Tap water
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Tap water
A water tap Close-up of tap water Tap water (running water, city water, municipal water, drinkable water, etc.) is a part of indoor plumbing which became available in parts of the developed world during the last quarter of the 19th Century, and which became common during the mid-20th Century. The science of providing of pure water to cities, towns, and villages is a major subfield of civil engineering, just as modern sanitary engineering is also a major subfield of it. The providing of clean tap water in modern societies is a massive system of water purification plants, aqueducts, water wells, above-ground and underground water storage tanks, underground tunnels, piping, and occasionally water pumps, all designed and built by civil engineers and construction companies under the supervision of such engineers. The direct cost of the tap water alone, however, is a small fraction of that of bottled water, which can cost from 240 to 10,000 times as much for the same amount.[1] The availability of clean tap water brings major public health benefits. Usually, the same governmental agency of administration that provides tap water is also responsible for the removal and treatment of wastewater. In many areas, chemicals containing fluoride are added to the tap water in an effort to improve public dental health. In some countries, this remains a controversial issue for some of the population. See water fluoridation controversy. Tap water may contain various types of natural but relatively harmless contaminants such as scaling agents like calcium carbonate in hard water and metal ions such as magnesium and iron, and odoriferous gases such as hydrogen sulfide. Local geological conditions affecting groundwater are determining factors of the presence of these substances in water. Occasionally, there are health concerns regarding the leakage of dangerous biological or chemical contaminating agents into local water supplies when people are advised by public health officials not to drink the water, and drink bottled water instead.
Tap water uses
According to a 1999 American Water Works Association study[citation needed] on residential end uses of water in the United States, Americans drink more than 1 glass of tap water per day (the daily human drinking water requirement being 2-3 U.S. quarts (1.9-2.8 litres)). Daily indoor per capita water use in a typical single family home is 69.3 US gallons (262 l), falling into the following categories: toilets - 26.7% - 18.5 US gallons (70 l) clothes washers - 21.7% - 15 US gallons (57 l) showers - 16.8% - 11.6 US gallons (44 l) faucets (including drinking water at ca. 1%) - 15.7% - 10.9 US gallons (41 l) leaks - 12.7% - 9.5 US gallons (36 l) baths - 1.7% - 1.2 US gallons (4.5 l) dishwashers - 1.4% - 1.0 US gallon (3.8 l) Other indoor domestic uses - 2.2% - 1.6 US gallons (6.1 l) For perspective, out of all the water supplied to dwellings annually 42 percent of it was used for indoor purposes, and 59 percent of it for outdoor purposes, such as for watering lawns, gardens, and trees, and for maintaing water in swimming pools, where inevitably a lot of water evaporates or is otherwise used up. Experimental attempts have been made to introduce non-potable greywater or rainwater for secondary uses such as toilets in order to reduce enormous environmental and energy costs. In urban China, drinking water can be optionally delivered by a separate tap. Potable water supply This supply may come from several possible sources. Delivered by truck Processed water from creeks, streams, rivers, lakes, rainwater, etc. Domestic water systems have been evolving since people first located their homes near a running water supply, e.g., a stream or river. The water flow also allowed sending waste water away from the domiciles. Modern indoor plumbing delivers clean, safe, potable water to each service point in the distribution system. It is imperative that the clean water not be contaminated by the waste water (disposal) side of the process system. Historically, this contamination of drinking water has been the largest killer of humans.[2] [edit] Hot water supply Domestic hot water is provided by means of water heater appliances, or through district heating. The hot water from these units is then piped to the various fixtures and appliances that require hot water, such as lavatories, sinks, bathtubs, showers, washing machines, and dishwashers. [edit] Fixtures and appliances Everything in a building that uses water falls under one of two categories; Fixture or Appliance. As the consumption points above perform their function, most produce waste/sewage components that will require removal by the waste/sewage side of the system. Fixtures are devices that use water without an additional source of power. The minimum is an air gap. See cross connection control & backflow prevention for an overview of backflow prevention methods and devices currently in use, both through the use of mechanical and physical principles. [edit] Pipe materials In old construction, lead plumbing was common. It was generally eclipsed toward the end of the 1800s by galvanized iron water pipes which were attached with threaded pipe fittings. Higher