drinking water quality standards
Drinking Water Quality Standard Reference Materials
- 《Hygienic Standards for Drinking Water》 (GB5749-85) issued in 1985
- 《Hygienic Standards for Drinking Water》 (GB5749-2006)
Drinking water quality standards related indicators
TDS
TDS (total dissolved solids), that is, the total dissolved solids concentration in water (mg/L), mainly reflects the concentration of Ca2+, Mg2+, Na+, K+ plasma in the water, and has a good correspondence with the hardness and conductivity of the water. It cannot reflect the concentration of harmful heavy metal ions in the water, how many bacteria there are in the water, the concentration of organic matter, whether the nitrite concentration exceeds the standard, and whether there are any pesticide residues. “Water Hygiene Standard” TDS (i.e. total dissolved solid matter) ≤ 1000mg/L.
Color
The color of water refers to the quantitative measurement of the color of natural water or various treated waters. Natural water often appears in light yellow, light brown, yellow-green and other colors. Discoloration is caused by humus, organic matter or inorganic matter dissolved in the water.
The standard stipulates that the color of drinking water should not exceed 15 degrees.
Turbidity
It is an important indicator of the physical properties of water. Used to indicate the extent to which suspended matter in the water blocks the passage of light. Generally speaking, the more insoluble matter in water, the higher the turbidity. Turbidity is caused by the presence of particulate matter such as clay, sludge, colloidal particles, plankton, and other microorganisms. It is used to characterize the turbidity of water and is an important indicator of water quality.
The turbidity of drinking water should not exceed 5 degrees (NTU)
pH
The pH value is between 0-14. The pH value of water is the standard for testing the acidity and alkalinity of water quality. When the PH value is less than 7, the PH value is acidic; when the PH value is greater than 7, the water is alkaline. GB5749-2006 “Hygienic Standards for Drinking Water” stipulates that the PH value of drinking water is 6.5-8.5 as a normal value, and it is designated as a normal value.
Microorganisms in drinking water quality standards
Total number of colonies (CFU/mL) 500
Toxicological indicators
Arsenic (mg/L) 0.05
Fluoride (mg/L) 1.2
Nitrate (calculated as N, mg/L) 20
Sensory properties and general chemical indicators
Chroma (Platinum Cobalt Chroma Unit) 20
Turbidity (NTU – Scattering Turbidity Unit) 3
5 when water source and water purification technical conditions are limited
pH (pH unit) not less than 6.5 and not more than 9.5
Total dissolved solids (mg/L) 1500
Total hardness (calculated as CaCO3, mg/L) 550
Oxygen consumption (CODMn method, calculated as O2, mg/L) 5
Iron (mg/L) 0.5
Manganese (mg/L) 0.3
Chloride (mg/L) 300
Sulfate (mg/L) 300