Jefferson County, West Virginia: drinking water report. Jefferson County occupies the Eastern Panhandle of West Virginia, bordering Maryland and Virginia,…
Jefferson County occupies the Eastern Panhandle of West Virginia, bordering Maryland and Virginia, with about 57,000 residents. The county draws water from the Potomac River and local springs, with the Jefferson County Public Service District and several smaller systems serving different areas. The karst limestone geology underlying much of the county creates sinkholes and underground channels where water moves quickly – carrying contaminants along with it.
Agricultural runoff is the primary water quality concern in Jefferson County. According to the West Virginia DEP's 2024 water quality assessment, nitrate levels in the Potomac River at the county's intake periodically exceed 5 mg/L – half the MCL – driven by fertilizer application and livestock operations in the watershed. The karst geology accelerates the pathway from field to aquifer.
The former Martinsburg Air National Guard base (now the Eastern West Virginia Regional Airport) used AFFF firefighting foam during training exercises. A 2024 West Virginia DEP investigation detected PFAS in groundwater monitoring wells near the facility at 22 ppt combined PFOS/PFOA. Private well users in the area between Ranson and the airport face the most direct exposure risk.
Karst terrain means contamination can travel long distances underground in unpredictable directions. If you are on a private well in Jefferson County, annual testing for nitrate and bacteria is a baseline minimum, with PFAS testing recommended for wells near the airport area.
Check your water for available data on your system. For agricultural contaminants, reverse osmosis or ion exchange filters are effective at the tap. Our water filter guide covers systems suited to rural well water. Get your detailed report for trend data, and visit our West Virginia page for statewide context.
Drinking water is one exposure route. These federal datasets also cover Jefferson County, WV.
The EPA places Jefferson County, WV in Zone 1 - the EPA's highest-risk category, where the predicted average indoor radon level is above 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
38% of homes in Jefferson County, WV were built before 1980, and 11% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Jefferson County, WV averages 7.3 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide