There is little doubt when water contains iron. "Iron water" readily stains plumbing fixtures, porcelain and cooking utensils. When used in the laundry, it soon stains washables with reddish-brown discolorations. An "iron water" also leaves its telltale marks on walls and floors if used in doing home cleaning chores.

Iron water, if not treated, can lead to serious complications in many industrial applications. In fact, there is hardly any wet process work that can be carried on successfully with water that contains iron.

Iron imparts a disagreeable metallic taste to water. Even when water contains small amounts of iron a disagreeable, somewhat astringent quality is apparent. Naturally when iron is present in detectable amounts, it can ruin the flavor of tea, coffee and alcoholic beverages. Further, the combination of soluble iron and certain of the constituents in the beverages gives them an unappetizing, inky black appearance.

In its insoluble forms, iron can form deposits in pressure tanks, pipe lines, water heaters, commodes and in any other equipment where water is used.

Iron problems, either alone or in combination with other troublesome water conditions, are frequent due to the fact that about five percent of the earth's crust is made up of iron. Though not found in a pure state, iron ores are abundant and widely distributed over the earth.

Dissolved concentrations of iron in excess of 60 mg/l are known to exist. Usually, however, no more than 5 mg/l of iron are present in a water supply. Unfortunately, iron in water becomes a real source of trouble to the homemaker when as little as 0.3 mg/l is present, generally considered to be the minimum staining level in homes. For many industrial needs an even more critical tolerance of just 0.1 mg/l is necessary.

Most waters possess hardness minerals in amounts from 3 to 50 gpg (51.3 to 855 mg/l). Unfortunately, where water is extremely hard, the problem is often compounded by the presence of other contaminants such as iron and manganese.

Most people are quite aware that a water containing 15 to 30 grains (256.5 to 513 mg/l) of hardness minerals is definitely hard and difficult to use.

On the other hand, many people will tolerate a 5 grain (85.5 mg/l) water that is very objectionable to anyone accustomed to using completely soft water.

Water collects iron in several ways. Even as it falls through the air, water acquires small amounts of the oxides of iron found in the atmospheric dust. Water, rich in carbon dioxide, readily dissolves iron from the earth's plentiful deposits as it leaches these in its underground flow.