Pure water, referred to as purified water or pure water, is pure and clean water without impurities or bacteria. It is made of water that meets the hygienic standard of drinking water through electrodialysis, ion exchange, reverse osmosis, distillation and other appropriate treatment methods. Sealed in a container, without additives, colorless and transparent, and can be directly drunk. The space water and distilled water sold in the market are pure water. Sometimes this word is also commonly used for distilled water or rainwater extracted from chemical laboratories.