# Problems guides

> Hard water, iron stains, sulfur smell, sediment and bacteria: how to test for each problem and what actually fixes it. From Water Treatment Pro.

Canonical: https://watertreatmentpro.com/problems/

Last updated: 2026-11-08

## Symptom first, equipment second

Almost every wasted water-treatment purchase starts the same way: a symptom is described to a salesperson, and a system is sold before anyone tests the water. Hardness, iron, sulfur, sediment and bacteria each need a different test and a different fix, and two of them can look identical in the shower.

 |
 | Symptom | Likely cause | Test that proves it | What fixes it

 | White scale on fixtures, soap won't lather | Hardness (calcium, magnesium) | Hardness test, grains per gallon | Ion-exchange softener

 | Orange or brown stains, metallic taste | Iron (ferrous or ferric), manganese | Iron and manganese lab test | Oxidation + filtration; softener only for low iron

 | Rotten-egg smell, worse on hot water | Hydrogen sulfide, or bacteria in the heater | Sulfur test; coliform test | Aeration or catalytic carbon; heater sanitising

 | Cloudy or gritty water | Sediment, turbidity | Turbidity and sediment test | Sediment filter, 5–20 micron

 | Blue-green stains, metallic taste | Low pH, corrosive water | pH and alkalinity | Acid neutraliser

 | Stomach illness after drinking | Coliform bacteria, nitrate | Lab bacteria and nitrate test | Disinfection, UV, RO for nitrate

## Hardness: the one you can measure at home

Hardness is reported in grains per gallon (gpg) or milligrams per litre as calcium carbonate. Under 3 gpg is soft, 3–7 is moderately hard, 7–10 is hard, and above 10 is very hard. A $15 titration kit is accurate enough to size a softener; a strip is accurate enough to decide whether you need one at all.

Municipal suppliers publish hardness in the annual water quality report, but the number at your tap can differ after blending or seasonal source changes. Test at the tap, and test both hot and cold if you have a softener already — a failed unit shows up as hard hot water with soft cold.

## Iron: the reason softeners get blamed

Ferrous iron is dissolved and clear; it oxidises to ferric iron on contact with air and turns brown. A softener can handle small amounts — roughly up to 2–3 ppm in many residential units — but higher iron fouls the resin and the unit stops softening. The fix is oxidation (air, chlorine or ozone) followed by filtration, then softening if hardness is also a problem.

Manganese behaves similarly at lower concentrations and stains black rather than orange. If either is above the softener's limit, the order of equipment changes: iron removal first, softener second.

## Sulfur and bacteria: the health line

Hydrogen sulfide is an odour problem; coliform bacteria are a health problem, and only a lab test separates them. A sulfur smell that appears only on hot water usually means bacteria in the water heater, not in the well — sanitising the heater is the fix, not a new filter. A smell on cold water at every tap points to the supply.

Nitrate has no taste and no smell. It comes from fertiliser, septic systems and manure, and it is the one contaminant where a cheap DIY strip is worth using monthly if you have a private well near agricultural land. Above 10 mg/L as nitrogen, do not drink the water and do not mix formula with it; a lab confirmation and a reverse-osmosis unit at the tap are the minimum response.

Start with the [well water testing guide](/well-water-testing/) if you are on a private supply, and the [hard water symptoms guide](/hard-water-symptoms/) if the complaint is scale rather than stains. The [systems hub](/systems/) explains what each piece of equipment removes; the [cost hub](/cost/) carries the installed prices.

### How often should I test well water?

Once a year for bacteria and nitrate, and every 3–5 years for the full panel (pH, hardness, iron, manganese, arsenic, lead). Test sooner if the water changes colour, taste or smell, or if a neighbour's well tests positive for bacteria.

### Can a softener remove bacteria?

No. A softener is an ion-exchange unit, not a disinfectant, and bacteria can multiply in the resin bed. Bacteria need disinfection and usually a UV unit after filtration.

### Is hard water dangerous?

No — it is a nuisance, not a health risk. The costs are scale in appliances, extra soap and shorter water-heater life, which is why the decision is economic rather than medical.