durability, and cost, systems were made with brass pipe and fittings. Copper with soldered fittings became popular around 1950, though it had been used as early as 1900. Plastic supply pipes have become increasingly common since about 1970, with a variety of materials and fittings employed, however plastic water pipes do not keep water as clean as copper and brass piping does. Copper pipe plumbing is bacteriostatic. This means that bacteria can't grow in the copper pipes. Plumbing codes define which materials may be used, and all materials must be proven by ASTM, UL, and/or NFPA testing. Steel Galvanized steel supply pipes are commonly found with interior diameters from 1/2" to 2", though most single family homes' systems won't require any supply pipes larger than 3/4". Pipes have National Pipe Thread (NPT) standard male threads, which connect with female threads on elbows, tees, couplers, valves, and other fittings. Galvanized steel (often known simply as "galv" or "iron" in the plumbing trade) is relatively expensive, difficult to work with due to weight and requirement of a pipe threader, and suffers from a tendency to obstruction due to mineral deposits forming on the inside of the pipe. It remains common for repair of existing "galv" systems and to satisfy building code non-combustibility requirements typically found in hotels, apartment buildings and other commercial applications. It is also extremely durable. Black lacquered steel pipe is the most widely used pipe material for fire sprinklers. Copper Tubing made of copper was introduced in about 1900, but didn't become popular until approximately 1950, depending on local building code adoption.
Sizes Common wall-thicknesses of copper tubing are "Type K", "Type L" and "Type M":[3] Type K has the thickest wall section of the three types of pressure rated tubing and is commonly used for deep underground burial such as under sidewalks and streets, with a suitable corrosion protection coating or continuous polyethylene sleeve as required by code. Type L has a thinner pipe wall section, and is used in residential and commercial water supply and pressure applications. Type M has the thinnest wall section, and is generally suitable for condensate and other drains, but sometimes illegal for pressure applications, depending on local codes. Types K and L are generally available in both hard drawn "sticks" and in rolls of soft annealed tubing, whereas type M is usually only available in hard drawn "sticks". Thin-walled types used to be relatively inexpensive, but since 2002 copper prices have risen considerably due to rising global demand and a stagnant supply. In the plumbing trade the size of copper tubing is measured by its nominal diameter (average inside diameter). Some trades, heating and cooling technicians for instance, use the outside diameter (OD) to designate copper tube sizes. The HVAC tradesman also use this different measurement to try and not confuse water pipe with copper pipe used for the HVAC trade, as pipe used in the Air-conditioning trade uses copper pipe that is made at the factory without processing oils that would be incompatible with the oils used to lubricate the compressors in the AC system. The OD of copper tube is always 1/8th inch larger than its nominal size. Therefore, 1" nominal copper tube and 1-1/8th" inch ACR tube are exactly the same tube with different size designations. The wall thickness of the tube, as mentioned above, never affects the sizing of the tube. Type K 1/2" nominal tube, is the same size as Type L 1/2" nominal tube (5/8" ACR). Lead leaching Generally, copper tubes are soldered directly into copper or brass fittings, although compression, crimp, or flare fittings are also used. Formerly, concerns with copper supply tubes included the lead used in the solder at joints (50% tin and 50% lead). Some studies have shown significant "leaching" of the lead into the potable water stream, particularly after long periods of low usage, followed by peak demand periods. In hard water applications, shortly after installation, the interior of the pipes will be coated with the deposited minerals that had been dissolved in the water, and therefore the vast majority of exposed lead is prevented from entering the potable water. Building codes now require lead-free solder. Building Codes throughout the U.S. require the use of virtually "lead-free" (<.2% lead) solder or filler metals in plumbing fittings and appliances as well. Corrosion Copper water tubes are susceptible to cold water pitting, bad plumbing ground pinholes, and erosion corrosion Bad plumbing ground pinholes
