Sri Lanka

Estimated materials and costs for a 5 m³ ferrocement and brick tank.
(Source: H. Heijnen and U. Mansur, 1998)

The picture below shows a typical Sri Lankan "pumpkin" tank und construction (reinforcement).

Kenya

Materials and costs for a 6 m³ ferrocement tank. Diameter: 2.00m, Height: 2.00m

 

		Material	unit	total
		3 tons sand	1000	3000
		1 ton course aggregate	600	600
		10 50kg bags cement	500	5000
		10 m BRC	280	2800
		4 tons hard-core	300	1200
		10 m chicken wire	100	1000
		5 kg binding wire	100	500
		1 pipe fitting	700	700
		10 gunny bags	50	500
		2 kg sisal twin	100	200
		3 m polythene sheet	100	300
		5 gutters, overshooting guards	500	2500
		10 offcuts	20	200
		1 manhole cover	200	200
		7 mandays labour skilled	200	1400
		21 mandays labour unskilled	70	1470
		Total		22070

Be careful: Cost of tanks includes labour, guttering and transport of materials.
Prices are given in Kenya Shillings (KSh, Feb. 1999, 62 KSh = 1 USD)

The picture below shows the tank being plastered.

Ghana

Rainwater tanks for households have been introduced to Northern Ghana in April 2005. First costings came to a price of USD 550,- for a 10 m³ tank, inclusive of gutters, see table of materials below. After some experience, the price might go down.

Item	Description	Unit	Ferrocement tank
1	Building river Sand	m.tons	7
2	Weldmesh 8ftx4ft	pcs	13
3	BRC fabricated	R 6	-
4	Chicken wire	3ft roll	-
5	Gravel	7 ton Lorry	0.25
6	Cement	50kg bags	20
7	Sugar bags	Empty	10
8	Pipe take off	Pipe system	1
9	Manhole cover	Fabricated locally	1
10	PVC /GI ladder	Locally assembled	1
11	Polythene sheet	Meter.	6
12	Gutters	pcs	6
13	White wash	25kg bags	1
14	Inlet bucket	PCS	1

The picture below shows the ready-built tank

This is the rural rooftop rainwater harvesting scheme inspired by the Chinese 121 programme and the Brazilian 1 million cisterns programme in progress in Karnataka, India.

Here each drought hit village house gets a 2500 litre rainwater tank usually made out of brick masonary by the village mason using materials from villages. It is expected that the tank can collect between 10,000 litres to 20,000 litres of water in a year from the 25 to 40 square metre roof area catchment. This would of course depend on the rainfall which varies from 400 mm to 800 mm and its distribution too.

The single biggest jump was made by using the rainwater tank as a multipurpose tank. The household can source alternate water whether from tankers or wells or bore wells or even by bringing it from ponds and lakes whenever possible and filling the rainwater tank and using it as a store.

In this case when a multipurpose tank is made available it is possible for them to stock water once in 10 to 15 days and use it whenever they need. The psychological security of stored water is much appreciated by the women.

Only a small section use rooftop rainwater for drinking and cooking but the numbers grow. The roof is mostly Asbestos cement sheets and in some case tiles. The gutters are of PVC. A first rain seperator is provided as is a sand filter with about 75 mm of sand in a GI funnel.

The cost of each unit is Rs 5000 /- approx116 US$ per family.

Approximately 3500 such tanks have been built. Another 20,000 will be built this year and overall 400,000 units will be built in the 21,000 drought affected habitations of Karnataka state in the coming years.

S.Vishwanath (www.rainwaterclub.org)

   / rainwater harvesting / Toolkit: / Socio-economic and health aspects / Cost implications / Examples from different countries