The State Administration for Quality and Technical Supervision issued GB173223-1998 "Bottled Drinking Purified Water" and GB17324-1998 "Sanitary Standards for Bottled Drinking Purified Water" in April 1998. In these two standards, there are a total of 4 sensory indicators, 4 physicochemical indicators, and 11 hygiene indicators.

1. Sensory indicators

Sensory indicators include chromaticity, turbidity, odor, and visible substances to the naked eye. These indicators are the most basic indicators in the quality control of purified water, and their standard values are based on the standards of drinking water (i.e. tap water). Most manufacturers produce purified water from tap water, which undergoes a process of coarse filtration, fine filtration, and deionized purification. Therefore, generally, purified water can meet the values required by national standards.

2. Physical and chemical indicators

The most important physical and chemical indicators are conductivity and consumption. Conductivity is a characteristic indicator of pure water, reflecting the purity level of pure water and the quality of production process control. Due to the fact that drinking water does not undergo deionized purification, this indicator is not considered. For pure water, "purity" is its most basic requirement, as high levels of metal elements and microorganisms can lead to high electrical conductivity. So, water with lower conductivity is purer.

Another important indicator in the national health standards is the nitrite content. Nitrite mainly comes from nitrate in the soil near the water source, with higher nitrate content in saline alkali land, heavily applied nitrate fertilizers, and molybdenum deficient soil. According to the national standard, nitrite should not exceed 0.002mg/L.

3. Microbial indicators

The microbiological indicators in the national standard specify four items: total bacterial count, coliform bacteria, pathogenic bacteria, mold, and yeast. From the recent situation of pure water testing, microbial indicators are one of the indicators that are relatively prone to exceeding the standard. This is because microbial contamination is reflected in various stages of production, processing, transportation, and sales of purified water.

In production and processing, workers do not pay attention to personal hygiene, and the cleaning and disinfection of recycled bottles are not strict. Some manufacturers even use recycled bottle caps again to reduce costs. Due to the deformation of recycled bottle caps, unsealed bottle mouths may cause microbial contamination. The exceedance of microorganisms reflects the degree of water pollution. When Escherichia coli reaches a certain threshold, it can cause diarrhea in the human body.

4. Metal indicators

The metal element index specifies the content of lead, arsenic, and copper in the standard. Lead and arsenic are required to not exceed 0.1mg/L, and their main sources are the environment affected by human activities, including soil, river pollution, and so on. Lead and arsenic are toxic and harmful elements. Lead can enter the human body through the respiratory or digestive tract and accumulate in the body. When the lead content in the blood is 0.6-0.8mg/L, it can damage the internal organs, and arsenic compounds can cause poisoning. Therefore, their content should be as small as possible. Copper, on the other hand, is not allowed to exceed 1.0mg/L in the standard. Although copper is not a harmful element, it is not a substance that is better with more. For pure water, it is also one of the indicators to measure its purity.

5. Organic index

The organic matter indicators are mainly reflected in the national standards for the content of chloroform and carbon tetrachloride. Due to the quality issues of bottled purified water mainly focusing on exceeding microbiological testing standards, many manufacturers do not start from production processes and quality management, but only attempt to solve the problem of microbial contamination in purified water by measuring the quantity. Commonly used disinfectants are chlorine containing disinfectants such as chlorine dioxide. Bottled purified water can produce some new organic halogenated compounds due to chlorination disinfection, mainly composed of chloroform and carbon tetrachloride, as well as small amounts of chloromethane, bromodichloromethane, dibromochloromethane, and bromoform, collectively known as halogenated hydrocarbons.

After testing, it was found that the halogenated alkane content in drinking water and tap water that have been disinfected with chlorine is generally higher than that in source water. Among them, the content of carbon tetrachloride is relatively high and poses certain hazards to the human body. In the national standard GB17324-1998, it is clearly stipulated that the content of carbon tetrachloride in drinking purified water shall not exceed 0.02mg/L and 0.001mg/L, respectively.

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