58-500: The Water Services Regulation Authority , or Ofwat , is the body responsible for economic regulation of the privatised water and sewerage industry in England and Wales . Ofwat's main statutory duties include protecting the interests of consumers, securing the long-term resilience of water supply and wastewater systems , and ensuring that companies carry out their functions and are able to finance them. Ofwat primarily sets limits on
116-601: A 1 cm sample cell. Aquatic plants , algae , and other photosynthetic organisms can live in water up to hundreds of meters deep, because sunlight can reach them. Practically no sunlight reaches the parts of the oceans below 1,000 metres (3,300 ft) of depth. The refractive index of liquid water (1.333 at 20 °C (68 °F)) is much higher than that of air (1.0), similar to those of alkanes and ethanol , but lower than those of glycerol (1.473), benzene (1.501), carbon disulfide (1.627), and common types of glass (1.4 to 1.6). The refraction index of ice (1.31)
174-660: A board, plus an office of staff which carries out work delegated to them by the board. The Environment Agency is responsible for environmental regulation, and the Drinking Water Inspectorate for regulating drinking water quality. Water in Northern Ireland is regulated by the Northern Ireland Authority for Utility Regulation, and the supply and treatment is carried out by the government-owned Northern Ireland Water . There
232-436: A chemical as inorganic does not necessarily mean that it cannot occur within living things. Friedrich Wöhler 's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern organic chemistry . In Wöhler's era, there was widespread belief that organic compounds were characterized by a vital spirit . In the absence of vitalism, the distinction between inorganic and organic chemistry
290-481: A large amount of sediment transport that occurs on the surface of the earth. Deposition of transported sediment forms many types of sedimentary rocks , which make up the geologic record of Earth history . The water cycle (known scientifically as the hydrologic cycle) is the continuous exchange of water within the hydrosphere , between the atmosphere , soil water, surface water , groundwater, and plants. Water moves perpetually through each of these regions in
348-477: A property that is exploited by cetaceans and humans for communication and environment sensing ( sonar ). Metallic elements which are more electropositive than hydrogen, particularly the alkali metals and alkaline earth metals such as lithium , sodium , calcium , potassium and cesium displace hydrogen from water, forming hydroxides and releasing hydrogen. At high temperatures, carbon reacts with steam to form carbon monoxide and hydrogen. Hydrology
406-440: A structure of rigid oxygen atoms in which hydrogen atoms flowed freely. When sandwiched between layers of graphene , ice forms a square lattice. The details of the chemical nature of liquid water are not well understood; some theories suggest that its unusual behavior is due to the existence of two liquid states. Pure water is usually described as tasteless and odorless, although humans have specific sensors that can feel
464-412: A swimming pool when the light source is sunlight reflected from the pool's white tiles. In nature, the color may also be modified from blue to green due to the presence of suspended solids or algae. In industry, near-infrared spectroscopy is used with aqueous solutions as the greater intensity of the lower overtones of water means that glass cuvettes with short path-length may be employed. To observe
522-461: A variety of applications including high-temperature electrochemistry and as an ecologically benign solvent or catalyst in chemical reactions involving organic compounds. In Earth's mantle, it acts as a solvent during mineral formation, dissolution and deposition. The normal form of ice on the surface of Earth is ice I h , a phase that forms crystals with hexagonal symmetry . Another with cubic crystalline symmetry , ice I c , can occur in
580-489: Is visibly blue due to absorption of light in the region c. 600–800 nm. The color can be easily observed in a glass of tap-water placed against a pure white background, in daylight. The principal absorption bands responsible for the color are overtones of the O–H stretching vibrations . The apparent intensity of the color increases with the depth of the water column, following Beer's law . This also applies, for example, with
638-439: Is 917 kg/m (57.25 lb/cu ft), an expansion of 9%. This expansion can exert enormous pressure, bursting pipes and cracking rocks. In a lake or ocean, water at 4 °C (39 °F) sinks to the bottom, and ice forms on the surface, floating on the liquid water. This ice insulates the water below, preventing it from freezing solid. Without this protection, most aquatic organisms residing in lakes would perish during
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#1732802210708696-493: Is at a temperature of 273.16 K (0.01 °C; 32.02 °F) and a pressure of 611.657 pascals (0.00604 atm; 0.0887 psi); it is the lowest pressure at which liquid water can exist. Until 2019 , the triple point was used to define the Kelvin temperature scale . The water/vapor phase curve terminates at 647.096 K (373.946 °C; 705.103 °F) and 22.064 megapascals (3,200.1 psi; 217.75 atm). This
