Properties of water equal to that of the hydrogen ion (), which gives a pH of 7 at 25 °C. Action of water on rock over long periods of time typically leads to weathering and water erosion, physical processes that convert solid rocks and minerals into soil and sediment, but under some conditions chemical reactions with water occur as well, resulting in metasomatism or mineral hydration, a type of chemical alteration of a rock which produces clay minerals. It also occurs when Portland cement hardens. Water ice can form clathrate compounds, known as clathrate hydrates, with a variety of small molecules that can
Water supply and sanitation in the Republic of Ireland 14 November 2002, authorities in Ireland were cited by the European Court of Justice over the microbiological contamination of hundreds of public and private water supplies. The EU's Drinking Water Directive requires an absence of E. coli in drinking water supplies to protect human health. The Environmental Protection Agency's 2011 report on drinking water stated that drinking water quality in public water supplies was continuing to improve. At that time, chemical standard compliance stood at 99.5%. 1.3% of supplies were found to have had E.coli, a reduction of 86% since 2005. 10.2% of private group supplies had E.coli, down from