How to judge the health of drinking water?

**I. Observe the appearance of water quality**

1. Clarity: Healthy domestic drinking water should be clear and transparent, without suspended matter, sediment, or turbidity. If the water appears cloudy, discolored, or has visible impurities, it may indicate problems with the water quality.

2. Odor: Normal domestic drinking water should have no peculiar smell. If the water has a pungent odor, such as chlorine smell, stench, or other abnormal odors, it may be polluted or contain excessive chemicals.

**II. Test water quality indicators**

1. pH value: The pH value of domestic drinking water should be between 6.5 and 8.5, slightly acidic to slightly alkaline. You can use pH test strips or professional water quality testing instruments for detection.

2. Hardness: The hardness of water is mainly determined by the content of calcium and magnesium ions in the water. Moderately hard water is more beneficial to human health. Generally speaking, a hardness between 120 and 180 mg/L is more appropriate. You can test it through water quality testing institutions or by using hardness test kits.

3. Residual chlorine content: In order to disinfect and sterilize, tap water usually contains a certain amount of residual chlorine. The residual chlorine content should be between 0.05 and 4 mg/L. Excessive residual chlorine content may have adverse effects on human health, such as causing skin allergies and respiratory irritation. You can use residual chlorine test strips or professional water quality testing instruments for detection.

4. Heavy metal content: Heavy metals in water such as lead, mercury, and cadmium are extremely harmful to human health. The heavy metal content in domestic drinking water should comply with national drinking water standards. Generally speaking, the lead content should not exceed 0.01 mg/L, the mercury content should not exceed 0.001 mg/L, and the cadmium content should not exceed 0.005 mg/L. You can test it through water quality testing institutions.

**III. Understand the water source and water treatment process**

1. Water source: The water sources for domestic drinking water mainly include surface water (such as rivers, lakes, reservoirs, etc.) and groundwater. Generally speaking, the water quality of groundwater is relatively good because it has been naturally filtered through the stratum. However, if groundwater is polluted, it will also pose a threat to human health. Understanding the water source situation can help you judge the quality of domestic drinking water.

2. Water treatment process: Tap water usually undergoes treatment processes such as sedimentation, filtration, and disinfection to remove impurities and harmful substances in the water. Understanding the water treatment process can give you a deeper understanding of the safety of domestic drinking water. If possible, you can check the water quality inspection report of the waterworks to understand the water quality after treatment.

**IV. Pay attention to physical reactions**

1. Feeling after drinking: Healthy domestic drinking water should have a refreshing taste and no peculiar smell or discomfort. If symptoms such as dry mouth, bitter taste, nausea, and vomiting occur after drinking, it may indicate problems with the water quality.

2. Skin reaction: If skin allergies such as itching and redness occur after taking a bath or washing the face with domestic drinking water, it may be that the water contains excessive chemicals or harmful substances.

In conclusion, judging whether domestic drinking water is healthy requires comprehensive consideration of multiple aspects such as water quality appearance, water quality indicators, water source and water treatment process, and physical reactions. If you have doubts about the quality of domestic drinking water, you can entrust professional water quality testing institutions to conduct tests to ensure the safety and health of drinking water.