• Hard water contains invisible minerals that are dissolved in it.

• Elements found in water that possess the property of hardness are calcium and magnesium and are usually present in significant amounts in the form of bicarbonates which are soluble in water. Other minerals often found in hard water, normally in relatively small quantities, include iron, copper, and manganese.

• These minerals create problems when using the water for cleaning , heating, or with many types of industrial processes.

• The most prevalent and common problem with water used for applications other than drinking is that of hardness.

• Water in 85 percent of the United States is so hard it should be softened to be of maximum usefulness in both residential and commercial/industrial applications of cleaning, rinsing, heating, and energy production.

• There are only a few areas where water is sufficiently soft to be satisfactory for most homemaking needs. No natural water supply is completely free of hardness.

• 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.

• Water collects iron in several ways. 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. Frequently when water is drawn from a well, iron is present in water in the dissolved state. Upon exposure to the air, molecular oxygen begins to enter the water and oxidizes the iron as carbon dioxide escapes.

• Water carrying dissolved iron readily stains plumbing fixtures, porcelain, and cooking utensils. When used in the laundry, it stains washables with r eddish-brown discolorations. I ron-bearing water also leaves its telltale marks on walls and floors if used in doing home cleaning chores.

• These examples shows the results of iron staining in the bathroom . Not an eye-appealing sight! The stains are extreme ly hard to remove.

• Iron derived from groundwater delivered via irrigation systems and home watering methods can produce unsightly rust stains on concrete sidewalks and driveways, sides of homes and buildings, or landscaping materials.

• When iron -bearing water is mixed with tea, coffee or alcoholic beverages, the mixture turns black. It can ruin the flavor as well.

• When iron stains are found, the water should be tested to measure the amount and type of iron.

Types of Iron in Water

• Inorganic iron exists in water in two oxidation states, +2, or ferrous, and +3, or ferric :

• Iron in the +3 state is commonly known in water treatment as red water iron: Water containing oxidized, ferric, iron compounds is filled with reddish rust particles that are visible in the water when first drawn from the tap.

• Iron in the +2 state is commonly known in water treatment as clear water iron: Water is clear when first drawn from the tap. However, after coming in contact with the air, the ferrous iron oxidizes to ferric, “rusts”, forming red or reddish-brown particles in the water; a gelatinous precipitate. It is commonly found in well water supplies throughout the United States

• Red water iron causes less of a metallic taste than clear water iron, but the taste of both are objectionable.

• Colloidal iron: Very small particles of oxidized, ferric, iron are suspended in the water (less than 0.1 micron). Typically, they are combined with and bound to other substances. Colloidal iron can form when water comes in contact with iron-bearing rock in the presence of decaying vegetation. It may be present in shallow wells or surface water supplies. It is sel dom found in deep well supplies.

• Iron bacteria are living organisms that feed on iron in the water and on iron in wells, piping and tanks. They build slime in toilet flush tanks and can clog pipes, pumps, water heaters and appliances. This can lead to a decrease in water pressure. Bad tastes and odors in the water supply are often common with the presence of iron bacteria. Larger clumps of iron bacteria can cause discoloration of the water.

• Hydrogen sulfide is a gas present in some waters.

• It has an offensive “rotten egg” odor that is sometimes apparent in concentrations as low as 0.5 mg/L.

• Hydrogen sulfide promotes corrosion due to its activity as a weak acid. Its presence in the air causes silver to tarnish in a matter of seconds.

• High concentrations of hydrogen sulfide gas are both flammable and poisonous. While such concentrations are rare, its presence in drinking water has been known to cause nausea, illness, and in extreme cases, death.

• High concentrations of dissolved hydrogen sulfide can also foul the bed of an ion exchange softener. Its continued presence will lead to lower and lower capacity and may finally necessitate replacement of the resin bed.

• Generally, hydrogen sulfide occurs in concentrations of less than 10 ppm (milligrams per liter). Occasionally, the amount goes as high as 50 to 75 mg/L.

• Hydrogen sulfide is more common to well waters than to surface water supplies.

WATER ODOR AND TASTE

• Odors and tastes may be present in water.

• Tastes are generally classified in four groups—sour, salty, sweet, and bitter.

• In general, tastes can be traced to the high concentration of total minerals in water. There are, however, some tastes due to various algae and industrial wastes

• Odors possess many classifications. There are some 20 of them commonly used, all possessing rather picturesque names. In fact, the names in many cases, are far more pleasant then the odors themselves. To name a few of them—nasturtium, cucumber, geranium, fishy, pigpen, earthy, grassy, and musty. Authorities further classify these odors in terms of their intensity from very faint, faint, distinct and decided, to very strong,

• In general, odors can be traced to living organisms, organic matter and gases in water.

• In many cases, it is difficult to differentiate between tastes and odors. Both the taste buds and olfactory organs work so effectively together that it is hard to determine where one leaves off and the other begins.

• For example: hydrogen sulfide gives water an “awful” taste, yet actually, it is the unpleasant odor of this gas that we detect rather than an unpleasant taste.

• Good quality water should not have any off-taste or odors. If you detect a distinct odor, the water is in need of treatment. Unfortunately, there is little in the way of standard measuring equipment for rating tastes and odors.

Specific Tastes and Odors that May Occur in Water and Their Causes

• Decaying organic matter (musty, mildew, cucumber)

• Living organisms (musty odor, rotten egg)

• Iron, manganese, and the metallic products of corrosion (metallic)

• Industrial waste pollution from substances such as phenol (sweet or medicinal, tar-like)

• Chlorination (swimming pool, bleach odor)

• High mineral concentrations (metallic, salty, bitter taste)

• Dissolved gases (sweet, rotten egg, petroleum odor)

CAUSES OF COLOR IN WATER

The color of the water can offer a clue to the contaminants present. Analyses for specific contaminants are still required to confirm the presence and the concentration of contaminants.

Some contaminants, such as dissolved iron, small organic molecules, and tannins can result in similarly-colored water and a multi-step process of elimination may be needed to identify the contaminant responsible for the color,

The following list shows colors and possible contaminants responsible for these colors.

Copper (dissolved)

Dissolved copper gives water a bright blue tint. When acidic, low pH, water passes through copper pipe, it may dissolve some of the copper on the surface of the pipe.

Ferric Iron

Ferric (Fe3+) iron starts out as dissolved ferrous (Fe2+) iron until it contact oxygen. In a distribution system this often happens when water containing ferrous iron is poured into a glass from a tap. The water takes on a reddish/brownish color and flakes (precipitate) of ferric iron begin to form and settle to the bottom of the glass.

Tannins

Water containing tannins can vary in color from a dark brown, indicating a higher tannin concentration, to a weak yellow, indicating a lower tannin concentration.

Color of water with tannins ranging from a high to low concentration, side view.

Color of water with tannins ranging from a high to low concentration, top view.