Why do my clothes come out stiff or gray?
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Stiff, gray or dingy laundry is very often a hard water problem, and it is worse when the cleaning agent is soap. Hard water carries dissolved calcium and magnesium; soap reacts with the calcium to form soap scum, which can stay in the fabric, and every load needs more soap or detergent to get clean. The U.S. Geological Survey classes water above 120 milligrams per liter of hardness as hard and above 180 as very hard. Your water utility can tell you where your tap sits. This page helps you match what you see on your clothes to its likely cause, find your hardness, and decide what to change.
What hard water is, and where your tap sits
The USGS: "Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals" [1]. It is reported as milligrams per liter (mg/L) of calcium carbonate, and USGS classes water above 120 mg/L as hard and above 180 mg/L as very hard [1]. The full USGS table, with the soft and moderately hard bands and what builders do at each level, is on builders and chelators.
Some utilities and water-softener sellers report hardness in grains per gallon instead. The USGS page does not give that unit; if your report uses it, ask the utility for the mg/L figure so you can compare it with the USGS classes.
What you see, what it likely means, what to do
| What you see | What it likely means | What to do |
|---|---|---|
| Towels and jeans dry stiff or scratchy | Soap scum or mineral deposits left in the fibers | Find your hardness; if hard, switch from a soap-based mix to a detergent, or add conditioning (below) |
| Whites turning gray or dingy over weeks | Soil and scum redeposited on the fabric; hard water means "more soap or detergent is needed to get things clean" [1] | Check the dose against your hardness; one stain source suggests a long hot soak with "extra detergent and a water conditioner" for yellowing and dinginess [2] |
| A white film or residue on dark clothes | Undissolved powder or scum | Dissolve powders first; see streaks, clogs and film for the same problem in sprays |
| Orange or rust spots on whites | Iron in the water, sometimes made worse by bleach | "Never use chlorine bleach on rust stain or in water with large amounts of iron" [2]; see removing stains |
| Lots of suds, or a SUDS error, in a front loader | Often the opposite problem: soft water, or too much product. LG: "Soft water can also cause detergents to over-suds" [3] | Use less; LG's manual says "Use less detergent for soft water" [4] |
| Clothes wearing out faster than you expect | USGS: "Hard water can even shorten the life of fabrics and clothes" [1] | Address hardness before blaming the fabric |
The second, fourth and fifth rows show something worth knowing: hard and soft water push in opposite directions. In hard water you tend to need more product; in soft water you need less. Dosing by the bottle's average can be wrong at either end.
Why soap suffers more than detergent
The USGS puts it simply: "In hard water, soap reacts with the calcium (which is relatively high in hard water) to form 'soap scum'" [1]. True soap is a salt of fatty acids; calcium swaps in and makes a version that does not dissolve. Store laundry detergents are built on synthetic surfactants instead, usually with builders added. The homemade powders and liquids built on a bar of laundry soap, such as the UF/IFAS recipes on homemade laundry detergent, are the ones most exposed to this.
Finding your hardness
- Ask your water utility. USGS says local hardness information "should be provided by the local health agency or local water utility" [1]. Many utilities publish it in their annual water quality report.
- If you are on a private well, the utility route does not apply. USGS also names water-softening companies as a source [1]; a lab test through your county or state is another. Neither USGS nor any other source read for this page sets out a home testing method.
- Test strips for hardness are sold for home use. No source read for this page evaluates how accurate they are, so treat a strip result as a rough reading and prefer the utility's figure when you can get it.
- Write the number down with its unit and date. Hardness can change if your utility changes its source.
What builders do, and which ones you already have
A builder is an ingredient that ties up or removes the calcium and magnesium so the soap or detergent can work. The full chemistry, with named builders and chelators, is on builders and chelators. At home the choices are:
- Washing soda (sodium carbonate). The builder in the UF/IFAS recipes [5]. It is strongly alkaline; its hazards and the surfaces it marks are on washing soda.
- Borax (sodium tetraborate). Also in the UF/IFAS recipes [5]. Its hazard classification differs between the EU and the US; borax sets out both.
- Sodium citrate and similar conditioners. Common in commercial detergents. No extension recipe found uses them at home, so no amount is given here.
- A water softener for the house. It removes hardness before the water reaches the washer. Sizing and cost are outside the scope of this page.
None of the sources read gives a dose of extra washing soda or borax to add for a given hardness. Do not improvise one into a recipe and then sell it; if you are only adjusting your own wash, change one thing at a time and keep notes on hardness, dose and result.
When hard water is not the cause
Hard water is the cause the sources read for this page explain, but it is not the only possible one. A stain source credited to Utah State University Extension lists fabric softener spots, which it says to treat by rubbing with bar soap and to prevent by diluting the softener [2]. If your hardness is in the soft range and the problem persists, check your dose against the product's directions and your softener use next; vinegar and other fabric softener alternatives covers the softener side.
Matching your detergent to your water
Once you know your hardness, the decision is mostly about the cleaning agent. If it is hard or very hard, a soap-based recipe will struggle, and homemade laundry detergent explains what is in the published mixes so you can judge. If you wash in a front loader, read homemade detergent in HE washers as well.
References
- U.S. Geological Survey, Water Science School, *Hardness of Water*, page dated August 24, 2026. https://www.usgs.gov/water-science-school/science/hardness-water
- Michigan Department of Health and Human Services, Foster Youth in Transition, *Tips for Getting Stains Out of Your Laundry* (credits Utah State University Extension), undated, read October 2026. https://www.michigan.gov/fyit/housing/tips-for-getting-stains-out-of-your-laundry
- LG Electronics USA, *Too Many Suds in Washing Machine*, LG USA Support help library, May 28, 2026. https://www.lg.com/us/support/help-library/too-many-suds-in-washing-machine--1337715937395
- LG Electronics, *Owner's Manual, WM3997HWA Washing Machine*, "Using Detergent/Fabric Softener" (page 20), read October 2026 in the copy reproduced by ManualsLib (no LG-hosted copy of this manual was found). https://www.manualslib.mx/manual/785300/Lg-Wm3997Hwa.html?page=20
- University of Florida IFAS Extension (Amanda Griffin and Randall A. Cantrell), *Homemade Household Cleaners*, FCS3319, Release Date October 7, 2025. https://ask.ifas.ufl.edu/publication/FY1449
