Hard water is found in over 80% of the United States. Hard water is generally not considered a health hazard. Hard water can be problematic in terms of drinking water taste and color. The effects of hard water are more a problem resulting in deposits and scale build up inside pipes and plumbing and on cookware and appliances such as water heaters and dishwashers. |
| So what is Hard Water ? The hardness of a water supply is determined by the content of calcium and magnesium salts. Calcium and magnesium combine with bicarbonates, sulfates, chlorides, and nitrates to form these salts. The standard domestic measurement for hardness is grains per gallon (gpg) as CaCO3 . Water having a hardness content less than 0.6 gpg is considered commercially soft. The calcium and magnesium salts which form hardness are divided into two categories: 1) Temporary Hardness (containing carbonates) 2) Permanent Hardness (containing non-carbonates).
Below find listings of the various combinations of permanent and temporary water hardness along with their chemical formula and some information on each water hardness problem. Temporary Salts that Cause Water Hardness Calcium Carbonate (CaCO3) - Known as limestone, rare in water supplies. Causes alkalinity in water. Calcium Bicarbonate [Ca(HCO3)2] - Forms when water containing CO2 comes in contact with limestone. Also causes alkalinity in water. When heated CO2 is released and the calcium bicarbonate reverts back to calcium carbonate thus forming scale. Magnesium Carbonate (MgCO3) - Known as magnesite with properties similar to calcium carbonate. Magnesium Bicarbonate [Mg(HCO3)2] - Similar to calcium bicarbonate in its properties. Permanent Salts That Cause Water Hardness Calcium Sulfate (CaSO4) - Know as gypsum, used to make plaster of paris. Will precipitate and form scale in boilers when concentrated. Calcium Chloride (CaCl2) - Reacts in boiler water to produce a low pH as follows: CaCl2 + 2HOH ==> Ca(OH)2 + 2HCl Magnesium Sulfate (MgSO4) - Commonly known as epsom salts, may have laxative effect if great enough quantity is in the water. Magnesium Chloride (MgCl2) - Similar in properties to calcium chloride. Sodium salts are also found in household water supplies, but they are considered harmless as long as they do not exist in large quantities. The US EPA currently has no national policy with respect to the hard water levels or soft water levels of public water supplies. Hard Water TreatmentWater softening systems can remove compensated water hardness up to a practical limit of 100 gpg. If the hardness is above 30 gpg or the sodium to hardness ratio is greater than 33%, then economy salt settings can not be used for hard water treatment. If the water hardness is high, then the sodium levels will be high after softening, and may require that a reverse osmosis system be used for filtering drinking water as an effective hard water treatment and removal solution. Before making any purchase of a system, make sure you have completed a hard water test. We offer simple to use test strips for hard water testing. |