Tap water ( running water ) is part of indoor plumbing, which became available in the developed world in the late 19th century and common in the mid-20th century.
The provision of tap water is a massive infrastructure of piping, pumps, 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 for the same amount.
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 fluoride are added to the tap water in an effort to improve public dental health. In some countries, this remains a controversial issue for a portion 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 stick to bottled water instead. An example is the recent discovery of potentially hazardous nitrates in the public water supply in Kingman, Arizona.
Tap water uses
According to a 1999 American Water Works Association study 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)
Of all water supplied to studied homes annually, for perspective, 42 percent was for indoor purposes and 59 percent for outdoor purposes.
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.
- Municipal water supply
- Water wells
- 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.
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 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":
- 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 incapatable 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 inst
EWG Investigation | U.S. Tap Water Quality Database
The National Tap Water Testing database is available at www.ewg.org/sites/tapwater/. Unregulated contaminants. Tap water contaminants that have been found by water utilities and ...
EWG Investigation | U.S. Tap Water Quality Database
EPA Programs Leading to Testing or Regulation of Unregulated Contaminants. Safe Drinking Water Act programs that require water suppliers to test for unregulated contaminants, and ...
Water Tests: AWF Water Testing Guide
Should I Test my Water? Yes - It is important to know your water’s composition because ... What makes the Tap Master better than other reverse osmosis systems? 4. What are the ...
COOPERPROOF.com ™ - a subsidiary of Adeona Pharmaceuticals
COPPERFREE.com - Copper in tap water testing cards ... Being able to measure copper in your tap water is an important step in improving the quality of health for the average person ...
Lead and Drinking Water Tap Testing
As noted earlier, although EPA's regulations and Lead and Copper Rule guidance Lead and Drinking Water Tap Testing
Aquarium Maintenance & Water Quality: Test and Treat Tap Water to ...
Don't take the quality of your tap water for granted. If you draw your water from a well, nature may not be providing you the perfect balance. If you are using tap water from your ...
NYC Places 2nd in Tap Water Taste Test - Gothamist
2008 regional tap water taste-off contest. Photos courtesy of AMNH/Matt Shanley. This morning the American Museum of Natural History hosted a Tap Water Taste-off on their steps.
YouTube - Tap water test
LOL save money and the earth, if you have clean water in your area , drink it! image all the plastic we can save...
Safety Forum - Tap Water Testing
Online bulletin board forum where safety professionals meet to discuss osha compliance and other safety topics
Taste Test Pits Bottled Water Against Tap Water - wcco.com
Tap water from the Twin Cities competed against two brands of pricey bottled water Tuesday on Nicollet Mall in Minneapolis. ...