Pinhole leaks occur anytime copper piping is improperly grounded. Typically not found in new homes, pinholing due to bad grounding occurs in homes where the original plumbing has been modified. Homeowners may find a new water filtration device has interrupted the ground when they start seeing water leaks after a recent install. It occurs very rapidly, usually being seen about six months after the ground interruption. Correctly installed appliances will have a copper jumper cable connecting the interrupted pipe sections. Non-copper (i.e., Pex) installs, do not have this problem. The effect is known as galvanic erosion or electrolytic pinholing. It occurs because the water is forced to act as an electrical conduit across the jumpered section, resulting in ionization of materials in the water. When the water conducts the electrical potential back to the copper on the other side of the gap, the ionized minerals bind with the copper creating copper salts. Eventually pin hole leaks form, and where there is one, there are usually more. If you call a plumber out for two pin hole leaks, be sure to examine the grounding. It is very aggressive. Detecting and eliminating bad grounding is relatively straightforward. Detection is accomplished by use of a simple voltmeter set to DC with the leads placed in various places in the plumbing. Typically, a probe on a hot pipe and a probe on a cold pipe will tell you if there is improper grounding. Anything beyond a few millivolts is important, potentials of 200 mV are common. A bad ground will show up best in the area of the gap, as potential disperses as the water runs. Since the bad ground is usually seen near the water source, as filtration and treatment equipment are added, pinhole leaks can occur anywhere downstream. It is usually the cold water pipe, as this is the one that gets the treatment devices. Fixing the problem is a simple matter of either purchasing a copper jump kit, composed of a stranded copper cable at least 5mm in diameter and two clamps for affixing it the plumbing. Simpler fixes are possible by taking a length of electrical wire, stripping it on both ends, and affixing it to both sides of the gap. Thin wire, such as household electrical wire, will cure the ground problem, but if there is a surge from a lightning strike, it may break the thin wire, which is why store bought kits are thicker wire—to survive electrical surges. A similar jumper wire can also be seen crossing gas meters, but for a different reason. Note, if homeowners are experiencing shocks or sparks from plumbing fixtures or pipes, it is more than a bad ground, it is likely an electrical wire bridging to the plumbing, but the result is the same, galvanic corrosion. Pinhole leaks from galvanic corrosion can result in thousands of dollars in plumbing bills, and sometimes necessitating the replacement of the entire affected line. Plastics Plastic piping placed for a sink Plastic pipe is in wide use for domestic water supply and drainage, waste, and vent (DWV) pipe. For example, polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polypropylene (PP), polybutylene (PB), and polyethylene (PE) may be allowed by code for certain uses. Some examples of plastics in water supply systems are: PVC/CPVC - rigid plastic pipes similar to PVC drain pipes but with thicker walls to deal with municipal water pressure, introduced around 1970. PVC should be used for cold water only, or venting. CPVC can be used for hot and cold potable water supply. Connections are made with primers and solvent cements as required by code. PBT - flexible (usually gray or black) plastic pipe which is attached to barbed fittings and secured in place with a copper crimp ring. The primary manufacturer of PBT tubing and fittings was driven into bankruptcy by a class-action lawsuit over failures of this system. However, PB and PBT tubing has returned to the market and codes, typically first for 'exposed locations' such as risers. PEX - cross linked polyethylene system with mechanically joined fittings employing barbs and crimped steel or copper fittings. Polytanks - plastic polyethylene cisterns, underground water tanks, above ground water tanks, are made of linear polyethylene suitable as a potable water storage tank, provided in white, black or green, approved by NSF and made of FDA approved materials. Aqua - known as PEX-Al-PEX, for its PEX/aluminum sandwich - aluminum pipe sandwiched between layers of PEX and connected with brass compression fittings. In 2005, a large number of their fittings were recalled. Fittings and valves Potable water supply systems require not only pipe, but also many fittings and valves which add considerably to their functionality as well as cost. The Piping and plumbing fittings and Valves articles discuss them further. Regulation and compliance Before a water supply system is constructed or modified, the designer and contractor need to consult the local plumbing code and obtain a building permits prior to construction.[4][5] Even replacing an existing water heater may require a permit and inspection of the work. NSF 61 is the U.S. national standard for potable water piping guidelines. National and local fire codes should be integrated in the design phase of the water system too to prevent "failure comply with regulations" notices. Some areas of the United States require on-site water reserves of potable and fire water by law. Waste water The waste water from the various appliances, fixtures, and taps is transferred to the waste and sewage removal system via the sewage drain system. This system consists of larger diameter piping, water traps, and is well vented to prevent toxic gases from entering the living space. The plumbing drains and vents article discusses the topic further, and introduces sewage treatment. Tap water versus bottled water
