Diverse efforts are afoot to ensure smooth supply of drinking water to the maximum number of people around the world. As a result, the population supplied by piped water has also been going up. Demand will soon outstrip supply if effective measures are not taken to improve this situation. As population and demand for water increase, there has to be corresponding increase in reuse of wastewater too.

Reclamation of water for reuse can be one of the effective measures to bring about improvement in drinking water crisis. Research on practicability of water reuse has hastened in the past few decades. It was found that, in Israel, about 65% of wastewater is reused in rural areas while 23% is used in urban areas. Countries short of water may ultimately require sewers as a means of collecting all available wastewater for reclamation and reuse. Sewers can be a positive conservation measure and acute shortage of water in some countries has been mitigated by this method. Sewage, whether purely domestic in origin, industrial or agricultural, is the wastewater generated by a community. Domestic sewage consists of human excreta and wastewater resulting from washing, laundry and the cleaning purposes. Surface water sewers carry run-off from roofs, yards and roads. Sewers carrying only surface water can be discharged without treatment.

Research has made it clear that if sewage is discharged into a lake, stream or river, valuable nutrients are wasted. Not only this, the receiving water becomes polluted. As a lot of people still depend on surface water for irrigation and household water supply in hot climates, to retain quality of surface water, a realistic policy must be formulated on local pattern of surface water use.

Today, there has been an influx of people in the Kathmandu Valley due to the availability of various facilities relating to education, health, trade and commerce. This is why there has been a steady increase in water demand. Since water is the crying need of every individual it should be available to all. However an hour-long supply of Nepal Water Supply Corporation (NWSC) on alternative days will not be sufficient. Customers have got tired of complaining against NWSC as concerned authorities turn a deaf ear to their grievances. Although recycled wastewater is safe to drink, wastewater treatment and disposal systems are given low priority because of their high cost. Water supplies are continued without any provision for disposal of resulting wastewater. Apart from this, unavailability of an effective methodology to assess the relative value of refuse and professional biases of engineers, public health official and others, has resulted in scant progress. However, done effectively, wastewater reuse can reduce water problem in Kathmandu and other parts of Nepal.

Water reuse is a useful method for meeting water demand. However, such a method will only be successful if accepted by the concerned community. This is why community members should be involved in all stages of programming, planning and implementation.