## Guides in Problems

- [How to Test for Arsenic in Water: Lab and Speciation](https://watertreatmentpro.com/arsenic-in-water-test/)
- [Arsenic in Water Treatment: Media, RO, and Oxidation](https://watertreatmentpro.com/arsenic-in-water-treatment/)
- [Arsenic in Well Water: Treatment Options](https://watertreatmentpro.com/arsenic-in-well-water/)
- [How to Test for Bacteria in Water: Sampling Rules](https://watertreatmentpro.com/bacteria-in-water-test/)
- [Bacteria in Water Treatment: UV, Chlorine, or Both](https://watertreatmentpro.com/bacteria-in-water-treatment/)
- [Bacteria in Well Water: Test, Shock, Retest](https://watertreatmentpro.com/bacteria-in-well-water/)
- [Blue-Green Stains: Corrosive Water, Not Copper Pipes Alone](https://watertreatmentpro.com/blue-green-stains/)
- [Can You Drink Softened Water?](https://watertreatmentpro.com/can-you-drink-softened-water/)
- [Chlorine in Tap Water: How Much and How to Remove It](https://watertreatmentpro.com/chlorine-in-tap-water/)
- [How to test for chlorine in water](https://watertreatmentpro.com/chlorine-in-water-test/)
- [Chlorine in water treatment options](https://watertreatmentpro.com/chlorine-in-water-treatment/)
- [Cloudy Water: Air, Sediment or Hardness](https://watertreatmentpro.com/cloudy-water/)
- [How to Test Cloudy Water: Air, Sediment, or Bacteria](https://watertreatmentpro.com/cloudy-water-test/)
- [Cloudy Water Treatment: Match the Cause Before the Filter](https://watertreatmentpro.com/cloudy-water-treatment/)
- [Filtered Shower Head for Hard Water: Media and Limits](https://watertreatmentpro.com/filtered-shower-head-for-hard-water/)
- [Hard water: causes, signs and treatment](https://watertreatmentpro.com/hard-water/)
- [What Hard Water Does to Appliances](https://watertreatmentpro.com/hard-water-and-appliances/)
- [Hard water and hair: what a softener changes](https://watertreatmentpro.com/hard-water-and-hair/)
- [Hard Water and Skin: What the Evidence Supports](https://watertreatmentpro.com/hard-water-and-skin/)
- [Hard water filter](https://watertreatmentpro.com/hard-water-filter/)
- [Hard Water in an Apartment: Options Without Plumbing](https://watertreatmentpro.com/hard-water-in-apartment/)
- [Hard Water Shampoo: What It Can and Cannot Fix](https://watertreatmentpro.com/hard-water-shampoo/)
- [Hard water softener](https://watertreatmentpro.com/hard-water-softener/)
- [Hard water softening system](https://watertreatmentpro.com/hard-water-softening-system/)
- [Hard water stain remover](https://watertreatmentpro.com/hard-water-stain-remover/)
- [Hard Water Stains: What They Are and Why They Form](https://watertreatmentpro.com/hard-water-stains/)
- [Hard Water Symptoms: What Scale Actually Tells You](https://watertreatmentpro.com/hard-water-symptoms/)
- [Hard Water Test: How to Measure Hardness Correctly](https://watertreatmentpro.com/hard-water-test/)
- [Hard Water Test Kit: Strips, Drops, and Lab Panels](https://watertreatmentpro.com/hard-water-test-kit/)
- [Hard Water Treatment: Every Method Compared](https://watertreatmentpro.com/hard-water-treatment/)
- [HOA rules on softeners and brine discharge](https://watertreatmentpro.com/hoa-rules-water-softener/)
- [How to Get Rid of Hard Water Stains for Good](https://watertreatmentpro.com/how-to-get-rid-of-hard-water-stains/)
- [How to Read a Water Test Report: A Homeowner's Guide](https://watertreatmentpro.com/how-to-read-a-water-test-report/)
- [How to Remove Hard Water Stains From Glass Safely](https://watertreatmentpro.com/how-to-remove-hard-water-stains-from-glass/)
- [How to Treat Hard Water: A Decision Path by Number](https://watertreatmentpro.com/how-to-treat-hard-water/)
- [Hydrogen Sulfide Treatment: Aeration vs Chemical Oxidation](https://watertreatmentpro.com/hydrogen-sulfide-treatment/)
- [Ion Hard Water Shampoo: Chelating on a Budget](https://watertreatmentpro.com/ion-hard-water-shampoo/)
- [Iron Bacteria: The Slime That Clogs Filters](https://watertreatmentpro.com/iron-bacteria-in-well/)
- [How to Test for Iron in Water: Lab vs Field Kits](https://watertreatmentpro.com/iron-in-water-test/)
- [Iron in Water Treatment: Choosing the Right Filter](https://watertreatmentpro.com/iron-in-water-treatment/)
- [Iron in Well Water: Testing, Staining and Treatment](https://watertreatmentpro.com/iron-in-well-water/)
- [Lead in Tap Water: Sources and What Removes It](https://watertreatmentpro.com/lead-in-tap-water/)
