Some may ask: Isn’t purified water pollution-free and intended for human consumption? Why would it still need testing? The answer is yes—testing is absolutely necessary. This article will briefly explain why.

In fact, purified water, also known as mineral water, comes from natural water sources. Such sources have stricter water quality requirements. First, they must originate from natural springs; second, geological and mining authorities must conduct surveys and implement proper source protection measures, as these are considered mineral resources. Since purified water is for human drinking, its quality is subject to stringent standards. Just like tap water, purified water must undergo water quality testing before human consumption to verify that all indicators meet relevant specifications. Only when these indicators comply with the standards can it be officially called “purified water”.

What specific indicators are tested for purified water? The list is neither overly extensive nor too short. Based on China’s mandatory standard GB 8538-2016, the main testing items include:

• Physical and chemical indicators: color, total dissolved solids (TDS), total alkalinity, total hardness, turbidity, total acidity
• Heavy metals: iron, copper, zinc, total chromium, silver, aluminum, antimony, cobalt, etc.
• Characteristic pollutants: cyanide, nitrate, nitrite, phosphate, etc.
• Microbial contaminants: coliform bacteria, fecal streptococci, Pseudomonas aeruginosa, etc.

These indicators are monitored in real time using water quality testing instruments, and all results must comply with relevant standards for drinking water to ensure safe consumption of purified water.