Tap water
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2008-07-14T05:54:56Z
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/* Tap water uses */ formatting
[[Image:Wasserhahn.jpg|thumb|right|A water tap]]
'''Tap water''' ('''running water''') is part of indoor [[plumbing]], which became available in the late 19th century and common in the mid-20th century.
The provision of tap water requires a massive infrastructure of [[piping]], [[pump]]s, and [[water purification]] works. 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 per gallon.<ref>[http://www.commondreams.org/views07/0218-05.htm The Real Cost of Bottled Water<!-- Bot generated title -->]</ref>
Experimental attempts have been made to introduce non-potable [[greywater]] or [[rain]]water for these secondary uses{{specify}} in order to reduce enormous environmental and energy costs. In urban [[China]], drinking water can be optionally delivered by a separate tap.
The availability of clean tap water brings major [[public health]] benefits. Usually, the same administration that provides tap water is also responsible for the removal and treatment before
discharge or reclamation of [[wastewater]].
In many areas, chemicals containing [[fluoridation|fluoride]] are added to the tap water in an effort to improve public dental health. This remains a controversial issue in the health, freedoms and rights of the individual. 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]] [[ion]]s 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 scares concerning 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 stick to bottled water instead. An example is the recent discovery of potentially [[hazardous]] [[nitrates]] in the public water supply in [[Phoenix, Arizona|Phoenix]], [[Arizona]].<ref>[http://www.kingmandailyminer.com/main.asp?SectionID=13&SubSectionID=18&ArticleID=14218&TM=50186.25 Denied:1up! Software<!-- Bot generated title -->]</ref>
== Tap water uses ==
{{globalize|section}}
According to a 1999 [[American Water Works Association]] study {{Fact|date=October 2007}} 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 [[quart]]s). Daily indoor per capita water use in a typical single family home is 69.3 [[gallon]]s (260 [[litre]]s), falling into the following categories:
* [[Toilet]]s - 26.7% (18.5 gal.)
* [[Clothes washer|Clothes Washers]] - 21.7% (15 gal.)
* [[Shower]]s - 16.8% (11.6 gal.)
* [[Faucet]]s (including [[drinking water]] at ca. 1%) - 15.7% (10.9 gal.)
* [[Leak]]s - 12.7% (9.5 gal.)
* [[bathing|Baths]] - 1.7% (1.2 gal.)
* [[Dishwasher]]s - 1.4% (1.0 gal.)
* Other indoor domestic uses - 2.2% (1.6 gal.)
Of all water supplied to studied homes annually, for perspective, 42 percent was for indoor purposes and 58 percent for outdoor purposes.
==Potable water supply==
[[Image:WaterPipeLarge.JPG|thumb|right|150px|A large [[water pipe]] being laid by the cities' water company]]
This supply may come from several possible sources.
* [[Water purification|Municipal water supply]]
* [[Water well]]s
* Delivered by truck
* Processed water from creeks, streams, rivers, lakes, rainwater, etc.
Domestic water systems have been evolving since the first thinking man located his home near a running water supply, e.g. a stream or river. The water flow also allowed sending waste water away from his domicile.
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.<ref>''Plumbing: the Arteries of Civilization'', Modern Marvels video series, The History Channel, AAE-42223, A&E Television, 1996</ref>
==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.
==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.
Appliances are devices that use water coupled with an additional source of power. connection to these appliances incorporates a backflow prevention principle of some form -- 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.
==Pipe materials==
In old construction, [[lead]] [[plumbing]] was common. It was generally eclipsed toward the end of the 1800s by galvanized iron [[water pipe]]s which were attached with [[Threaded pipe|threaded pipe fittings]]. Higher durability, and cost, systems were made with [[brass]] pipe and fittings. [[Copper]] with [[Soldering|soldered]] fittings became popular around 1950, though it had been used as early as 1900. Despite being [[Green building|environmentally polluting]], plastic supply pipes have become increasingly common since about 1970, with a variety of materials and fittings employed. [[Building code|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 [[pipe (material)|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, [[valve]]s, 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 sprinkler]]s.