- [How to Test for Lead in Water: First Draw vs Flushed](https://watertreatmentpro.com/lead-in-water-test/)
- [Lead in Water Treatment: Filters, RO, and Flushing](https://watertreatmentpro.com/lead-in-water-treatment/)
- [Low Water Pressure: Treatment, Mineral, or Plumbing Causes](https://watertreatmentpro.com/low-water-pressure-causes/)
- [How to Test for Low Water Pressure: Static vs Dynamic](https://watertreatmentpro.com/low-water-pressure-test/)
- [Low Water Pressure Treatment: Fix the Cause First](https://watertreatmentpro.com/low-water-pressure-treatment/)
- [Malibu C Hard Water Shampoo: What the Line Does](https://watertreatmentpro.com/malibu-c-hard-water-shampoo/)
- [Malibu c hard water wellness shampoo](https://watertreatmentpro.com/malibu-c-hard-water-wellness-shampoo/)
- [Malibu Hard Water Treatment: Packets, Process, Cost](https://watertreatmentpro.com/malibu-hard-water-treatment/)
- [Manganese in Water: Black Stains and Health Limits](https://watertreatmentpro.com/manganese-in-water/)
- [How to Test for Manganese in Water: Lab and Field](https://watertreatmentpro.com/manganese-in-water-test/)
- [Manganese in Water Treatment: Filters and Limits](https://watertreatmentpro.com/manganese-in-water-treatment/)
- [How to Test for Nitrate in Water: Kits and Labs](https://watertreatmentpro.com/nitrate-in-water-test/)
- [Nitrate in Water Treatment: What Actually Works](https://watertreatmentpro.com/nitrate-in-water-treatment/)
- [Nitrate in Well Water: The Test That Matters](https://watertreatmentpro.com/nitrate-in-well-water/)
- [PFAS in Drinking Water: What a Home Filter Can Do](https://watertreatmentpro.com/pfas-in-water/)
- [How to test for PFAS in water](https://watertreatmentpro.com/pfas-in-water-test/)
- [PFAS in water treatment options](https://watertreatmentpro.com/pfas-in-water-treatment/)
- [Pink Slime in the Bathroom: What It Is and What Helps](https://watertreatmentpro.com/pink-slime-in-bathroom/)
- [Remove Hard Water Stains: Methods That Work by Surface](https://watertreatmentpro.com/remove-hard-water-stains/)
- [Scale in a tankless heater: prevention and descaling](https://watertreatmentpro.com/scale-in-tankless-heater/)
- [How to Test for Sediment in Water: Turbidity and TSS](https://watertreatmentpro.com/sediment-in-water-test/)
- [Sediment in Water Treatment: Filters and Micron Ratings](https://watertreatmentpro.com/sediment-in-water-treatment/)
- [Sediment in Well Water: Filters and the Real Cause](https://watertreatmentpro.com/sediment-in-well-water/)
- [Shower filter for hard water](https://watertreatmentpro.com/shower-filter-for-hard-water/)
- [Shower Head Filter for Hard Water: What It Does](https://watertreatmentpro.com/shower-head-filter-for-hard-water/)
- [Sodium in softened water: how much, and who should care](https://watertreatmentpro.com/sodium-in-softened-water/)
- [Sulfur Smell in Water: Heater or Well?](https://watertreatmentpro.com/sulfur-smell-in-water/)
- [Sulfur Smell Test: Find the Source Before You Treat](https://watertreatmentpro.com/sulfur-smell-test/)
- [Sulfur Smell Treatment: Options by Concentration](https://watertreatmentpro.com/sulfur-smell-treatment/)
- [Tannins in water: the tea-coloured water problem](https://watertreatmentpro.com/tannins-in-water/)
- [How to Test for Tannins in Water: Color vs Iron](https://watertreatmentpro.com/tannins-in-water-test/)
- [Tannins in Water Treatment: Resin, Carbon, and Oxidation](https://watertreatmentpro.com/tannins-in-water-treatment/)
- [Water pressure and filters: why flow drops](https://watertreatmentpro.com/water-pressure-and-filters/)
- [Reading your municipal water quality report](https://watertreatmentpro.com/water-quality-report-reading/)
- [Water Softeners and Septic Systems: The Brine Question](https://watertreatmentpro.com/water-softener-and-septic-system/)
- [Water Spots on Dishes: Hardness or Detergent?](https://watertreatmentpro.com/water-spots-on-dishes/)
- [Water Well Pressure Switch: Settings and Fixes](https://watertreatmentpro.com/water-well-pressure-switch/)
- [Well pump problems that look like treatment problems](https://watertreatmentpro.com/well-pump-vs-treatment/)
- [Well Water Smells After Rain: What Changed](https://watertreatmentpro.com/well-water-smells-after-rain/)
- [Whole House Water Softener for Hard Water: Sizing Guide](https://watertreatmentpro.com/whole-house-water-softener-for-hard-water/)