How much will it cost
to catch rain?
When community come together to harvest rain, the per-capita
investment goes down. For instance, Panchsheel
Park Colony about 1000 residents pooled in
Rs 4.5 lakh to harvest more than 170 million litres of water
annually.
Rainwater harvesting methods are site specific and hence it
is difficult to give a generalised cost. But first of all,
the major components of a rainwater harvesting system - rain
and catchment area - are available free of cost. A good proportion
of the expenses would be for the pipe connections. By judiciously
fixing up the slopes of roofs and location of rainwater outlets,
this could be brought down considerably. However the cost
varies widely depending on the availability of existing structures
like wells and tanks which can be modified and used for water
harvesting.
Typically, installing a water harvesting system in a building
would cost between Rs 2,000 to 30,000 for buildings of about
300 sq. m. The cost estimate mentioned above is for an existing
building. For instance, water harvesting system in the CSE
building in Tughlakabad Institutional Area, Delhi, was set
up with an investment of Rs 30,000 whereas those in the model
projects ranged between Rs 70, 000 and Rs 8 lakh. The
costs would be comparatively less if the system were incorporated
during the construction of the building itself.
Some basic rates of construction activities and materials
have been given here, which may be helpful in calculating
the total cost of a structure. The list is not comprehensive
and contains only important activities meant to provide a
rough estimate of the cost.
a. Unit cost of construction
activities.
|
Item
|
Unit
|
Rate (Rs.)
|
| Excavation in soils |
cu. m. |
90.00 |
| Excavation in rock |
cu. m. |
150.00 |
| Brickwork with cement
mortar (1:6) |
cu. m. |
1400.00 |
| Plain cement concrete
(1:3:6) |
cu. m. |
1500.00 |
| Reinforced cement concrete
(1:2:4) cu. m. 4700.00Including steel bars, shuttering
etc. |
cu. m. |
4700.00 |
PVC piping for rainwater
pipes
- 110 mm diameter
- 200 mm diameter |
Metre
metre |
165.00
275.00 |
| Making borehole in metre
165.00Soft soil (with 150 mm diameter PVC casing) |
metre |
180.00 |
b. Ferrocement tanks with skeletal cage
|
|
Capacity of rooftop water harvesting
system in litres
|
|
5,000
|
6,000
|
7,000 |
9,000 |
10,000 |
| Total cost in rupees |
12,430 |
12,975 |
13,970 |
14,380 |
15,800 |
c. Plastic tanks:
Available as finished products in various capacities. The cost
of these tanks ranges from Rs 2/litre to about Rs 3.5/litre.
Other brands available in the market
|
Brand name
|
Unit cost (Rs. Per litre)
|
| Hindustan, Jindal |
1.80 |
| Storex, Ganga |
2.75 |
|
