Stiff towels, white marks on dark clothes, detergent that will not lather, a musty smell that returns a day after drying. Those four complaints are almost always one problem, and it is not your detergent. Check your city below, or run the bottle test if your city is not listed — then treat the actual cause.
Only cities with published water-hardness reporting are listed. If yours is not here, skip to the home test below — it is more accurate for your house anyway, because supply varies street by street.
Pick a city, or at least one symptom.
The bottle test — two minutes, no kit
This is the test plumbers use when they do not have a meter, and it is accurate enough to tell you which problem you are solving.
Fill a clear bottle one-third with tap water
Any clear plastic or glass bottle with a cap. Use water straight from the tap you wash with.
Add a few drops of plain liquid soap
Plain soap, not detergent and not anything labelled moisturising — additives produce lather even in hard water and will give you a false result.
Cap it and shake hard for ten seconds
Then stand it on a flat surface and look at it against the light.
Read it
Soft water: a thick head of bubbles, clear water underneath. Hard water: few bubbles, water looks cloudy or milky, and a scum film forms on the surface. The less it lathers, the harder it is.
What hard water actually does to your clothes
What actually works
In order of how much difference they make relative to what they cost you:
Run an extra rinse. Free.
The single highest-value change. Most of what makes clothes stiff is material that a second rinse would have carried away.
White vinegar in the softener compartment
100–150ml, in the fabric softener tray, not directly on the clothes. It neutralises mineral deposits. The smell does not survive the rinse.
Use less detergent, not more
Counter-intuitive and correct. Hard water tempts you to add more; the excess cannot rinse away and becomes the residue you are trying to remove.
Descale the machine monthly
An empty hot cycle (60°C or higher) with 500ml of white vinegar in the drum. Then wipe the rubber door seal. In a very hard water city this is the difference of years on the machine's life.
Choose a detergent that fully dissolves
Less undissolved material means less to react with the minerals. This helps, but it is fourth on the list for a reason — the rinse and the dose matter more.
No detergent softens water. What a good one does is dissolve completely and leave less behind to react — genuinely useful, and a smaller effect than an extra rinse cycle costing nothing. If a product claims to solve hard water, it is overclaiming, and that includes ours.
Common questions
Is bore water harder than supply water?
Usually, yes. Groundwater picks up dissolved calcium and magnesium from the rock it passes through, while reservoir and river-fed supply generally carries less. That is the underlying reason cities on reservoir sources tend to report softer water than cities relying on groundwater. If your house is on a bore, assume the harder end of whatever your city reports.
Does boiling water soften it?
Only partly, and not usefully for laundry. Boiling removes temporary hardness by precipitating some carbonates — that is what forms the scale in your kettle — but it does nothing to permanent hardness, and boiling water for every wash is not practical. Treat it as a fact about kettles rather than a laundry technique.
Will a water softener fix it?
A whole-home softener genuinely works and is the only complete fix, but it is an installation with an ongoing salt cost, and for most households the rinse-and-vinegar combination gets the majority of the benefit for almost nothing. Consider a softener if you are in a very hard water city, you are already replacing appliances early, and you plan to stay in the house.
Why does my washing smell musty even when it is clean?
Residue feeds odour-causing bacteria, and hard water increases residue — so the two problems compound, particularly in humid months. Fixing the residue usually fixes the smell. There is a longer piece on musty smell in monsoon that covers drying indoors and cleaning the machine itself.