Reusing this reject (wastewater) can help conserve water resources and reduce environmental impact. RO reject water is often best suited for non-potable applications. To know what is the perception of people towards RO reject water, the researcher conducted a descriptive study on the localities falling under Sharda Nagar of Lucknow. Based on the results obtained from the study, it was revealed that except EWS families, all types of LIG, MIG and HIG families use municipal water supplies as well as individual submersible pumps for water supplying, MIG and HIG households consume excess water for activities like plants, gardens, household washing, washing machines and vehicle washing which can be compensated by RO rejected water. But according to the data collected, only 33% of the households use RO. That is, in the houses where RO is installed, 270 litres of water is wasted in a month for the drinking water of one person. According to this, the amount of water wastage also increases depending on the number of the family.