Bottled water has reduced amounts of copper, lead, and other metal contaminants since it does not run through the plumbing pipes where tap water is exposed to metal corrosion. The levels vary for every household and plumbing system, but usually the minor levels of lead and copper are negligible.[6] In 2007, it was found that some bottled water companies were selling water that was contaminated and less healthy for consumers than tap water. The Natural Resources Defense Council (NRDC) conducted a four year study on bottled water. The results of this study show that one-third of the bottled water tested contained levels of contamination which exceeds allowable limits under either state or bottled water industry standards or guidelines.[7] In a study with 57 bottled water samples and tap water samples, all of the tap water samples had a bacterial content under 3 CFUs/mL and the bottled water samples' bacterial content ranged from 0.01-4900 CFUs/mL(colony-forming unit). Most of the water bottle samples were under 1 CFU/mL, though there were 15 water bottle samples containing 6-4900 CFUs/mL.[8] In another study comparing 25 different bottled waters, most of the samples resulted exceeding the contaminant level set by the U.S. Environmental Protection Agency (EPA) for mercury, thallium, and thorium.[9] Being exposed to these contaminants in high concentration for long periods of time can cause liver and kidney damage, and increase risk for lung and pancreas disease. Many large corporations and some water companies and wholesalers, especially in the California Bay Area are now making a large effort to promote tap water over bottled water. Some of the Bay Area cities that promote tap over bottled water include San Francisco, Emeryville, Santa Clara, and Oakland. The Santa Clara Valley Water District in Santa Clara County launched its tap versus bottled water campaign, with the slogan, "Tap Water, the Clear Choice", in 2007.[10] James Workman, author of the book Heart of Dryness: How the Last Bushmen Can Help Us Endure the Coming Age of Permanent Drought and co-founder of SmartMarkets says that he doesn't believe that "tap water is bad and bottled water is good". Rather he cites differences in quality regulations and standards. "Bottled water is often tap water put through another filter and not held to the same quality regulations as public utility water is."[11] During the 2007 U.S Conference of Mayors, the mayors of San Francisco, Salt Lake City and Minneapolis signed a pledge to promote tap water over bottled water as part of the "Think Outside the Bottle" campaign.[12] Chlorine is a disinfectant which is added to tap water in the United States. Chlorine can leave organic material like trihalomethanes and haloacetic acids in the water. The level of chlorine found is small, 1L of chlorinated water gives 0.2 mg of chlorine, which is too small to cause any health problems.[6] While most U.S. cities have what is considered safe tap water, contaminants ranging from bacteria to heavy metals are present in some tap water and violations of tap water standards have been well-publicized, such as the severe 1993 Cryptosporidium outbreak in Milwaukee, Wisconsin, which led to several deaths and around 400,000 illnesses (see: Milwaukee Cryptosporidium outbreak). The University of Cincinnati recently completed a Tap Water Quality Analysis, funded by PUR, for major US cities.[13] Dissolved gases Tap water can sometimes appear cloudy, and this is often mistaken for a mineral impurity in the water. Cloudy water, also known as white water, is actually caused by air bubbles coming out of solution in the water. Because cold water holds more air than warm water, small bubbles will appear in water with a high dissolved oxygen content that is heated or depressurized, because this reduces how much dissolved gas the water can hold. This condition is completely harmless, and the cloudiness of the water disappears quickly as the gas is released from the water[14]. See also References ^ The Real Cost of Bottled Water ^ Plumbing: the Arteries of Civilization, Modern Marvels video series, The History Channel, AAE-42223, A&E Television, 1996 ^ Copper Tube Handbook, the Copper Development Association, New York, USA, 2006 ^ Uniform Plumbing Code, IAPMO ^ International Plumbing Code, ICC ^ a b Petraccia, L., Liberati, G., Masciullo S.G., Grassi, M. & Fraioli, A.. "Water, mineral waters and health". Clinical Nutrition 25 (3): 377–385. doi:10.1016/j.clnu.2005.10.002. ^ Pacific Institute - Bottled Water ^ Lalumandier, J.A., & Ayers, L.W. (2000). "Fluoride and bacterial content of bottled water vs tap water". Archives of Family Medicine 9: 246–250. http://courses.washington.edu. Retrieved 2009-11-01. ^ Ikem, A., Odueyungbo, S., Egiebor, N.O., & Nyavor, K. (2001). "Chemical quality of bottled waters from three cities in eastern Alabama". The Science of the Total Environment 285 (1-3): 165–175. doi:10.1016/S0048-9697(01)00915-9. ^ [|van der Leun, Justine] (September 2009). "A Closer Look at New Research on Water Safety". AOL Health. http://www.aolhealth.com/healthy-living/pollution-water-effects. Retrieved September 2009. ^ http://www.stopcorporateabuse.org/tob/File/Austin_Press_Release_10.10.pdf ^ "Tap Water Quality Analysis" ^ Massachusetts Water Resource Authority. http://www.mwra.com/04water/2004/whitewater.htm