Private well water, told straight.
Aquifer by aquifer, contaminant by contaminant — what's actually in the water coming out of your tap, and what to do about it.
Roughly 43 million Americans drink water from a private well. Unlike municipal water, nobody tests it for you. Nobody tells you what's in it. Nobody is legally required to warn you when something changes. This site is an attempt to close that gap — organized the way groundwater actually works, not the way state lines are drawn.
Start with your aquifer
If you're on a well, the aquifer underneath you determines almost everything about your water — how much of it you get, how hard it is, what it tastes like, what it might be hiding. Aquifers cross state lines; the same hydrogeologic unit can stretch from Texas to South Dakota.
The principal drinking-water source for nearly all of Florida, southern Georgia, and parts of Alabama and South Carolina — about 10 millio…
Granite, granitic gneiss, and metamorphic bedrock across northern New England carry uranium-bearing minerals that weather into a notoriously…
The largest aquifer in the United States and the source of about 30% of US irrigation. Being drawn down at roughly six times the rate it rec…
Four-layer bedrock aquifer system under Colorado's Front Range, supporting hundreds of thousands of private wells. Being drawn down faster t…
Know what to test for
Every aquifer has a characteristic set of concerns. Some are health hazards; some are nuisances; some will destroy your plumbing. The right test panel depends on what's actually likely to be there.
Naturally occurring metalloid that contaminates groundwater across much of the US, especially the West and parts of New England. Causes canc…
Radioactive gas that dissolves in groundwater from uranium-bearing rock. Enters your home through every tap. Significant cause of lung cance…
Agricultural fertilizer and septic-derived contamination of shallow groundwater. The dominant rural well concern in irrigated farm country. …
The most common nuisance contaminants in private wells: rust stains, black stains, metallic taste. Iron is genuinely cosmetic. Manganese is …
Per- and polyfluoroalkyl substances. Synthetic chemicals invented in the 1940s, used in firefighting foam, non-stick coatings, water-repelle…
Heavy metal that dissolves into groundwater from uraniferous rock — granite, certain sandstones, weathered volcanic terrain. Causes kidney…
About this site
We pull from USGS aquifer monitoring, EPA water quality data, state geological surveys, and the scientific literature to build pages that answer one question: what's in my well water, and what do I do about it? No generic copy. No padded content. Sourced, specific, updated when the evidence changes.