The Short Answer Giardia is a microscopic parasite — and like the organisms in our bacteria profile, it’s alive, which changes everything about how you find it and how you fix it. It’s the most common intestinal parasite infection in the United States; the CDC estimates it sickens more than a million people a year….
The Short Answer If your water smells faintly like a swimming pool, you’re smelling chlorine — and unlike everything else on this site, it’s there on purpose. Chlorine and its cousin chloramine are disinfectants that water utilities add deliberately, and they are one of the great public-health success stories. They are the reason waterborne diseases…
The Short Answer Here’s the most reassuring answer on the whole site: hard water is not a health problem. It’s water with a lot of dissolved calcium and magnesium — minerals it picked up flowing through limestone — and those minerals aren’t toxic. They’re the same calcium and magnesium your body needs. The EPA doesn’t…
The Short Answer Bacteria are the one water problem on this site that’s alive — and that changes everything about how you find it and how you fix it. Unlike lead, arsenic, or fluoride, which are dissolved chemicals you can’t strain out, bacteria are organisms large enough to filter or kill outright. The fix isn’t…
The Short Answer Iron and manganese are the classic well-water nuisances, and they almost always show up together — they come from the same rock, dissolve under the same conditions, and travel through your aquifer side by side. You usually meet them not through a test but through your laundry and fixtures: iron leaves orange…
The Short Answer Fluoride is unusual among the things in your water, for one reason: in most American tap water, it’s there on purpose. About two-thirds of the US population drinks water with fluoride added by their utility, at a target of 0.7 milligrams per liter, to prevent tooth decay. It also occurs naturally —…
The Short Answer Arsenic is a naturally occurring element that dissolves into groundwater straight out of the rock and soil it sits in. It’s a known human carcinogen, and the unsettling part is that it gives you nothing to go on: it has no taste, no smell, and no color in water, even at levels…
Nitrate is the one contaminant on this site with a clock on it. Most water problems do their damage slowly, over years. Nitrate can harm a bottle-fed infant in a matter of days — which is exactly why the rules treat it differently, and why it’s worth understanding before there’s a baby in the house….
Lead and copper get one page here for the same reason the EPA gives them one rule: they are the same story told in two metals. Neither is usually in the water your utility — or your well — draws and treats. Both are picked up afterward, on the last leg of the journey, where…
PFAS in drinking water is one of those problems you can’t see, taste, or smell — which is exactly what makes it worth understanding before you spend a dollar trying to fix it. PFAS — per- and polyfluoroalkyl substances, commonly called “forever chemicals” — are a class of synthetic compounds found in drinking water across…