The present study was conducted to evaluate different types of irrigation water and their impact on heavy metals content in soil and date palm grown in Al-Hassa Oasis, Saudi Arabia. The investigated irrigation water included groundwater (GW), mixture of groundwater and drainage water (GW+DW), mixture of groundwater and tertiary treated wastewater (GW+TTWW) and mixture of groundwater, drainage water and tertiary treated wastewater (GW+DW+TTWW). The results of this study indicate that the water types used may cause one problem or another according to the water type. By applying the criteria used for interpreting water quality for irrigation, the most domain problems are salinity hazard and potential salinity. Therefore, it is expected that continuous irrigation without good water management (leaching requirements) can led to severe problems from the salinity point of view. The mixed waters (GW+DW +TTWW) have the highest effect on elemental composition of plants and soil followed by (GW+TTWW), (GW+DW) and then (GW). Generally, a significant difference in heavy metals concentrations for both treated soil and plants was found. The contents of the heavy metals in both soil samples and plants are compared with the worldwide standards. Based on these comparisons, the results concluded that the heavy metals in the soil and plants were in acceptable range.