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Hard Water
Studies indicate that 60 percent of homes in the UK are supplied with hard water. Hard water costs you money, causes soap scum and scale, and reduces the efficiency of water-using appliances.
What Is Hard Water?
Hard water contains dissolved calcium and magnesium ions. Commonly referred to as "hardness minerals," dissolved calcium and magnesium can cause numerous problems when present in a water supply.
As water falls from the sky in its various forms, it absorbs carbon dioxide in the air and becomes slightly acidic. Water in this weak acid state reaches and enters the ground. Since it is acidic, it absorbs calcium and magnesium, among other things, from the layers of rock through which it passes. The minerals neutralize the water's acidity but also make it hard. Then the water finds its way into larger bodies of water both above and below ground, and eventually into our homes. |
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Water hardness is typically measured in "parts per million," an indication of the quantity of dissolved calcium and magnesium the water contains. In amounts as small as one part per million, water is classified as "hard" to a certain degree. Most homes use water that is considerably harder. While many families choose to soften their water by removing the calcium and magnesium with home water treatment equipment, many don't even realise they have hard water. |
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How to Recognise Hard Water
Probably the most recognisable symptoms of hard water are soap scum in the bath tub and shower, and hard water spots on taps and fixtures. According to a study from The Ohio State University, the average person cleaning a home spends more than six hours a month cleaning tap water spots, streaks and scum alone. Hardness minerals react with soaps and detergents to form an insoluble, sticky residue that's difficult to rinse from bath tubs, sinks, taps and fixtures. The same soap residue is often left on hair, skin and clothing, too. Although not highly visible in these instances, it can cause your skin to dry and itch, and clothing to fade and wear prematurely.
Hard water causes other problems, as well. Over time, scale formed from continuous contact with dissolved minerals in water can collect inside plumbing and on the internal parts of water-using appliances. Service calls to plumbers and repair persons may become necessary as water pressure drops and mechanical parts stop working.
Hard water scale can also coat the inside of a water heater and drastically reduce its heating efficiency. Greater fuel consumption and higher utility bills result when the appliance has to heat water through a layer of rock. According to a study commissioned by the Water Quality Research Council and conducted at New Mexico State University, water heaters work 22-30 percent less efficiently with hard water, driving up utility bills unnecessarily. |
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What is Soft Water?
Soft water is essentially free of dissolved calcium or magnesium. A small percentage of homes are supplied with naturally soft water. But since naturally soft water usually has not been neutralised by passing through mineral layers in the ground, it can be quite corrosive. Softening water mechanically, such as with a home water softener, does not make it corrosive, however. Since calcium and magnesium are not present in soft water, no adverse reaction with soaps and detergents occurs.
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The result is the virtual elimination of soap scum and the corresponding reduction in time spent cleaning. Hair and skin can "breathe" more readily. And the School of Consumer & Family Sciences at Purdue University conducted a study which proved that the life of clothing and household textiles was prolonged up to 15 percent when they were washed in conditioned water.
Soap usage can be dramatically reduced with soft water. Since the water is already soft, the cleaning agents have no hardness minerals to react with and overcome and lather more readily and work more effectively. In fact, a large proportion of the ingredients in most soaps and detergents consist of chemical "water softeners" added to prevent the reaction between the detergent and the hardness minerals present in most water (the reaction that forms a sticky residue or soap curd). Since such chemicals are not necessary for cleaning with soft water, less soap is required. Soft water households experience considerable savings on laundry detergent, dishwashing detergent, bath soap, hand soap, shampoo and many other cleaning products.
Since soft water contains no scale forming minerals, it leaves the inside of plumbing and water-using appliances free of solidified rock. Appliances operate more efficiently and last longer when using soft water.
How Water Is Softened
The most common method used for softening water is ion exchange, where the dissolved calcium and magnesium ions are exchanged for sodium (commonly referred to as regenerant) ions. Sodium does not cause the problems that are associated with calcium and magnesium. The process is the basis for most water softening equipment on the market today.
Water enters a water softener where it comes in contact with a bed of tiny beads that hold sodium chloride ions. Since the beads are chemically more attracted to calcium and magnesium ions, ion exchange occurs. The calcium and magnesium ions "stick" to the surface of the beads, dislodging the sodium. After the beads are completely exhausted (i.e. covered with calcium and magnesium), a solution is introduced to the system to wash away the calcium and magnesium, and replace the sodium (a process known as regeneration). After the extra solution is rinsed from the resin bed, the entire ion exchange cycle begins again. |
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The following systems are among the most common types of water softeners available:
Manually Operated Water Softeners
Require all functions be performed manually and must be monitored to ensure proper operation. The amount of time and maintenance required to operate these units, as well as their low efficiency ratings, explain why so few are sold today.
Automatic Water Softeners
Perform all functions automatically, but usually rely on an electric timer that initiates regeneration at preset intervals (usually every other day at 3:00 am), no matter how much of the system's capacity has been used. Regeneration can occur too often and decrease efficiency, or not often enough and allow hard water into the home. Since these units typically employ only a single softening tank, only hard water is available to the home when they regenerate. |
Demand-Initiated Regeneration (DIR) Water Softeners
Measure water usage and regenerate only when the system has been used to capacity for optimum efficiency. Single tank DIR systems are typically not as efficient as systems that employ two resin tanks. In single tank units, if regeneration is necessary at a time of the day when soft water may be needed, they must wait until a more appropriate time to regenerate so hard water isn't introduced into the home. To do so, single tank DIR units must employ a reserve capacity of softening resin to make it through the rest of the day. If the reserve isn't enough, the home will be forced to use hard water until the system regenerates. If the reserve is too large, the system won't be used to capacity but regeneration will occur anyway, wasting water and regenerant.
Because twin tank DIR systems automatically switch from tank to tank as they exhaust, they are able to provide a continuous supply of conditioned water, 24 hours a day. Some systems even use soft water to clean themselves to improve efficiency. Countercurrent regeneration also improves the systems' effectiveness. Recommended by most resin manufacturers, countercurrent regeneration regenerates the resin beads more efficiently by reversing the flow through the system during the cleaning process.
Additionally, leading consumer publications including Consumers Digest have recognised that non-electric, twin tank DIR water conditioners have distinct advantages over those that operate with electricity. |
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Water conditioners may be designed to help with other water problems, too, including the reduction of radium, barium and excess iron. In severe cases, however, a separate system may be required for proper performance.
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