Diagnose your well water
Start from the symptom. Each page works through the causes that produce it and, more usefully, the observation that tells them apart.
The short answer
Most well water problems announce themselves through one of a handful of symptoms — a colour, a smell, a taste, a stain, or a change in pressure. The same symptom usually has three or four possible causes needing completely different fixes, so the useful question is never “what causes orange water” but “which of these is causing mine”.
Pick your symptom
Quick reference: symptom to likely cause
A starting point, not a diagnosis. Each symptom below has several possible causes and the page for it works through how to tell them apart.
| What you notice | Most likely | Usually needs |
|---|---|---|
| Orange or rusty water, stained laundry | Iron | Softener or iron filter |
| Rotten egg smell | Hydrogen sulfide, or the water heater | Anode rod, or an oxidising filter |
| Blue-green staining | Acidic water dissolving copper pipe | Acid neutraliser |
| Black specks | Manganese, or perished rubber | Oxidising filter, or a new pressure tank |
| Metallic taste | Iron, manganese, copper or zinc | Depends which — the staining tells you |
| Cloudy or milky water | Trapped air, or suspended sediment | Pressure tank, or a sediment filter |
| Sand or grit | Well screen, pump depth, water table | Well inspection, plus filtration |
| Musty or earthy taste | Organic matter or bacteria | Test first — this one can mean contamination |
| Pink slime in the bathroom | Airborne bacteria, not your water | Cleaning and ventilation |
| Low or falling pressure | Switch setting, clogged filter, tank, pump | Check in that order — cheapest first |
How to work through a symptom properly
The single most useful habit with well water is to resist matching a symptom to a product. Almost every symptom on this site has three or four causes that produce identical-looking results and need entirely different fixes — and the expensive mistakes nearly all come from skipping that step.
Orange water is the clearest example. Dissolved iron, oxidised iron, iron bacteria and a rusting pressure tank all produce orange water. One is fixed by a softener, one by a filter, one by chlorination, and one by replacing a tank. A softener bought for the fourth case does nothing at all.
So each page here leads with the differential — the causes, and the specific observation that rules each one in or out. Most of those checks cost nothing and take a few minutes: a glass of water on the counter, a sample from an outside spigot, or noticing whether the smell is on the hot tap only.
No obvious symptom?
Plenty of the things worth knowing about well water are invisible. Nitrate, arsenic and coliform bacteria have no taste, no smell and no colour — you cannot diagnose them by observation, only by testing. That is exactly why annual testing is recommended even when nothing seems wrong.
Already have a test result?
Skip the guesswork. Enter the numbers from your lab report and get each one judged against the published EPA limit, plus the treatment train your water actually calls for, in installation order.