This study investigates the hydrological, hydrogeological and environmental conditions in Amran basin that covers approximately 1590 km². The importance of this study is to identify the different environmental conditions associated with the socio-economic development, increase of population of Amran basin, depletion of groundwater, production of large quantity of industrial and domestic wastewater and the increase in using the fertilizer and pesticides for agriculture purposes. The socio-economic development affects badly the quality of the groundwater resources to be used directly for domestic purposes. The collected of water samples of groundwater resources analyzed for their physical, chemical and biological characteristics. According to the obtained results, some of groundwater wells are contaminated biologically by faecal coliform and chemically by high contents of salinity (calcium, bicarbonate, sulfate and nitrate). The groundwater resources in part of the study area unsuitable for irrigation purposes whereas, the water is classified as high salinity hazard with low sodium hazard (C3-S1). Also thermodynamic analyses were performed using Phreeqci software to state the capability of water resources to precipitate or to dissolve the aquifer matrix. Seventy seven percent of the water samples are free of the fecal and total coliform respectively; these percentages are mainly limited to the deep wells. Therefore about 23% of the samples are contaminated with coliform bacteria thus need treatment of disinfection and coagulation before being used for drinking.