Despite of the abundances of water resources in Nepal it is facing crisis for the pure drinking water and water for irrigation and other purposes. The unmanaged utilization of the groundwater i.e. more extraction than the recharging has caused serious problem thereby reducing the ground level water. Conventional springs, dhunge dharas are going to dry due to these reasons and most time of the year there is dry or very low discharge in existing springs. This trend of water depletion is increasing year after year. It is due to concreting in the city, collection of rain runoff through drainage and discharge to rivers – reducing subsurface infiltration area. Existing natural flow runoff areas are occupied or destroyed by new infrastructures that caused change of surface runoff morphology. Therefore, rainwater harvesting is a prime means for solution of these problems.

Rainwater harvesting is a widely used term covering all those techniques whereby rain is intercepted and used ?close? to where it first reaches the earth. It means arrangements to cause rainfall to percolate the ground rather than run off its surface, to forms of flood control, to the construction of small reservoirs to capture run-off water so that it can be used for cattle or micro-irrigation and to the collection of run-off from roofs and other impermeable surfaces. Rainwater harvesting (RWH) primarily consists of the collection, storage and subsequent use of captured rainwater as either the principal or as a supplementary source of water. Both potable and non-potable applications are possible. 

Since the amount of the water that precipitates as rain only in the monsoon is sufficient for fulfilling the requirement of the people throughout the year, at the present situation of water problem in Nepal the project of rainwater harvesting has been Implementing in the major cities of the country specially in Kathmandu valley. The Kathmandu Metropolitan City (KMC) has given the major emphasis in this program and also has made different successful trials. Due to the easy establishment and long term benefits of it, it is growing widely. In the one hand the problem of the water is solved and reduced the pressure of water crisis and at other side it also helps in the economy as although the initial cost is a little bit more the long term effects of it leads to more beneficial than the present condition of buying water at higher cost. Many non-government organizations are also working in this sector for making the problem of pure drinking water solved permanently.

In the current condition of the increasing population in the Kathmandu Valley and increased construction works the only solution for the availability of the sufficient water supply is the Rainwater Harvesting. So, from the policy level to the ground root level the importance of the rainwater harvesting must be analyzed and proper coordination and collaboration must be done to solve the problem of water crisis of the country mainly in the city areas.