754-428: Is greater than the repulsion between the hydrogen atoms. The O–H bond length is about 0.096 nm. Other substances have a tetrahedral molecular structure, for example methane ( CH 4 ) and hydrogen sulfide ( H 2 S ). However, oxygen is more electronegative than most other elements, so the oxygen atom has a negative partial charge while the hydrogen atoms are partially positively charged. Along with
812-487: Is important in many geological processes. Groundwater is present in most rocks , and the pressure of this groundwater affects patterns of faulting . Water in the mantle is responsible for the melt that produces volcanoes at subduction zones . On the surface of the Earth, water is important in both chemical and physical weathering processes. Water, and to a lesser but still significant extent, ice, are also responsible for
870-470: Is it a noble gas (and therefore is not removed from the atmosphere through chemical reactions with other elements), but comparisons between the abundances of its nine stable isotopes in the modern atmosphere reveal that the Earth lost at least one ocean of water early in its history, between the Hadean and Archean eons. Any water on Earth during the latter part of its accretion would have been disrupted by
928-498: Is known as the critical point . At higher temperatures and pressures the liquid and vapor phases form a continuous phase called a supercritical fluid . It can be gradually compressed or expanded between gas-like and liquid-like densities; its properties (which are quite different from those of ambient water) are sensitive to density. For example, for suitable pressures and temperatures it can mix freely with nonpolar compounds , including most organic compounds . This makes it useful in
986-413: Is lower than that of liquid water. In a water molecule, the hydrogen atoms form a 104.5° angle with the oxygen atom. The hydrogen atoms are close to two corners of a tetrahedron centered on the oxygen. At the other two corners are lone pairs of valence electrons that do not participate in the bonding. In a perfect tetrahedron, the atoms would form a 109.5° angle, but the repulsion between the lone pairs
1044-571: Is no longer used, as it had no legal basis. The current chairman is Iain Coucher , who took up his position in July 2022, replacing Johnson Cox who had held the position since November 2012. Initially taking over from Rachel Fletcher as interim chief executive in April 2021, the current chief executive is David Black who was fully appointed to the role in April 2022. Every five years, Ofwat set limits on
1102-590: Is no separate charge for water for residents or companies in Northern Ireland. Instead, water is paid for by the rates system. The water industry regulator in Scotland is the Water Industry Commission for Scotland . Ofwat was set up in 1988, at the same time as 10 water authorities in England and Wales were privatised by flotation on the stock market. Its duties and powers are defined by
1160-422: Is poor at dissolving nonpolar substances. This allows it to be the " solvent of life": indeed, water as found in nature almost always includes various dissolved substances, and special steps are required to obtain chemically pure water . Water is the only common substance to exist as a solid , liquid, and gas in normal terrestrial conditions. Along with oxidane , water is one of the two official names for
1218-431: Is the main constituent of Earth 's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent ). It is vital for all known forms of life , despite not providing food energy or organic micronutrients . Its chemical formula, H 2 O , indicates that each of its molecules contains one oxygen and two hydrogen atoms , connected by covalent bonds . The hydrogen atoms are attached to
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#17328022107081276-458: Is the study of the movement, distribution, and quality of water throughout the Earth. The study of the distribution of water is hydrography . The study of the distribution and movement of groundwater is hydrogeology , of glaciers is glaciology , of inland waters is limnology and distribution of oceans is oceanography . Ecological processes with hydrology are in the focus of ecohydrology . The collective mass of water found on, under, and over
1334-681: The Earth's crust , although the compositions of the deep mantle remain active areas of investigation. All allotropes (structurally different pure forms of an element) and some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon ( graphite , diamond , buckminsterfullerene , graphene , etc.), carbon monoxide CO , carbon dioxide CO 2 , carbides , and salts of inorganic anions such as carbonates , cyanides , cyanates , thiocyanates , isothiocyanates , etc. Many of these are normal parts of mostly organic systems, including organisms ; describing
1392-485: The Moon-forming impact (~4.5 billion years ago), which likely vaporized much of Earth's crust and upper mantle and created a rock-vapor atmosphere around the young planet. The rock vapor would have condensed within two thousand years, leaving behind hot volatiles which probably resulted in a majority carbon dioxide atmosphere with hydrogen and water vapor . Afterward, liquid water oceans may have existed despite
