Water quality can be classified into four types:

Potable water: It is safe to drink, pleasant to taste, and usable for domestic purposes.

Palatable water: It is esthetically pleasing; it considers the presence of chemicals that do not cause a threat to human health.

Contaminated (polluted) water: It is that water containing unwanted physical, chemical, biological, or radiological substances, and it is unfit for drinking or domestic use.

Infected water: It is contaminated with pathogenic organism.

The water quality sensor measures water parameters such as conductivity, dissolved oxygen, pH, COD, residual chlorine, and turbidity through a variety of methods such as water chemical, physical and biological reactions, and provides data support for researchers, observers, and engineers. These are used in laboratory research, environmental management improvement, marine water quality assessment, hydraulic model calibration, sewage treatment, and other fields.