Water pollution is caused by harmful chemical substances to reduce or lose the use value of water and pollute the environment. Acid, alkali, oxidant, copper, cadmium, mercury, arsenic and other compounds in sewage, benzene, dichloroethane, ethylene glycol and other organic poisons will poison aquatic organisms and affect the drinking water source. When the organic matter in the sewage is decomposed by microorganisms, it consumes oxygen in the water and affects the life of aquatic organisms. After the dissolved oxygen in the water is exhausted, the organic matter is anaerobic decomposed to produce hydrogen sulfide, mercaptan and other odorous gases, which further worsens the water quality.

In introducing the government's tasks in 2019, Li Keqiang pointed out that we should speed up the implementation of rural drinking water safety. This year and next, we should solve the problem of drinking water safety for people with drinking water difficulties, improve the level of water supply guarantee for 60 million rural people, and let the purified water enter thousands of households. In recent years, people pay more and more attention to the safety of drinking water. Wang Canfa, a professor at China University of political science and law, believes that the safety of drinking water is directly related to the health of the people and people's livelihood. If the drinking water is unsafe and polluted, it may lead to various diseases. To improve the safety of drinking water is to ensure that drinking water does not damage people's health.

According to another introduction, "due to the dispersion of drinking water intakes in rural areas, the area that needs to be protected is very large, but now the risk of non-point source pollution in some rural areas is relatively large. The first is the use of pesticides, and the second is shallow groundwater pollution. All these lead to certain risks when people living in rural areas take water. In addition, due to the large area involved, it is difficult to monitor all aspects of rural drinking water sources, and even the situation of each household may be different, and the relevant monitoring institutions are generally unable to monitor every household's drinking water. "

In some places, including some rural areas, the available sources of drinking water are relatively limited and generally depend on natural water sources such as rivers and lakes; Secondly, the problem of water quality. Now many rural areas are using tap water, and tap water will cause secondary pollution of water quality. In the face of this situation, the installation of water purifier is the best choice.