Water Hardness

Click to download Mrs. Stewart's Home Washing GuideHard water does not clean as effectively as soft water. It is caused by minerals like manganese, calcium and iron and easily recognized by bathtub rings or scaling tea pots. These minerals prevent laundry detergents from working and form a detergent curd that sticks to fabrics. They cause gray and dingy looking clothing and give soft fabrics a stiff and harsh texture.

To determine whether you have hard water, call your city water department and ascertain the number of grains per gallon (gpg) or parts per million (ppm) contained in the water for your area. Hard water contains 7.1-10.5 gpg and 121-180 ppm; very hard water contains more than 10.5 gpg and more than 180 ppm.

Hard water can be dealt with in a number of ways:

  • Use adequate amounts of detergent and water. It is not uncommon to have to use slightly more detergent than directed when washing with hard water.
  • Hard water can be eliminated or softened by mechanical home water softeners. However, some only soften hot water and therefore don’t solve the problem when laundering with cold water. If your water hardness is higher than 15-16 grains, a home water conditioner system should be considered.
  • Packaged water conditioners can be used in the wash. These products prevent minerals from inhibiting the detergent. They should be added to both the wash water and the rinse water. Follow instructions on the Product Label. In general, you can control up to about 15-16 grains of water hardness with packaged water conditioners.

If you are having a problem with curds produced by your powdered detergent reacting with your hard water, try switching to a liquid detergent. To remove curding stains, soak in solution of 1 cup vinegar to 1 gallon of water for 30 minutes. Rinse thoroughly, then launder.

Iron Mineral

Laundry problems caused by high concentrates of iron (more than .2 or .3 parts per million) in water include yellow, orange or brown stains or spots or overall discoloration. Oxygen-type bleaches may be substituted for chlorine bleaches as 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, however if used consistently can help prevent iron staining.

In the event that you need to remove iron stains (rust), consult our Stain Removal Guide.