1450-539: The Water Industry Act 1991 . The resulting companies are known as "water and sewerage companies"; this distinguishes them from around a dozen smaller companies which only provide water services, which were already in private hands in 1989 (having remained in private ownership since their creation in the 19th century). The water-only companies provide water to around 25% of the population in England and Wales. Before 1 April 2006, all regulatory powers rested with
1508-432: The elements hydrogen and oxygen by passing an electric current through it—a process called electrolysis . The decomposition requires more energy input than the heat released by the inverse process (285.8 kJ/ mol , or 15.9 MJ/kg). Liquid water can be assumed to be incompressible for most purposes: its compressibility ranges from 4.4 to 5.1 × 10 Pa in ordinary conditions. Even in oceans at 4 km depth, where
1566-529: The molar volumes of the liquid and solid phases, and L f {\displaystyle L_{\text{f}}} is the molar latent heat of melting. In most substances, the volume increases when melting occurs, so the melting temperature increases with pressure. However, because ice is less dense than water, the melting temperature decreases. In glaciers, pressure melting can occur under sufficiently thick volumes of ice, resulting in subglacial lakes . The Clausius-Clapeyron relation also applies to
1624-399: The water cycle consisting of the following transfer processes: Inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds — that is, a compound that is not an organic compound . The study of inorganic compounds is a subfield of chemistry known as inorganic chemistry . Inorganic compounds comprise most of
1682-449: The water cycle of evaporation , transpiration ( evapotranspiration ), condensation , precipitation, and runoff , usually reaching the sea. Water plays an important role in the world economy . Approximately 70% of the fresh water used by humans goes to agriculture . Fishing in salt and fresh water bodies has been, and continues to be, a major source of food for many parts of the world, providing 6.5% of global protein. Much of
1740-614: The Director General of Water Services. The staff who supported the role of the Director General were collectively known as the "Office of Water Services", which was abbreviated to "Ofwat". Ian Byatt was the Director General between 1989 and 2000; Philip Fletcher was Director General until 2006 and chairman until 2012. On 1 April 2006, the Director General was replaced by the Water Services Regulation Authority. The name "Office of Water Services"
1798-444: The Earth was younger and less massive , water would have been lost to space more easily. Lighter elements like hydrogen and helium are expected to leak from the atmosphere continually, but isotopic ratios of heavier noble gases in the modern atmosphere suggest that even the heavier elements in the early atmosphere were subject to significant losses. In particular, xenon is useful for calculations of water loss over time. Not only
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1856-538: The Indo-European root, with Greek ύδωρ ( ýdor ; from Ancient Greek ὕδωρ ( hýdōr ), whence English ' hydro- ' ), Russian вода́ ( vodá ), Irish uisce , and Albanian ujë . One factor in estimating when water appeared on Earth is that water is continually being lost to space. H 2 O molecules in the atmosphere are broken up by photolysis , and the resulting free hydrogen atoms can sometimes escape Earth's gravitational pull. When
1914-417: The average value of price rises above the rate of inflation ( RPI ) for the next five year asset management plan period . 52°28′35″N 1°53′55″W / 52.4763°N 1.8986°W / 52.4763; -1.8986 Water Water is an inorganic compound with the chemical formula H 2 O . It is a transparent, tasteless, odorless, and nearly colorless chemical substance . It
1972-577: The bent structure, this gives the molecule an electrical dipole moment and it is classified as a polar molecule . Water is a good polar solvent , dissolving many salts and hydrophilic organic molecules such as sugars and simple alcohols such as ethanol . Water also dissolves many gases, such as oxygen and carbon dioxide —the latter giving the fizz of carbonated beverages, sparkling wines and beers. In addition, many substances in living organisms, such as proteins , DNA and polysaccharides , are dissolved in water. The interactions between water and
2030-537: The boiling point, but with the liquid/gas transition the vapor phase has a much lower density than the liquid phase, so the boiling point increases with pressure. Water can remain in a liquid state at high temperatures in the deep ocean or underground. For example, temperatures exceed 205 °C (401 °F) in Old Faithful , a geyser in Yellowstone National Park . In hydrothermal vents ,
2088-785: The chemical compound H 2 O ; it is also the liquid phase of H 2 O . The other two common states of matter of water are the solid phase, ice , and the gaseous phase, water vapor or steam . The addition or removal of heat can cause phase transitions : freezing (water to ice), melting (ice to water), vaporization (water to vapor), condensation (vapor to water), sublimation (ice to vapor) and deposition (vapor to ice). Water differs from most liquids in that it becomes less dense as it freezes. In 1 atm pressure, it reaches its maximum density of 999.972 kg/m (62.4262 lb/cu ft) at 3.98 °C (39.16 °F), or almost 1,000 kg/m (62.43 lb/cu ft) at almost 4 °C (39 °F). The density of ice
