Abstract: Saudi Arabia is facing an acute shortage of irrigation water because of limited and non-renewable groundwater resources coupled with a low annual mean rainfall and arid climatic conditions. Drainage water of different qualities is abundantly available in many regions of Saudi Arabia. The main objective of this study is to evaluate the drainage water quality for reuse to enhance the existing, inadequate irrigation supplies for sustainable agricultural production. Drainage water samples were collected from Al-Ahsa, Eastern Province, Saudi Arabia and analyzed chemically. The drainage water in D-1 is classified as C4S4 (very high salinity and very high sodium water), while D-2 drainage water is classified as C4S3 to C3S2 (very high salinity-high sodium water to high salinity-medium sodium water). The drainage waters of both D-1 and D-2 drains are free from sodicity hazards due to the low SAR values. Most of the drainage water is dominated by Na salts compared to other cations, such as Ca, Mg and K and has been classified as Na-Cl-HCO3 water. The trace elements and heavy metal concentration in drainage water from both drains are within the permissible limits for irrigation purposes. The nitrate (NO3) concentration is above the recommended limits for irrigation use. The bacterial contamination is very high in the drainage water of both drains and is not fit for irrigation without proper treatment. Based on the chemistry, the drainage water is not fit for irrigation due to the high total water salinity.