Well Water in Loudoun County: What to Test and Why

Groundwater in Loudoun County contains manganese, radon, PFOA, and PFOS at levels that exceed EPA health standards, along with elevated chloride and sulfate. These contaminants are present at concentrations serious enough that well owners should test their water and consider treatment options.

Manganese and radon come from the natural rock beneath the county. The underground rock layers in this basin contain minerals that release these elements into groundwater as water moves through them over time. PFOA and PFOS are human-made chemicals that come from past industrial activity, manufacturing, or the breakdown of products like firefighting foam. Chloride and sulfate also accumulate from both natural weathering of rock and human sources like road salt and fertilizers.

Groundwater in this county is moderately hard, driven by calcium and magnesium from the rock below. These minerals dissolve naturally as water travels through the underground layers. Most wells in Loudoun County show this moderate hardness along with the other mineral characteristics described above.

Wells in Loudoun County commonly exceed EPA health standards for PFOS and PFOA, which are industrial chemicals that build up in your body over time and can affect your immune system, liver, and thyroid. Chloride and sulfate at elevated levels can cause digestive issues, especially for infants and people with kidney problems. Manganese and radon also exceed safe levels in many county wells--manganese affects the nervous system, and radon is a radioactive gas that increases lung cancer risk when breathed in over years.

The moderate hardness and iron levels in county wells can leave orange or brown stains on fixtures, laundry, and skin. You might notice a metallic taste in your water or buildup of scale inside pipes and on appliances. Over time, hard water can shorten the life of water heaters and dishwashers by several years.

We recommend testing your well with a comprehensive panel that checks for metals, minerals, and those industrial chemicals--testing is the only way to know what is actually in your water, since every well is different and yours could be higher or lower than the county average. A comprehensive panel typically costs $200 to $400. Treatment options like reverse osmosis, carbon filters, or water softeners can address specific problems once you know what you are dealing with.