The deficiency of potassium (K) has resulted in decreasing the yield and quality of food grains. Moreover, with decreasing water resources the use of wastewater in agriculture as an alternative source of water and nutrients is being debated. This study was therefore undertaken to test wastewater for its suitability as irrigation water together with uniform basal doses of nitrogen (N) and phosphorus (P) and varying doses of potassium (K 0, K 20 , K 40 and K 60 ). It was observed that the plants receiving wastewater as a source of irrigation water performed better with a lower K dose. Potassium at 20 kg ha À1 along with wastewater resulted in better growth, photosynthetic rate (P N ), stomatal conductance (g s ) and yield of the chickpea (Cicer arietinum L.). Thus fertilizer rates could be lowered with the use of wastewater which can serve not only as the source of water but of nutrients also. However, regular monitoring of wastewater and soil for any buildup of heavy metal is necessary. The physical and chemical parameters of wastewater were also tested and most of them were found to be well within the permissible limits as set by the Food and Agriculture Organization (FAO).