Large quantities of water are produced during oil extraction in Oman, which form the largest single waste in the entire oil producing business. This water is utilized for reservoir pressure maintenance by injection into shallow and deep sub surface formations at oil fields. According to Oman environmental regulations, this practice has to stop very soon. The water is saline and heavily contaminated with oil. It is, therefore, desirable to find a method that utilizes the large quantity of oil contaminated water after treatment. The overall objective of this study was to assess the suitability of using treated water for irrigation. Investigation on the effect of using treated water on soil physical properties was also conducted. Other objectives were to investigate the effect of treated water on heavy metals accumulation in soil and to determine if there is any relationship between salinity, pH, and sodicity with time, depth of soil, water application rates, and type of water and their interactions. A pilot scale study was conducted at Sultan Qaboss University to treat the produced water continuously using a combined air floatation-adsorption process. The process has successfully reduced oil in the water from 100-300 ppm to less than 0.5 cer ppm. A comparison study between the treated water and fresh water has been performed to test their effect on soil physical and chemical properties. Because of the salinity in water, treated water was found to have significant effect on the electrical CO conductivity of the soil saturation paste extract with no significant effect on the pH of the soil. It has been found from the study that the use of treated water caused a sodicity problem, which has adverse effects on the physical properties of the soil such as infiltration rate and saturated hydraulic conductivity. No significant difference was observed in heavy metals accumulation when fresh and treated water CCU were used.