Tap water - AbsoluteAstronomy.com

Tap water is a principal component of "indoor plumbing

Plumbing

Plumbing is the system of pipes and drains installed in a building for the distribution of potable drinking water and the removal of waterborne wastes, and the skilled trade of working with pipes, tubing and plumbing fixtures in such systems. A plumber is someone who installs or repairs piping...

", which became available in urban area

Urban area

An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...

s of the developed world during the last quarter of the 19th century, and common during the mid-20th century. The application of technologies involved in providing clean or "potable" water to homes, businesses and public buildings is a major subfield of sanitary engineering

Sanitary engineering

Sanitary engineering is the application of engineering methods to improve sanitation of human communities, primarily by providing the removal and disposal of human waste, and in addition to the supply of safe potable water. Initially in the mid 19th century, the discipline concentrated on the...

Background

The availability of tap water has major public health

Public health

Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...

benefits, since it typically vastly reduces the risk to the public of contracting water-borne diseases. Providing tap water to large urban or suburban populations requires a complex and carefully designed system of collection, storage, treatment

Water purification

Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...

and distribution, and is commonly the responsibility of a government agency, often the same agency responsible for the removal and treatment of wastewater

Wastewater

Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...

.

Specific chemical compounds are often added to tap water during the treatment process to adjust the pH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

or remove contaminants, as well as chlorine

Chlorine

Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

to kill biological toxins. Local geological conditions affecting groundwater

Groundwater

Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...

are determining factors for the presence of various metal ion

Ion

An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s, often rendering the water "soft" or "hard

Hard water

Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...

".

Tap water remains susceptible to biological or chemical contamination. In the event of contamination deemed dangerous to public health, government officials typically issue an advisory regarding water consumption. In the case of biological contamination, residents are usually advised to boil their water before consumption or to use bottled water as an alternative. In the case of chemical contamination, residents may be advised to refrain from consuming tap water entirely until the matter is resolved.

In many areas a compound of fluoride

Fluoride

Fluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...

is added to tap water in an effort to improve dental health among the public. In some communities "fluoridation

Water fluoridation

Water fluoridation is the controlled addition of fluoride to a public water supply to reduce tooth decay. Fluoridated water has fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride...

" remains a controversial issue. (See water fluoridation controversy

Water fluoridation controversy

The water fluoridation controversy arises from moral, ethical, and safety concerns regarding the fluoridation of public water supplies. The controversy occurs mainly in English-speaking countries, as Continental Europe does not practice water fluoridation...

Potable water supply

This supply may come from several possible sources.

Municipal water supply
Water purification
Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...
Water well
Water well
A water well is an excavation or structure created in the ground by digging, driving, boring or drilling to access groundwater in underground aquifers. The well water is drawn by an electric submersible pump, a trash pump, a vertical turbine pump, a handpump or a mechanical pump...

s
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.

Hot water supply

Domestic hot water is provided by means of water heater appliances, or through district heating

District heating

District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water 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. 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.

Fixtures are devices that use water without an additional source of power.

Pipe materials

The earliest known evidence of drain tile being used for plumbing was found in Mesopotamia and is estimated to have been made around 3000 BC. The tiles were made from clay mixed with short lengths of straw. Both brass and copper pipes have been found in Egypt believed to have been made close to 2500 BC. The Romans made extensive use of lead pipe by joining sheets of lead into piping to carry their water supply and waste. During the Dark Ages following the fall of the Roman Empire, plumbing development virtually ceased for centuries except for isolated cases of plumbing installed in palaces and castles. In the 13th century, blacksmiths formed sheets of iron and lap welded the seam to create iron pipe. Though it is unclear as to when galvanized iron pipe was first used, a French chemist named Melouin is credited with developing the process in 1742. The earliest known use for cast iron pipe is for the water supply to a fountain in Langensalza,Germany, built around 1560. In 1819 the first cast iron pipe constructed in the US, was manufactured in Weymouth, New Jersey. Before that time, cast iron pipe and fittings had to be imported from Europe. It was not until the 1960s that the hubless cast iron pipe was brought to the U.S. from Europe by way of Canada. During the early 1900s, heavy-walled copper joined with threaded fittings was in use, but limited to public buildings because of its high cost. However, during the 1930s light-gauge Copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

tube and fittings were developed which made copper economically feasible and increased its popularity. Polyvinyl Chloride(PVC) was produced experimentally in the 19th century but did not become practical to manufacture until 1926, when Waldo Semon of BF Goodrich Co. developed a method to plasticize PVC, making it easier to process. PVC pipe began to be manufactured in the 1940s and was in wide use during the DWV reconstruction of Germany and Japan following WWII. In the 1950s, plastics manufacturers in Western Europe and Japan began producing acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene is a common thermoplastic. Its melting point is approximately 105 °C ....