===Copper===
{|class="wikitable" style="font-size:97%; text-align:center;" align="right"
|+Copper Tubing Sizes (CTS) for Plumbing
!rowspan=2| Nominal<br /> size
!rowspan=2| Outside diameter (OD)<br /><small>(inches)</small>
!colspan=3| Inside diameter (ID)<br /><small>(inches)</small>
|-
!Type K
!Type L
!Type M
|-
|3/8 ||1/2 ||0.402 ||0.430 ||0.450
|-
|1/2 ||5/8 ||0.528 ||0.545 ||0.569
|-
|5/8 ||3/4 ||0.652 ||0.668 ||0.690
|-
|3/4 ||7/8 ||0.745 ||0.785 ||0.811
|-
|1 ||1-1/8 ||0.995 ||1.025 ||1.055
|-
|1-¼ ||1-3/8 ||1.245 ||1.265 ||1.291
|-
|1-½ ||1-5/8 ||1.481 ||1.505 ||1.527
|-
|2 ||2-1/8 ||1.959 ||1.985 ||2.009
|-
|2-½ ||2-5/8 ||2.435 ||2.465 ||2.495
|-
|3 ||3-1/8 ||2.907 ||2.945 ||2.981
|-
|}
[[Tubing (material)|Tubing]] made of [[copper]] was introduced in about 1900, but didn't become popular until approximately 1950, depending on local building code adoption. Common wall-thicknesses of copper tubing are "Type K", "Type L" and "Type M";<ref>''Copper Tube Handbook'', the Copper Development Association, New York, USA, 2006</ref> Type "M" are relatively thin-walled and generally suitable for condensate and other drains, but sometimes illegal for pressure applications, depending on local codes. Type "L" has a thicker pipe wall section, and is used in residential and commercial water supply and pressure applications, 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. Types "K" and "L" are generally available in both hard drawn "sticks" and in rolls of soft annealed tubing, 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 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).
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 code]]s 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.
===Plastics===
[[Image:SinkPlumbing.jpg|thumb|150px|right|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), [[polybutlyene]] (PB), and [[polyethylene]] (PE) may be allowed by code for certain uses. Some examples of plastics in water supply systems are:
* [[Polyvinyl chloride|PVC]]/[[Chlorinated polyvinyl chloride|CPVC]] - rigid plastic pipes similar to [[Polyvinyl chloride|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.
* [[Polybutylene terephthalate|PBT]] - flexible (usually gray or blue) 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 [[piping|pipe]], but also many fittings and valves which add considerably to their functionality as well as cost. The [[Piping and plumbing fittings]] and [[Valve]]s 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.<ref>''Uniform Plumbing Code'', IAPMO</ref><ref>''International Plumbing Code'', ICC</ref> Even replacing an existing water heater may require a permit and inspection of the work. 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 drainage venting|plumbing drains and vents]] article discusses the topic further, and introduces [[sewage treatment]].
== Tap water vs bottled water ==
{{globalize|section}}
Tap water is an alternative to bottled water, and is preferred by many Americans because their water wholesalers and water companies claim to provide relatively clean and healthy water to consumers.
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.<ref>[http://www.pacinst.org/topics/water_and_sustainability/bottled_water/index.htm Pacific Institute - Bottled Water<!-- Bot generated title -->]</ref>
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 v bottled water campaign, with the slogan, “Tap Water, the Clear Choice”, in 2007.<ref>[http://www.valleywater.org/tapvbottle/ Tap v Bottled Site]</ref>
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.<ref>http://www.stopcorporateabuse.org/tob/File/Austin_Press_Release_10.10.pdf</ref>
==See also ==
{{portalpar|Water|Drinking water.jpg}}
* [[Drought]]
* [[Fountain]]
* [[Irrigation]]
* [[Rainwater]]
* [[Water supply]]
* [[Water pipe]]
* [[Water cycle]]
==References==
<references />
* [[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
==External links==
* [http://www.valleywater.org/tapvbottle/ Santa Clara Valley Water District's Tap v Bottled Campaign Site]
* [http://www.epa.gov/ebtpages/watedrinkingwater.html US Environmental Protection Agency Drinking water page]
* [http://www.awwa.org/ American Water Works Association] for professionals in water production and distribution and other water fields.
* [http://www.fda.gov/fdac/features/2002/402_h2o.html Bottled Water: Better than the Tap?] - A Food and Drug Administration site, explains different sources & treatment of water in depth and compares them.
* [http://www.emagazine.com/september-october_2003/0903feat1.html ''E the Environmental Magazine'' piece on bottled water] (Oct 2003).
*[http://www.iapmo.org/ the International Association of Plumbing and Mechanical Officials]
*[http://www.iccsafe.org/ the International Code Council]
*[http://www.astm.org/ the American Society for Testing and Materials]
*[http://www.ngwa.org/ the National Ground Water Association]
*[http://www.copper.org/ The Copper Development Association]
*[http://www.elocalplumbers.com/ ELocalPlumbers - The nation's #1 directory of local plumbers]
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[[Category:Water supply]]
[[Category:Water|Quality]]
[[Category:Water pollution]]
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