Dyeing with hard water: water softeners, distilled water, and spring water

'Hard' water contains minerals such as magnesium or calcium. Drinking it may reduce your risk of heart disease, but it sometimes brings problems in dyeing. The minerals can combine with the sodium carbonate, creating 'soap scum', which could, in the case of exceptionally hard water, cause problems such as spotting in your dyeing. The minerals in the water can also create difficult-to-wash-out complexes with some of the dyes.

Sodium Hexametaphosphate from Jacquard is still called Calgon

Chemical water softeners

Using distilled water is an unnecessary expense, however. The easiest solution is to simply buy a phosphate-containing water softener. This water softener, known as Calgon-T or Metaphos, is a powder composed of the chemical sodium hexametaphosphate. Most dye suppliers can sell you this water softener. (See Sources for Dyeing Supplies). Calgon brand laundry water softener may be substituted only if it is not phosphate-free; the old form of Calgon, also known as Calgon T, was sodium hexametaphosphate, which is ideal, but the phosphate-free liquid version of Calgon, containing polycarboxylate, should not be used in dyeing. Jacquard's Calgon, Dharma's Water Softener, and ProChem's Metaphos are all fine, or you can look specifically for the name sodium hexametaphosphate.

If you have very hard water, you should add water softener to your washing machine when washing out excess fiber reactive dye, as well. Hard water can interfere with dye wash-off.

What about water that's been treated by a water softener in the home?

Household water softener systems replace the minerals in the water with salt, sodium chloride. It should be fine for dyeing. The amount of salt added to your hot water by your water softener is typically too small for there to be any need to take it into account in adjusting recipes. See the manual for your water softener for more information, or call its manufacturer. Alternatively, just use your cold water - usually only the hot water supply is softened - and then use one of the phosphate water softeners mentioned above, as needed.

Alternatives for hard water problems

Areas with "bad" water often have coin-operated water purifying machines available outside of grocery stores, which allow you to fill your own containers with water. This water is usually municipal water which has had the offending substances removed by reverse osmosis or filtrations. It should work just fine for dyeing purposes, but chemical water softeners are easier and probably cheaper.

Spring water often has minerals in it, so it is not a good choice for dyeing. Rainwater is very soft and is ideal.