(ABS) pipe. The methods for producing cross-linked polyethylene (PEX) was also developed in the 1950s. Plastic supply pipes have become increasingly common, 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

Building code

A building code, or building control, is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the...

define which materials may be used, and all materials must be proven by ASTM, UL

Underwriters Laboratories

Underwriters Laboratories Inc. is an independent product safety certification organization. Established in 1894, the company has its headquarters in Northbrook, Illinois. UL develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing...

, and/or NFPA

National Fire Protection Association

The National Fire Protection Association is a United States trade association that creates and maintains private, copywrited, standards and codes for usage and adoption by local governments...

testing.

Steel

Galvanized steel potable water supply and distribution pipes

Pipe (material)

A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...

are commonly found with nominal diameters from 3/8" to 2". It is rarely used today for new construction residential plumbing. Steel pipe has National Pipe Thread

National pipe thread

National Pipe Thread Tapered Thread is a U.S. standard for tapered threads used on threaded pipes and fittings. The taper rate for all NPT threads is measured by the change of diameter over distance. The angle between the taper and the center axis of the pipe is 1° 47′ 24″...

(NPT) standard tapered male threads, which connect with female tapered threads on elbows, tees, couplers, valve

Valve

A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

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. It remains in common use for repair of existing "galv" systems and to satisfy building code

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

Fire sprinkler

A fire sprinkler system is an active fire protection measure, consisting of a water supply system, providing adequate pressure and flowrate to a water distribution piping system, onto which fire sprinklers are connected...

s and natural gas.

Most single family homes' systems typically won't require supply piping larger than 3/4". In addition to expense, another downside is it suffers from a tendency to become obstructed due to internal rusting and mineral deposits forming on the inside of the pipe over time after the internal galvanizing zinc coating has degraded. In potable water distribution service, galvanized steel pipe has a service life of about 30 to 50 years, although it is not uncommon for it to be less in geographic areas with corrosive water contaminants.

Copper

See also Copper tubing

Copper Tubing Sizes (CTS) for Plumbing
Nominal size	Outside diameter (OD) [in (mm)]	Inside diameter (ID) [in (mm)]
Nominal size	Outside diameter (OD) [in (mm)]	Type K	Type L	Type M
	1/2 in	0.402 (10.211 mm)	0.43 (10.922 mm)	0.45 (11.43 mm)
	5/8 in	0.528 (13.411 mm)	0.545 (13.843 mm)	0.569 (14.453 mm)
	3/4 in	0.652 (16.561 mm)	0.668 (16.967 mm)	0.69 (17.526 mm)
	7/8 in	0.745 (18.923 mm)	0.785 (19.939 mm)	0.811 (20.599 mm)
1	1+1/8 in	0.995 (25.273 mm)	1.025 (26.035 mm)	1.055 (26.797 mm)
1	1+3/8 in	1.245 (31.623 mm)	1.265 (32.131 mm)	1.291 (32.791 mm)
1	1+5/8 in	1.481 (37.617 mm)	1.505 (38.227 mm)	1.527 (38.786 mm)
2	2+1/8 in	1.959 (49.759 mm)	1.985 (50.419 mm)	2.009 (51.029 mm)
2	2+5/8 in	2.435 (61.849 mm)	2.465 (62.611 mm)	2.495 (63.373 mm)
3	3+1/8 in	2.907 (73.838 mm)	2.945 (74.803 mm)	2.981 (75.717 mm)

Sizes

Common wall-thicknesses of copper tubing in the USA are "Type K", "Type L" and "Type M":

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".

In the plumbing trade the size of copper tubing is measured by its nominal diameter (average inside diameter). Some American 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 th inch larger than its nominal size. Therefore, 1 inch nominal copper tube and th 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 inch nominal tube, is the same size as Type L inch nominal tube ( inch ACR).

Common wall-thicknesses in Europe are "Type X", "Type Y" and "Type Z", defined by the EN

European Committee for Standardization

The European Committee for Standardization or Comité Européen de Normalisation , is a non-profit organisation whose mission is to foster the European economy in global trading, the welfare of European citizens and the environment by providing an efficient infrastructure to interested parties for...

1057 standard.

Type X is the most common, and is used in above groundservices including drinking water supply, hot and cold water systems, sanitation, central heating and other general purpose applications.

Type Y is a thicker walled pipe, used for underground works and heavy duty requirements including hot and cold water supply, gas reticulation, sanitary plumbing, heating and general engineering.

Type Z is a thinner walled pipe, also used for above groundservices including drinking water supply, hot and cold water systems, sanitation, central heating and other general purpose applications.

In the plumbing trade the size of copper tubing is measured by its outside diameter in millimetres. Common sizes are 15 mm and 22 mm.

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.

