A pot experiment carried out to evaluate the impact of nitrate concentration in irrigation water as one of the miscellaneous or accidental effects on irrigation water on the growth of wheat and lettuce plants. The pots are filled with sandy soil, irrigated at field capacity with different concentration of nitrate; 0, 10, 20, and 50 mg L-1 from planting to harvest. The results indicated that all growth parameters of wheat and lettuce was rising by rising nitrate levels to 50 mg L-1, but grain yield of wheat was non-significantly decrease at 50 mg L-1 with 3.52% decline comparison control. Furthermore, nitrate in lettuce wasn't harmful to human because nitrate didn't exceed the permissible limits. we concluded that it can irrigate wheat with water contain up to 20 mg L-1 NO3- without any decline in the grain yield, while in the lettuce plants, it can utilization water contain up to 50 mg L-1 without any harmful for consumers from nitrate accumulation in the leaf of lettuce. Where nitrate limits didn't exceed the permissible limits. This water is used with the recommended fertilization for both crops.