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 (Water Fittings) Regulations 1999 notifications to be given. Part III deals with enforcement, penalties, tests and disputes. Schedule 1 categorizes water into five different levels fluid categories for "wholesomeness", while schedule 2 provides further explanation of terms used within the body of the regulations. Schedule 3 revokes previous water byelaws. Wholesome water supplied by a water undertaker and complying with the requirements of regulations made under section 67 of the Water Industry Act 1991. Water in fluid category 1 whose aesthetic quality is impaired owing to- Fluid which represents a slight health hazard because of the concentration of substances of low toxicity, including any