Underground pipe network drainage water quality monitoring is an important work to ensure the quality and environmental safety of underground pipe network drainage. By monitoring different water quality indicators, problems in underground pipe network drainage can be found and solved in a timely manner, and the environment and people's health can be protected. Here are some common indicators for monitoring the water quality of underground pipe network drainage:
1.pH:
The pH value is an indicator of the acidity and alkalinity of the water body, and for the drainage of the underground pipe network, the change of the pH value can reflect the acidity and alkalinity of the water body. A pH that is too high or too low can be harmful to the environment and organisms, so the pH range needs to be monitored and controlled.
2.Suspended solids:
Suspended solids refer to solid particles suspended in water, including sediment, sediment, suspended particles, etc. High levels of suspended solids in underground network drainage may lead to turbidity of the water body, affecting water quality and the environment.
3.Dissolved Oxygen:
Dissolved oxygen refers to the oxygen molecules dissolved in water and is very important for the survival and respiration of organisms in the water body. The content of dissolved oxygen in the drainage of the underground pipe network can reflect the degree of oxygen enrichment of the water body, and too low dissolved oxygen content may lead to the lack of oxygen in the water body, causing harm to aquatic organisms.
4.Chemical Oxygen Demand (COD):
Chemical oxygen demand refers to the amount of oxygen required for the oxidation of organic matter in water, which can reflect the content of organic matter in the water body and the degree of pollution. High COD values in underground network drainage may lead to eutrophication and deterioration of water quality.
5.Total Nitrogen and Total Phosphorus:
Total nitrogen and total phosphorus are common nutrients in underground pipe network drainage, too high total nitrogen and total phosphorus content may lead to eutrophication of water bodies, causing algae overgrowth and water quality problems, the phosphorus content in biological sewage is 2 20mg l, of which organic phosphorus is 1 5mg l, inorganic phosphorus is 1 15mg l, the nitrogen content in domestic sewage is generally 20 80mg l, of which organic nitrogen is 8 35mg l, ammonia nitrogen is 12 50mg l, and the content of nitrate nitrogen and nitrite nitrogen is low.
6.Heavy Metals:
The content of heavy metals in underground pipe network drainage is an important monitoring indicator, such as lead, mercury, cadmium, etc. Excessively high levels of heavy metals may cause serious harm to the environment and human health.
7.Residual chlorine:
In general, the content of residual chlorine does not exceed 03 mg l, which is to ensure the reproduction of microorganisms during the delivery process. 
Through the monitoring and analysis of the monitoring indicators of the drainage water quality of the underground pipe network, the problems existing in the drainage of the underground pipe network can be found and solved in a timely manner, and the environment and people's health can be protected. At the same time, for the drainage of underground pipe networks in different regions and for different purposes, it is also necessary to select corresponding monitoring indicators and standards according to the specific situation to ensure the quality and environmental safety of underground pipe network drainage.