A constant supply of clean soft water is an absolute necessity for the
dyer. Rain water should be collected as much as possible, as this is
the best water to use. The dye house should be by a river or stream,
so that the dyer can wash with a continuous supply. Spring and well
water is, as a rule, hard, and should be avoided. In washing, as well
as in dyeing, hard water is injurious for wool. It ruins the
brilliancy of the colour, and prevents the dyeing of some colours.
Temporary hardness can be overcome by boiling the water (20 to 30
minutes) before using. An old method of purifying water, which is
still used by some silk and wool scourers, is to boil the water with a
little soap, skimming off the surface as it boils. In many cases it is
sufficient to add a little acetic acid to the water.