Water Hardness

Hardness is measured in grains per gallon (gpg) or parts per million (ppm). Water containing less than 3.5 gpg is considered soft, whereas water with more than 7 grains is considered hard. (See Table 1 for the American Society of Engineers' water hardness classifications.)

Moderately hard, hard, and very hard water contain minerals in sufficient amounts to make water softening a viable opbon. Untreated water makes cleaning more difficult and encourages the deposidng and redeposidng of dirt and mineral compounds onto fabrics. Your local water company can give you informadon on water hardness if you use a municipal water supply. (Note: Hardness may vary after leaving the treatment plant because of corrosive pipes). Approximately 31 percent of North Carolinians use water with hardness greater than 60 ppm, according to the U.S. Geologicai Survey (North Carolina Department of Water Resources, Conservadon and Development). Water hardness tends to occur most often in the central piedmont and coastal areas.

Hard water affects laundering in several ways. Incomplete soil removal is common in hard water. White fabrics may become grayed and dingy. As unremoved soil deposits accumulate, fabrics feel harsh and sdff.

There are three ways to help control water hardness when doing the laundry.

• Use adequate amounts of an appropriate detergent and water as hot as recommended for the fabric.
• Use a packaged water softener - often labeled water condidoner.
• Install a water softening unit.

Detergents In the past, powdered phosphate detergents have been recommended for laundering in hard water because phosphate builders tie up hardness minerals and hold them in solution until they can be rinsed away. Phosphate detergents are not an option in North Carolina. The Clean Detergent Act, of 1987, seeking to reduce the amount of phosphorus in the state's rivers, lakes and sounds, prohibited the use of detergents containing phosphorus (phosphates).

They do not contain phosphates and are effective in removing a number of soils in hard water. These detergents contasn a high concentration of surfactants (surface active agents) for cleaning power and are less sensitive to water hardness.

A sufficient amount of detergent is always important for good cleaning results. Extra detergent may be needed in hard water. There is no set guide for increasing the amount of detergent. You will need to experiment and observe the results.

Good laundry practices - sorting, pretreating, limiting size of laundry loads, and using water as hot as is appropriate also contributes to good cleaning results in hard water.

Packaged Water Softeners. To be most effective, a water conditioner should be added at the beginning of both the wash and the rinse cycles. The conditioner's chemicals tie up the hardness minerals, and allow the detergent to do a good cleaning job.

There are two kinds of water conditioners, precipitating and nonprecipitating. Nonprecipitating types are best for hard water laundering because they remove hardness minerals and hold them in solution. This allows them to be flushed away rather than deposited on the clothes as the water is extracted during spinning and rinsing. Precipitating types combine with hardness minerals to form solid particles that cloud the water and cling to fabrics. Nonprecipitating types of water conditioners are recommended for automatic washers

Mechanical Water Softeners. In general, you can control up to about 15 to 16 grains of water hardness minerals with detergents and packaged water conditioners. If your water contains over 15 to 16 grains of hardness, special softening equipment is needed. You may consider installing a home water softening system. Your county Extension Agent can provide information about various treatment options.

Iron

Fabric staining can occur with iron concentrations of 0.2 to 0.3 parts per million. Iron concentrations in North Carolina private wells vary; however the average iron concentration is 0.76 ppm. Laundry problems caused by high concentrations of iron include yellow, orange, or brown stains or spots, or overall discoloration.

Oxygen-type bleaches should be substituted for chlorine bleaches. They do not react with dissolved iron to form stain-causing precipitates. Their bleaching action is milder, and stain removal ability may be more limited. If used consistently, they are effective in maintaining overall whiteness of fabrics.

Nonprecipitating packaged water softeners or conditioners can be used to control small amounts of iron in the wash water. They should be added to the wash water before adding the laundry to keep the rust from depositing on the garments. The conditioner must be used in both wash and rinse water. Use according to package directions.

If, after using packaged water softeners, you still have rust staining problems, it may be necessary to install water treatment equipment.

Summary

Using adequate amounts of an appropriate detergent, and using a packaged water softener can help control laundry problems in moderately hard and hard water. For very hard water installing a water softening unit may be necessary. Small amounts of iron in the wash water can be controlled with nonprecipitating packaged water softeners. For high concentrations of iron it may be necessary to install water treatment equipment.

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