Lead leaching

Generally, copper tubes are soldered directly into copper or brass fittings, although compression

Compression fitting

Compression fittings are used in plumbing and electrical conduit systems to join two tubes or thin-walled pipes together. In instances where two pipes made of dissimilar materials are to be joined , the fittings will also be made of one or more compatible materials appropriate for the connection...

, crimp, or flare

Flare fitting

Flare fittings are a type of compression fitting used with metal tubing, usually soft steel and ductile copper, though other materials are also used. Tube flaring is considered to be a type of forging operation, and is usually a cold working procedure. During assembly, a flare nut is...

fittings are also used. Formerly, concerns with copper supply tubes included the lead used in the solder

Solder

Solder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece.Soft solder is what is most often thought of when solder or soldering are mentioned and it typically has a melting range of . It is commonly used in electronics and...

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

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

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.

Corrosion

Copper water tubes are susceptible to: cold water pitting caused by contamination of the pipe interior typically with soldering flux; erosion corrosion

Erosion corrosion of copper water tubes

Erosion corrosion, also known as impingement damage, is the combined effect of corrosion and erosion caused by rapid flowing turbulent water. It is probably the second most common cause of copper tube failures behind Type 1 pitting which is also known as Cold Water Pitting of Copper Tube.-Copper...

caused by high speed or turbulent flow; and stray current corrosion, caused by poor electrical wiring technique, such as improper grounding and bonding.

Pin holes due to poor plumbing electrical grounding and/or bonding

Pin-hole leaks can occur anytime copper piping is improperly grounded and/or bonded; nonmetal piping, such as Pex or PVC, does not suffer from this problem. The phenomenon is known technically as stray current corrosion or electrolytic pitting. Pin-holing due to poor grounding or poor bonding occurs typically in homes where the original plumbing has been modified; homeowners may find a new plastic water filtration device or plastic repair union has interrupted the water pipe's electrical continuity to ground when they start seeing pinhole water leaks after a recent install. Damage occurs rapidly, usually being seen about six months after the ground interruption. Correctly installed plumbing appliances will have a copper bonding jumper

Bonding jumper

A bonding jumper is a reliable conductor to ensure the required electrical conductivity between metal raceways required to be electrically connected.-Components:...

cable connecting the interrupted pipe sections. Pinhole leaks from stray current corrosion can result in thousands of dollars in plumbing bills, and sometimes necessitating the replacement of the entire affected line. The cause is an electrical problem, not a plumbing problem; once the plumbing damage is repaired, an electrician should be consulted to evaluate the grounding and bonding of the entire plumbing system.

The difference between a ground and a bond is subtle. See Ground, for a complete description.

Stray current corrosion occurs because: 1) the piping system is connected accidentally or intentionally to a DC voltage source; 2) the piping does not have metal-to-metal electrical continuity; 3) if the voltage source is AC, one or more naturally occurring minerals coating the pipe interior act as a rectifier, converting AC current to DC . The DC voltage forces the water within the piping to act as an electrical conductor (an electrolyte). Electric current leaves the copper pipe, moves though the water across the nonconductive section (the plastic filter housing in the example above), and reenters the pipe on the opposite side. Pitting occurs at the electrically negative side (the cathode), which may be upstream or downstream with respect to the water flow direction. Pitting occurs because the electrical voltage ionizes the pipe's interior copper metal, which reacts chemically with dissolved minerals in the water creating copper salts; these copper salts are soluble in water and wash away. Pits eventually grow and consolidate to form pin holes. Where there is one, there are almost certainly more. A complete discussion of stray current corrosion can be found in chapter 11, section 11.4.3, of Handbook of Corrosion Engineering, by Pierre Roberge.

Detecting and eliminating poor bonding 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 missing bond will show up best in the area of the gap, as potential disperses as the water runs. Since the missing bond 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.

Correcting the problem is a simple matter of either purchasing a copper bonding jumper kit, composed of copper cable at least #6 AWG in diameter and two bronze ground clamps for affixing it the plumbing. See NFPA 70, the U.S. National Electrical Code Handbook (NEC), section on bonding and ground for details on selecting the correct bonding conductor wire size.

A similar bonding 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 missing bond, it is likely a live electrical wire is bridging to the plumbing and the plumbing system is not grounded. This is an electrical shock hazard and potential fire danger; consult an electrician immediately!

Plastics

Plastic pipe is in wide use for domestic water supply and drainage, waste, and vent (DWV) pipe. For example, polyvinyl chloride

Polyvinyl chloride

Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

(PVC), chlorinated polyvinyl chloride

Chlorinated polyvinyl chloride

Chlorinated Polyvinyl chlorideDensity1.56 g/cm3Young's modulus 2.9-3.4 GPaTensile strength50-80 MPaElongation @ break20-40%Notch test2-5 kJ/m2Glass temperature 106 - 115 °CMelting point212 °CVicat B106 to 115 °C...

