Cost of rainwater harvesting system varies widely depending upon the availability of the existing structure of roof and storage tank. Cost also depends upon the material used in it. The cost of RWHS can be minimised by using such ready structures. To minimise cost it is advisable to incorporate RWHS during construction of the building. The cost of gutter, conduit pipe, down pipe and filter varies from Rs 1000 to 4000 per unit. Major cost component in RWHS is of storage unit which ranges from Rs 1.5 to 2 per litre capacity should be preferred for harvesting rainwater from couple of residential units in the same colony. The cost of RWHS with standard specifications for meeting the needs of an average size residential unit having storage capacity of 10,000 litres works out to be approximately Rs 20,000. To popularise the concept of RWHS, Government and NGO’s provide financial and other aid to the beneficiary. Hence actual cost to the beneficiary of RWHS is substantially reduced.
Cost Benefit Analysis of Rainwater Harvesting Structure
There is no operational cost in the RWHS and only initial investment needs to be considered. There is no consumption of energy in RWHS. It makes available safe potable water at doorstep of the beneficiary. It involves the beneficiary in maintenance of RWHS. It relieves women and children from drudgery of bringing water from external sources. It enables them to continue their preoccupation and/or gainful employment. RWHS not only relieves the beneficiaries from water stress, but it also relieves local authorities /Government. When domestic water security is available from RWHS, Government can continue its developmental activities instead incurring heavy spending on temporary measures for providing water security. RWHS augments the resources whereas other means of water supply depletes the resource from which water is obtained. Benefit of RWHS is available for long term without spending any amount later on while other means of supply needs recurring expenditure from year to year. RWHS inculcates habit of judicious use of water as beneficiary is directly associated with it whereas other modes of water supply make beneficiary careless. Considering the tangible and intangible benefits along with that of assured delivery of safe potable water of approximately 10,000 litres or more per year, the one time investment in domestic rainwater harvesting system is worth.
It is only through the community initiatives that we can reduce the gap of demand and supply of water. Water is too serious an issue to be left solely to the government.
As per UNDP report one third of the world’s population is living under moderate or severe water stress. By year 2025 nearly two-thirds of the world population may experience moderate and severe water stress. Each year, 25 million people die from disease caused by unsafe drinking water.
Rainwater Harvesting can certainly provide relief to the class of beneficiary from water stress. However this is not enough as rainfall ultimately depends upon global ecology and environment, which we have spoiled.
Let us firmly resolve not only to protect and preserve our natural resources and ecology but also do our best to improve it so as to save mankind.
(The writer is former Minister of State for HRD, Health, Heavy Industry, Government of India.)