ASTM B75-02 Specification for Seamless Copper Tube ASTM B42-02e1 Standard Specification for Seamless Copper Pipe, Standard Sizes ASTM B88-03 Standard Specification for Seamless Copper Water Tube AWWA Research Foundation, Residential End Uses of Water, ISBN 1-58321-016-4, 1999 External links The Water Information Center - An online resource for public water system basics and water management issues from the National Academy of Sciences. US Environmental Protection Agency Drinking water page U.S. Centers for Disease Control and Prevention (CDC) Healthy Water - Public Water Systems - One-stop resource for information on public water systems supplying tap water including information on drinking water, fluoridation, water testing, water-related diseases and contaminants, etc., plus links to EPA, WHO, and other resources. Bottled Water: Better than the Tap? - A Food and Drug Administration site, explains different sources & treatment of water in depth and compares them. the International Code Council the American Society for Testing and Materials the National Ground Water Association The Copper Development Association 2008 Municipal Water Pricing Report(Canada)
Water Treatment Methods KNS BUILDING & MAINTENANCE There are many commercial ways of treating hard water including water filters, water softeners, electromagnetic water conditioners and reverse osmosis. In this section we will look at the pro's and con's of several of the available methods to treat hard water.
Packaged Water Softeners These are chemicals which help to control water hardness. There are two types, precipitating and non-precipitating. Precipitating water softeners include washing soda and borax. These products form an insoluble precipitate with calcium and magnesium ions. The mineral ions then cannot interfere with cleaning efficiency, but the precipitate makes water cloudy and can build up on surfaces. Precipitating water softeners increase alkalinity of the cleaning solution and this may damage skin and other materials being cleaned. Non-precipitating water softeners use complex phosphates to sequester calcium and magnesium ions. There is no precipitate to form deposits and alkalinity is not increased. If used in enough quantity, non-precipitating water softeners will help dissolve soap curd for a period of time. Mechanical Water Softeners Mechanical water softening units can be permanently installed into the plumbing system to continuously remove calcium and magnesium. Water softeners operate on the ion exchange process. In this process, water passes through a media bed, usually sulfonated polystyrene beads. The beads are supersaturated with sodium. The ion exchange process takes place as hard water passes through the softening material. The hardness minerals attach themselves to the resin beads while sodium on the resin beads is released simultaneously into the water. When the resin becomes saturated with calcium and magnesium, it must be recharged. The recharging is done by passing a salt (brine) solution through the resin. The sodium replaces the calcium and magnesium which are discharged in the waste water. Hard water treated with an ion exchange water softener has sodium added. According to the Water Quality Association (WQA), the ion exchange softening process adds sodium at the rate of about 8 mg/liter for each grain of hardness removed per gallon of water. For example, if the water has a hardness of 10 grains per gallon, it will contain about 80 mg/liter of sodium after being softened in an ion exchange water softener if all hardness minerals are removed. Because of the sodium content of softened water, some individuals may be advised by their physician, not to install water softeners, to soften only hot water or to bypass the water softener with a cold water line to provide unsoftened water for drinking and cooking; usually to a separate faucet at the kitchen sink. Mechanically softened water is not recommended for watering plants, lawns, and gardens due to its sodium content. Go to our REVIEW page to see a comparison of water softeners top Water Filters It may be useful to invest in a water filter for your home to make sure that your drinking water is clean and free from contaminants. There are different forms of water filters available today, all useful as a water softening treatment: Granulated, activated carbon water filters – These are portable filters that are found in water jugs. They are the most simplest type of filter and removes contaminants such as chlorine, large particles and parasites. They are available at most kitchenware stores and are reasonably cheap if you have a low budget. However, they have a short filter life and don’t filter out many chemicals and bacteria. Carbon block, activated carbon water filters – These types of filters are generally built-in to the water supply in your home. These filters are more expensive than granulated types, but they do give better filtration and do not need to be replaced as often. Ceramic carbon water filters – This type of filter is comprised of a ceramic part and a carbon part, this gives it an ability to filter out a broad range of contaminants from the water supply. Some are infused with silver, as this is a good antibiotic