(CPVC), polypropylene

Polypropylene

Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...

(PP), polybutylene

Polybutylene

Polybutylene is a polyolefin or saturated polymer with the chemical formula n. It should not be confused with polybutene, a low molecular weight oligomer with a different repeat unit....

(PB), and polyethylene

Polyethylene

Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...

(PE) may be allowed by code for certain uses. Some examples of plastics in water supply systems are:

PVC
Polyvinyl chloride
Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

/CPVC
Chlorinated polyvinyl chloride
Chlorinated Polyvinyl chlorideDensity1.56 g/cm3Young's modulus 2.9-3.4 GPaTensile strength50-80 MPaElongation @ break20-40%Notch test2-5 kJ/m2Glass temperature 106 - 115 °CMelting point212 °CVicat B106 to 115 °C...

- 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.

PP
Polypropylene
Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...

- The material is used primarily in housewares, food packaging, and clinical equipment, but since the early 1970s has seen increasing use worldwide for both domestic hot and cold water. PP pipes are heat fused
Heat fusion
Heat fusion is a welding process used to join two different pieces of a thermoplastic. This process involves heating both pieces simultaneously and pressing them together. The two pieces then cool together and form a permanent bond. When done properly, the two pieces become indistinguishable from...

, preventing the use of glues, solvents, or mechanical fittings. PP pipe is often used in green building projects.

PBT
Polybutylene terephthalate
Polybutylene terephthalate is a thermoplastic engineering polymer, that is used as an insulator in the electrical and electronics industries. It is a thermoplastic crystalline polymer, and a type of polyester...

- 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
PEX
Cross-linked polyethylene, commonly abbreviated PEX or XLPE, is a form of polyethylene with cross-links. It is formed into tubing, and is used predominantly in hydronic radiant heating systems, domestic water piping and insulation for high tension electrical cables...

- 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

Piping and plumbing fittings

Fittings are used in pipe and plumbing systems to connect straight pipe or tubing sections, to adapt to different sizes or shapes, and for other purposes, such as regulating or measuring fluid flow...

and Valve

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. 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

Plumbing drainage venting

In modern plumbing, a drain-waste-vent is part of a system that removes sewage and greywater from a building and regulates air pressure in the waste-system pipes, facilitating flow. Waste is produced at fixtures such as toilets, sinks and showers, and exits the fixtures through a trap, a dipped...

article discusses the topic further, and introduces sewage treatment

Sewage treatment

Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...

Tap water versus bottled water

In modern Western society, levels of contaminants found in tap water vary for every household and plumbing system. A general conception regarding water is that bottled water is designed to be 'cleaner' than conventional tap water. However, in 1999, The Natural Resources Defense Council

Natural Resources Defense Council

The Natural Resources Defense Council is a New York City-based, non-profit, non-partisan international environmental advocacy group, with offices in Washington DC, San Francisco, Los Angeles, Chicago, and Beijing...

(NRDC) released controversial findings from a four year study on bottled water. The results of this study claimed that one-third of the waters tested contained levels of contamination—including synthetic organic chemicals, bacteria, and arsenic—in at least one sample that exceeded allowable limits under either state or bottled water industry standards or guidelines. However, the bottled water industry was quick to dispute the claim saying bottled water is one the most highly regulated food products under the FDA regulatory authority and that the FDA system worked extremely well when coupled with the International Bottled Water Association's Model Code and unannounced inspections.

Some municipalities in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

are making an effort to use tap water over bottled water on government properties and events. However, others voted the idea down, including voters in the state of Washington who repealed a bottled water tax via citizen initiative.

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."

Chlorine

Chlorine

is a disinfectant which is added to tap water in the United States. Chlorine can leave organic material like trihalomethanes and haloacetic acids

Haloacetic acids

Haloacetic acids are carboxylic acids in which a halogen atom takes the place of a hydrogen atom in acetic acid. Thus, in a monohaloacetic acid, a single halogen would replace a hydrogen atom. For example, chloroacetic acid would have the structural formula CH2ClCO2H. In the same manner, in...

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.

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

Cryptosporidium

Cryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhea in humans.Cryptosporidium is the organism most commonly isolated in HIV positive patients presenting with diarrhea...

outbreak in Milwaukee, Wisconsin, which led to several deaths and around 400,000 illnesses (see: Milwaukee Cryptosporidium outbreak

Milwaukee Cryptosporidium outbreak

The 1993 Milwaukee Cryptosporidium outbreak was a significant distribution of the Cryptosporidium protozoan in Milwaukee, Wisconsin, and the largest waterborne disease outbreak in documented United States history. The Howard Avenue Water Purification Plant was contaminated, and treated water...

). The University of Cincinnati recently completed a Tap Water Quality Analysis, funded by PUR, for major US cities.

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.

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)
Notes on Pipe -- Copper Pipe weights and max PSI

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