the Occoquan Reservoir as its water supply sources. Fairfax Water also purchases water from the Washington Aqueduct Division of the U.S. Army Corps of Engineers, a water supply sourced from the Potomac River.

The U.S. EPA recognizes that the integration of lake and reservoir management needs, including drinking water supply protection, into Clean Water Act initiatives is an important component of watershed based reservoir protection efforts. Virginia’s Water Quality Standards (WQS) for rivers and reservoirs designated as Public Water Supply (PWS) provides an important function in protecting sources of drinking water, serving as an initial step in a multiple barrier approach to public health protection. The protection of water supply sources is imperative to water utilities continuing to provide safe, high quality drinking water for the residents and businesses of the Commonwealth.

Fairfax Water has identified a few important issues that should be included in the triennial review process:

Sodium Public Water Supply Criteria:  The U.S. Environmental Protection Agency (EPA) 2018 Edition of the Drinking Water Standards and Health Advisories Tables identifies a 20 mg/L advisory level for individuals on a 500 mg/day restricted sodium diet and a 30-60 mg/L taste threshold advisory level. Sodium levels in our supply sources – the Occoquan Reservoir and Potomac River – have risen noticeably over the past decades, with average concentrations more than doubling in the Occoquan Reservoir. During some periods, sodium levels can become elevated in the drinking water and surpass EPA advisory levels for sensitive populations within our community. Fairfax Water’s advanced water treatment process does not have reverse osmosis treatment required to remove salts such as sodium. Without a long–term commitment to manage sources of salt, the residents and businesses in Northern Virginia will eventually bear the cost of removing those constituents from the drinking water supply. Other waterworks in the Commonwealth using freshwater supply sources will inevitably face similar challenges. The Commonwealth needs a long–term strategy to address this problem, focused on source reduction and management. Establishing a sodium water quality standard for freshwater public water supply designated waters is an important part of a comprehensive approach to address this issue. Fairfax Water would welcome the opportunity to discuss other potential sodium strategy ideas with DEQ staff.

PFOA, PFOS and PFAS Public Water Supply Criteria:  In 2016, the EPA issued a lifetime health advisory of 70 ppt for the combined concentration of Perfluorooctanoic acid (PFOA) and Perfluorooctanoic sulfonic acid (PFOS). On January 19, 2021 the EPA made a final regulatory determination to regulate PFOA and PFOS, initiating the process to develop a national primary drinking water regulation for these two chemicals and to further evaluate other PFAS chemicals through the Safe Drinking Water Act. The EPA is also implementing a Per– and Polyfluoroalkyl Substances (PFAS) Action Plan, which includes the development of water quality criteria for PFAS through the Clean Water Act.  Based on these actions, along with Virginia’s efforts to study the occurrence of PFAS in raw water sources and to recommend maximum contaminant levels in drinking water for six PFAS compounds, DEQ needs to establish PFAS compound water quality criterion for PWS designated waters. As with sodium, the Commonwealth needs an approach focused on source reduction and management to address the emerging PFAS challenge. Establishing water quality standards for PFAS compounds in freshwater PWS designated waters is an important strategy to prevent these chemicals from getting into drinking water supplies.  

Thank you for your attention to this matter. Please contact Greg Prelewicz, Manager, Planning, at 703-289-6318 if you have additional questions or need additional information.