The Short Answer Sediment is the catch-all name for undissolved solid particles floating in your water — sand, silt, clay, rust flakes, bits of soil and mineral. It’s the cloudiness you can see, the grit at the bottom of a glass, the tan tint after a storm. On a lab report it shows up as…
The Short Answer Pesticides are the chemicals we spread on purpose to kill things — weeds, insects, fungi — and a fraction of what gets applied to farms, lawns, golf courses, and roadsides ends up dissolved in groundwater, where it can reach a well miles from the nearest field. The word covers a huge range:…
Who this is for: anyone whose water test came back flagging something that doesn’t have its own page here — the less-common contaminants that are real, but rare enough that most people never meet them. This page is an index, not an encyclopedia: for each one, what it is, what removes it, and — where…
The Short Answer If your water looks like weak tea — a yellow or brown tint — and you’ve ruled out rust, you’re almost certainly looking at tannins. They’re natural organic compounds released by decaying vegetation: leaves, bark, roots, peat. The very same family of molecules gives tea its color, red wine its dryness, and…
The Short Answer If your water smells like rotten eggs, you’re smelling hydrogen sulfide — a dissolved gas, produced underground by sulfur bacteria and by sulfur in the rock, and sometimes manufactured right inside your own water heater. Your nose is extraordinarily good at detecting it: you can smell it at concentrations far below anything…
The Short Answer Trace amounts of the medications people take — antibiotics, hormones, antidepressants, painkillers, blood-pressure drugs — do turn up in drinking water. They get there mostly the way you’d guess once you think it through: your body doesn’t absorb all of any drug, so the rest is excreted, goes down the toilet, through…
The Short Answer Microplastics are exactly what they sound like: tiny fragments of plastic, smaller than 5 millimeters, that come both from larger plastic breaking down and from plastic manufactured small to begin with. The smallest, under a micrometer, are called nanoplastics. They are, by now, more or less everywhere — in oceans and rivers,…
The Short Answer VOCs — volatile organic compounds — are a large family of carbon-based industrial chemicals that share two defining traits: they’re synthetic (solvents, fuels, degreasers, dry-cleaning fluid), and they evaporate easily. Names you may know: benzene, from gasoline; TCE and PCE, the solvents behind degreasing shops and dry cleaners; vinyl chloride, from PVC…
The Short Answer These are the viruses we pointed to at the end of the Cryptosporidium profile — the smallest waterborne threats, and in one important way the most counterintuitive. Waterborne viruses like norovirus, rotavirus, and hepatitis A get into water the same way the parasites do: through feces, mostly human, usually by way of…
The Short Answer If you read the Giardia profile, this is the parasite we said was coming — and it’s the harder one. Cryptosporidium (“Crypto” for short) is a microscopic parasite, also spread by swallowing tough little capsules — here called oocysts — that get into water through feces, human or animal. It causes cryptosporidiosis:…