2146-433: The desired result. Conversely, a pressure cooker can be used to decrease cooking times by raising the boiling temperature. In a vacuum, water will boil at room temperature. On a pressure/temperature phase diagram (see figure), there are curves separating solid from vapor, vapor from liquid, and liquid from solid. These meet at a single point called the triple point , where all three phases can coexist. The triple point
2204-486: The force of gravity . This property is relied upon by all vascular plants , such as trees. Water is a weak solution of hydronium hydroxide—there is an equilibrium 2H 2 O ⇌ H 3 O + OH , in combination with solvation of the resulting hydronium and hydroxide ions. Pure water has a low electrical conductivity , which increases with the dissolution of a small amount of ionic material such as common salt . Liquid water can be split into
2262-479: The form of snow . The gaseous state of water is steam or water vapor . Water covers about 71% of the Earth's surface, with seas and oceans making up most of the water volume (about 96.5%). Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor , clouds (consisting of ice and liquid water suspended in air), and precipitation (0.001%). Water moves continually through
2320-450: The fundamental stretching absorption spectrum of water or of an aqueous solution in the region around 3,500 cm (2.85 μm) a path length of about 25 μm is needed. Also, the cuvette must be both transparent around 3500 cm and insoluble in water; calcium fluoride is one material that is in common use for the cuvette windows with aqueous solutions. The Raman-active fundamental vibrations may be observed with, for example,
2378-416: The liquid is known as boiling ). Sublimation and deposition also occur on surfaces. For example, frost is deposited on cold surfaces while snowflakes form by deposition on an aerosol particle or ice nucleus. In the process of freeze-drying , a food is frozen and then stored at low pressure so the ice on its surface sublimates. The melting and boiling points depend on pressure. A good approximation for
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2436-753: The liquid or solid state can form up to four hydrogen bonds with neighboring molecules. Hydrogen bonds are about ten times as strong as the Van der Waals force that attracts molecules to each other in most liquids. This is the reason why the melting and boiling points of water are much higher than those of other analogous compounds like hydrogen sulfide. They also explain its exceptionally high specific heat capacity (about 4.2 J /(g·K)), heat of fusion (about 333 J/g), heat of vaporization ( 2257 J/g ), and thermal conductivity (between 0.561 and 0.679 W/(m·K)). These properties make water more effective at moderating Earth's climate , by storing heat and transporting it between
2494-1070: The long-distance trade of commodities (such as oil, natural gas, and manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating in industry and homes. Water is an excellent solvent for a wide variety of substances, both mineral and organic; as such, it is widely used in industrial processes and in cooking and washing. Water, ice, and snow are also central to many sports and other forms of entertainment, such as swimming , pleasure boating, boat racing , surfing , sport fishing , diving , ice skating , snowboarding , and skiing . The word water comes from Old English wæter , from Proto-Germanic * watar (source also of Old Saxon watar , Old Frisian wetir , Dutch water , Old High German wazzar , German Wasser , vatn , Gothic 𐍅𐌰𐍄𐍉 ( wato )), from Proto-Indo-European * wod-or , suffixed form of root * wed- ( ' water ' ; ' wet ' ). Also cognate , through
2552-418: The oceans and the atmosphere. The hydrogen bonds of water are around 23 kJ/mol (compared to a covalent O-H bond at 492 kJ/mol). Of this, it is estimated that 90% is attributable to electrostatics, while the remaining 10% is partially covalent. These bonds are the cause of water's high surface tension and capillary forces. The capillary action refers to the tendency of water to move up a narrow tube against
2610-487: The oceans may have always been on the Earth since the beginning of the planet's formation . Water ( H 2 O ) is a polar inorganic compound . At room temperature it is a tasteless and odorless liquid , nearly colorless with a hint of blue . The simplest hydrogen chalcogenide , it is by far the most studied chemical compound and is sometimes described as the "universal solvent" for its ability to dissolve more substances than any other liquid, though it
2668-488: The oxygen atom at an angle of 104.45°. In liquid form, H 2 O is also called "water" at standard temperature and pressure . Because Earth's environment is relatively close to water's triple point , water exists on Earth as a solid , a liquid , and a gas . It forms precipitation in the form of rain and aerosols in the form of fog . Clouds consist of suspended droplets of water and ice , its solid state. When finely divided, crystalline ice may precipitate in
