Abstarct: Continuous monitoring of water quality parameters is a vital issue in providing safe and healthy drinking water. Contaminants and toxicants can endanger the safety of drinking water resources in various ways, intentionally or accidentally. Also, the short time required for the toxicants to spread to the consumers increases the need for emergency response to this vital issue. On the other hand, equipping water supply systems with a network of different online monitoring sensors is very expensive and almost non-operational. In this study, the performance of simple and low-cost water quality parameters was evaluated with the aim of emergency detection of accidental or intentional pollution caused by conventional toxic substances. Unlike natural and conventional pollutions, accidental and intentional pollutions require a quick response due to their nature of occurrence and lack of knowledge of the time of occurrence. The design of a network of sensors to detect contamination in water supply systems and water sources is due to this uncertain and unpredictable nature of contamination. For this purpose, in this research, performance evaluation of simple and low-cost water quality sensors (pH, UV-254, redox potential or ORP, electrical conductivity or EC, turbidity and temperature) in detection of a conventional herbicide (glyphosate) as a toxic contaminant, with a maximum allowable value of 7 ppm in water, has been investigated. A pilot has been designed to simulate contamination injection by the pump and record online monitoring parameters. Changes in water quality parameters were recorded in the presence of three concentrations of 2, 4 and 6 ppm of glyphosate herbicide. All experiments were performed at laboratory temperature in the range of 20 to 25 ° C. The results showed that pH and ORP have the highest sensitivity during the experimental stages, so that at a concentration of 0.6 mg/L, the pH decreased from 7.4 to 6.3 (aboat15%) and ORP increased from 273 mV to 297 mV (aboat 9%). Electrical conductivity and turbidity also changed in the presence of contamination, but less than the previous two parameters. The turbidity and temperature changes were such that the range of fluctuations due to water velocity and turbulence within the canal covered these changes. The UV-254 experiment was performed with four samples of pollutants with different concentrations outside the pilot cycle, which, according to the resulting diagram, by increasing the concentration of contaminats the adsorption also increased at a constant wavelength