Lemongrass (Cymbopogon flexuosus) essential oil yield and quality were evaluated in a field experiment conducted at ICAR-Indian Agricultural Research Institute (IARI) to evaluate the effects of groundwater (GW), untreated wastewater (WW), constructed wetland treated wastewater (TWW) and groundwater in conjunction with untreated wastewater in cyclic mode (CW) in the main plots and three levels of fertilizers in subplots viz. control (no NPK fertilizer application)(N 0 ), the recommended dose of NPK fertilizersthe amount of NPK added through irrigation water (N 1 ) and recommended dose of NPK fertilizers (N 2 ) during 2018-2019.The trial was arranged in a split-plot design with three replications.The total oil yield from three harvests was the maximum (546 L ha -1 ) in the case of wastewater irrigation and the minimum in the case of groundwater (476 L ha -1 ). Irrigation with untreated wastewater resulted in significant increase of 11 and 16% in essential oil yield compared to treated wastewater and groundwater irrigation, respectively. The total oil yield from alternative irrigation with wastewater and groundwater was equal to that obtained in the case of irrigation with treated or untreated wastewater. The neral (neral is an isomer of citral i.e. the major compound in the lemongrass oil) and geranial contents obtained from groundwater and treated wastewater irrigation were 11-14% higher compared to alternative irrigations with untreated sewage and groundwater. Overall results indicated that the wastewater can be used for growing lemongrass aromatic crop to produce essential oils without causing any reduction in quantity and quality.