2726-402: The presence of water in their mouths, and frogs are known to be able to smell it. However, water from ordinary sources (including mineral water ) usually has many dissolved substances that may give it varying tastes and odors. Humans and other animals have developed senses that enable them to evaluate the potability of water in order to avoid water that is too salty or putrid . Pure water
2784-437: The pressure is 400 atm, water suffers only a 1.8% decrease in volume. The viscosity of water is about 10 Pa· s or 0.01 poise at 20 °C (68 °F), and the speed of sound in liquid water ranges between 1,400 and 1,540 metres per second (4,600 and 5,100 ft/s) depending on temperature. Sound travels long distances in water with little attenuation , especially at low frequencies (roughly 0.03 dB /km for 1 k Hz ),
2842-735: The prices charged for water and sewerage services, taking into account proposed capital investment schemes (such as building new wastewater treatment works) and expected operational efficiency gains. The most recent review was carried out in 2019; reviews are carried out every five years, with the next due to take place in December 2024. The Water Act 2014 extended retail competition to all non-household customers of English water companies from April 2017 and provided for possible future competition in wholesale markets. Ofwat's role includes regulating such water and wastewater markets and promoting effective competition wherever appropriate. Ofwat consists of
2900-405: The prices which water companies in England and Wales can charge to their customers; this process is known as a price review or periodic review. Ofwat has carried out six price reviews so far – in 1994 (PR94), 1999 (PR99), 2004 (PR04), 2009 (PR09), 2014 (PR14) and 2019 (PR19). The most recent, PR19, set price limits for 2020–2025. Ofwat sets a so-called "K factor" in companies' licences which determine
2958-587: The rate of change of the melting temperature with pressure is given by the Clausius–Clapeyron relation : d T d P = T ( v L − v S ) L f {\displaystyle {\frac {dT}{dP}}={\frac {T\left(v_{\text{L}}-v_{\text{S}}\right)}{L_{\text{f}}}}} where v L {\displaystyle v_{\text{L}}} and v S {\displaystyle v_{\text{S}}} are
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#17328022107083016-413: The subunits of these biomacromolecules shape protein folding , DNA base pairing , and other phenomena crucial to life ( hydrophobic effect ). Many organic substances (such as fats and oils and alkanes ) are hydrophobic , that is, insoluble in water. Many inorganic substances are insoluble too, including most metal oxides , sulfides , and silicates . Because of its polarity, a molecule of water in
3074-488: The surface of a planet is called the hydrosphere . Earth's approximate water volume (the total water supply of the world) is 1.386 billion cubic kilometres (333 million cubic miles). Liquid water is found in bodies of water , such as an ocean, sea, lake, river, stream, canal , pond, or puddle . The majority of water on Earth is seawater . Water is also present in the atmosphere in solid, liquid, and vapor states. It also exists as groundwater in aquifers . Water
3132-537: The surface temperature of 230 °C (446 °F) due to the increased atmospheric pressure of the CO 2 atmosphere. As the cooling continued, most CO 2 was removed from the atmosphere by subduction and dissolution in ocean water, but levels oscillated wildly as new surface and mantle cycles appeared. Geological evidence also helps constrain the time frame for liquid water existing on Earth. A sample of pillow basalt (a type of rock formed during an underwater eruption)
3190-403: The temperature can exceed 400 °C (752 °F). At sea level , the boiling point of water is 100 °C (212 °F). As atmospheric pressure decreases with altitude, the boiling point decreases by 1 °C every 274 meters. High-altitude cooking takes longer than sea-level cooking. For example, at 1,524 metres (5,000 ft), cooking time must be increased by a fourth to achieve
3248-458: The upper atmosphere. As the pressure increases, ice forms other crystal structures . As of 2024, twenty have been experimentally confirmed and several more are predicted theoretically. The eighteenth form of ice, ice XVIII , a face-centred-cubic, superionic ice phase, was discovered when a droplet of water was subject to a shock wave that raised the water's pressure to millions of atmospheres and its temperature to thousands of degrees, resulting in
3306-441: The winter. Water is a diamagnetic material. Though interaction is weak, with superconducting magnets it can attain a notable interaction. At a pressure of one atmosphere (atm), ice melts or water freezes (solidifies) at 0 °C (32 °F) and water boils or vapor condenses at 100 °C (212 °F). However, even below the boiling point, water can change to vapor at its surface by evaporation (vaporization throughout
3364-809: Was recovered from the Isua Greenstone Belt and provides evidence that water existed on Earth 3.8 billion years ago. In the Nuvvuagittuq Greenstone Belt , Quebec, Canada, rocks dated at 3.8 billion years old by one study and 4.28 billion years old by another show evidence of the presence of water at these ages. If oceans existed earlier than this, any geological evidence has yet to be discovered (which may be because such potential evidence has been destroyed by geological processes like crustal recycling ). More recently, in August 2020, researchers reported that sufficient water to fill
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