The story begins in the upper clouds where water exists as almost weightless vapour particles. At this point it is similar to distilled water ­ pure H2O, free of impurities. Under certain conditions, the particles combine and, when sufficiently large, fall to earth as rain, snow, sleet or hail, or may appear as dew or fog. As water in these varied forms sweeps the air, splashes to the ground or seeps into the soil, it picks up mineral, gaseous and bacterial impurities. Seventy percent of the water evaporates into the atmosphere before seeping into the ground.
This cycle of precipitation and evaporation goes on endlessly. Roughly three-fourths of all moisture soon returns skyward after falling to earth. In fact, 70% of it may not even reach the ground before evaporating. Of the water not quickly evaporated about one-third becomes surface run-off, flowing into ponds, lakes and rivers. The other two-thirds seeps into the soil to become part of our groundwater supplies. Once underground, it may travel some distance and for a period of many years before man pumps it to the surface.

Regardless of whether water comes from a surface or underground source, it has ample opportunity to pick up impurities before reaching the taps in your home. Some of these impurities ­ tastes, odours, colour and turbidity are quickly noticed. But even in water that is sparkling clear we cannot see such impurities. We detect them only by their effects. Harmful bacteria, if untreated, may lead to disease. Hardness minerals, if not removed, can produce poor results. For example, clothes take on a dingy appearance, when washed in hard water. Dishes and glassware often lose their sparkle. And hair may become dull, unmanageable and lifeless from the use of hard water with shampoos.

There is a common misconception that water as nature provides it is best of all. Actually, most water for industrial, commercial and household purposes is refined or treated. These improvements on the raw product are necessary to make water safe to drink or satisfactory to use.