Water is essential for human being use and livelihoods ecosystem functioning and services, and the survival of all living species. Water Quality Indices aim at giving a single value to water quality of a source reducing numerous parameters into a simpler expression and enabling easy interpretation of monitoring data. Standard water quality model was used to assess the groundwater quality for drinking purposes in Surman (Zakry locality), Libya. Ten samples from different sites were collected and analyzed for understanding the hydrochemical characteristics and the suitability for drinking purposes. Ten parameter were considered for calculating the water quality index, these are calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, pH, total dissolved solids and total hardness. The results obtained from the water quality index were calculated, and found to be within the observed parameters which ranges from 35.69 to 66.05. The total dissolved solids (TDS) were in the majority of samples higher than the permissible limit. The pH values tend slightly toward the acidic range............... Keywords:....... WQI, drinking purposes, Groundwater quality, moderate, Surman.