The current study aims to identify and assess the validity of groundwater in Tathleeth Region of Asir, Saudi Arabia for human and irrigation uses. The efforts, in this work, included a collection of different groundwater samples from Tathleeth area. After collection, the samples were put in appreciate containers, transferred to laboratory and kept for further analysis. The collection, preservation and analysis were done according to the standard methods. Then after, the physico-chemical proprieties of the collected groundwater samples as well as the concentration of different anions and cations were determined. Further, a bacteriological analysis was performed to evaluate the possible use of the groundwater, in this area, for human use. Finally, the obtained results were compared with the allowed limits set by Gulf Standard Specification (GSS).

Experimentally, many groundwater samples were collected from different wells, have different depths and distributed throughout the area of study. From all these groundwater samples, only nine samples were selected, to exclude repetition, and subjected to chemical and bacteriological analysis. The physical characteristics including: odor, color, turbidity and conductivity of the collected samples were determined. The values of different chemical parameters as: pH, total dissolved salts (TDS), total hardens, total alkalinity were measured according to the standard methods of analysis. In addition, the concentration of many anions (chloride, fluoride, nitrite, nitrate, ammonia and sulphate) and some major cations (iron, magnesium and calcium) were determined. Finally, a bacteriological analysis for E.coli, and T. coliform were performed for all collected samples.

The revealed results showed that pH has values ranged from 7.3 to 8.5 and the electrical conductivity exhibited values between 754 - 8944 µS cm-1 while the total dissolved salts between 520 to 6171 mg L-1. The results demonstrate the validity of certain samples for human uses and the suitability of most of samples for irrigation purposes.