Classification of Water

1.Groundwater and surface water

Groundwater - has less organic and microbial pollution, while calcium magnesium plasma dissolves more and has higher hardness, making it prone to scaling; Sometimes iron/manganese/fluoride ions exceed the standard and cannot meet the needs of production and domestic water use.

Surface water - has more organic and microbial pollution than groundwater. If the area belongs to limestone areas, the surface water often has higher hardness.

2.Hard water and soft water

Hard water - The total concentration of metal ions such as calcium and magnesium in water is called hardness. Hard water has a significant impact on production water such as boilers, and it should be softened/desalinated. A hardness greater than 200mg/L is usually referred to as hard water.

Soft water - water with lower hardness. It generally refers to reducing or removing the content of calcium and magnesium ions in water to a certain extent.

3.Raw water and purified water

Raw water - usually refers to the inflow of water treatment equipment, such as commonly used urban tap water (internationally known as domestic drinking water)/suburban groundwater/outdoor surface water, etc. The water quality is often measured by TDS value (total dissolved solids content in water), and the TDS value of Chinese urban tap water is usually 100-400ppm.

Purified water - After being treated by water treatment facilities, the raw water is called purified water.

4. Pure water and distilled water

Pure water - After being treated with a complete set of water treatment facilities such as reverse osmosis and sterilization devices, the raw water removes the vast majority of inorganic salt ions, microorganisms, and organic impurities, making it a pure water that can be directly consumed.

Distilled water - Pure water prepared by distillation, usually not used for drinking.

5.Pure water and ultrapure water

Pure water - deionized water prepared by methods such as reverse osmosis, distillation, and ion exchange, with a TDS value typically<5PPm and a conductivity typically<10 μ S/cm (resistance value>0.1M Ω. cm).

Ultra pure water - obtained by further purifying and deionizing pure water using methods such as ion exchange, distillation, and electrostatic desalination, with an unmeasurable TDS value and conductivity typically<0.1 μ S/cm (resistance value>10M Ω. cm), its ions are almost completely removed. The theoretical purest water resistance value is 18.25 M Ω. cm.