and reduces the number of micro-organisms present. These filters are good value for money. They are built-in to the home water supply and need to be replaced about every 12 months in the average household. Reverse osmosis water filters – These filters are often considered the best form of water filtration available today. The water is passed through a semi-permeable membrane, which filters out almost every contaminant. They are more expensive than other types of filters but have reasonably low running costs, effective filtration and can be used to filter water to the whole house. Combination Systems – This filter has become available in recent years and are seen as an alternative to reverse osmosis systems. They have a number of different filters, and each filtration process removes different contaminants. Alkaline Water Machines – This system not only filters your drinking water but it makes it more alkaline. It is a good system for those with environmental illnesses where there is too much acid in the body. It has effective filtration but it can be expensive and it wastes a lot of water during the filtration process. Water filters cost approximately $0.04 (£0.025) / litre to run. Magnetic Water Conditioners Electromagnetic water conditioners are a relatively new invention. The idea is that by passing water through a magnetic field, the calcium and magnesium ion's are altered in such a way that they loose their ability to cause scale. This has a number of benefits; although the water is not technically soft, it has the useful properties of soft water, that is, it won't cause limescale in your pipes thus increasing heating efficiency and lengthening the lifespan of any clothes washed in the conditioned water. Calcium is an important dietary element, so the fact that conditioned water still retains its calcium content is an added benefit. While some people are skeptical this method actually works, we have found one manufacturer who has commisioned a scientific analysis by the University of Bath that concludes that their device does indeed stop the build up of limescale.
Hard Water Problems KNS BUILDING & MAINTENANCE Water described as "hard" means it is high in dissolved minerals, specifically calcium and magnesium. Hard water is not a health risk, but a nuisance because of its tendancy to cause mineral buildup in water pipe and heating systems, and its poor soap and/or detergent performance when compared with soft water. Water is a good solvent and picks up impurities easily. When it combines with carbon dioxide in the air to form very weak carbonic acid, an even better solvent results. As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium and magnesium dissolved in water are the two most common minerals that make water "hard." The degree of hardness becomes greater as the calcium and magnesium content increases. What Can You Do? There are a number of tips you can follow to reduce the effects of hard water in your home, without having to make any major changes: Choose a correct laundry detergent – Some laundry detergents do not produce as many suds in hard water, these are likely to be soap-based products and do not work as well in hard-water as detergent based products. Nowadays, there are washing powders and liquids available for a wide range of water hardness. Make sure you choose the correct detergent for your area; you may also need to use slightly more detergent than the manufacturers recommended amount to compensate for the hard water. In many cases the manufacturer will give specific instructions on how to use the product in hard water areas, look out for these labels on your product. Reduce the temperature of your boiler – As the water temperature increases, the more mineral deposits will appear in your dishwasher, water tank and pipes. By reducing the heat of your boiler to about 55ºC, you will have enough hot water for your shower and you will reduce the amount of mineral build-up in your pipes and tanks. Use rinse agents to remove mineral deposits – There are many rinse agents available to remove mineral deposits from crockery and dishwasher. Alternatively, you can use white vinegar by using the dishwasher dispenser or placing a cup of vinegar on the dishwasher rack. Boil some white vinegar in your kettle as a useful way of removing hard water deposits. Water conditioners or Water Softeners? Traditionally the water treatment market had one main solution to hard water. This solution was water softeners. However, in recent years alternative treatments have become increasingly popular, the most interesting of which is electromagnetic water conditioning. Water Softeners work by ion exchange, so sodium replaces the calcium and/or magnesium in the water. Water Conditioners on the other hand create a magnetic field around your pipework which alters the ions in the water so that they loose their ability to cause scale. In tackling hard water, both methods will reduce limescale. Water Conditioners are significantly less expensive to start with and they have negligible running costs. Water Softeners cost a lot more but have the added effect that they will treat very small amounts of other metals such as Copper, Iron or Zinc.
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