Cost is deterrent to RWH adoption

Pop-up filter

City residents seem to be warming up to the mandatory rainwater-harvesting (RWH) proposal. A study by the Karnataka State Council for Science and Technology has found 51 per cent of RWH systems installed in houses meet the ‘minimum scientific requirement.’

As many as 21,720 houses have installed rainwater harvesting structures even as the Bangalore Water Supply and Sewerage Board is yet to come out with legislation rendering RWH mandatory. The study found only 50 per cent of such installations were working successfully.

Residents apprehensive

“Many residents are apprehensive about the cost involved in installing the system. The expenditure ranges from Rs 3,000 to Rs 30,000 depending on the requirement and the spot conditions. The system can be managed without any manual intervention,” said Shivakumar, the Principal Investigator, who led the study.

He said people should not fall prey to plumbers who quote low rates to install the system. “It is important not just to have an RWH system but also to install it scientifically to get maximum advantage and savings,” he added.

Choosing the right filter is an important aspect in the RWH system. The ‘pop-up filter’, which is normally available through the BWSSB plumbers, was designed at the KSCST which works effectively for residential buildings and smaller institutional or industrial applications. The cost of the filter ranges from Rs 3,000 to Rs 4,000.


The filter has three components — rainwater receptor, flush valve and filter element. Water received in the receptor flows upwards against gravity through a filter element to filter most of the floating elements and allow water to stabilise in this filtration zone.

Rainwater passing through this filter element (which is relatively cleaner) flows out through an outlet, which can be led to storage device.

Speaking to Deccan Herald, BWSSB chairman P B Ramamurthy said rainwater harvesting had become imperative since the second phase of Cauvery IV Stage would not slake the thirst of the burgeoning City.

He said the deadline for complying with the RWH guidelines will be issued soon with adequate time frame to install the structures.

Several banks have come forward to provide loans for installing RWH structures, he added.

The Karnataka State Council for Science and Technology is located at the Indian Institute of Science and can be contacted for all RWH-related issues.

For more information, call 2334 1652, 2334 8848, 2334 8849 or mail rwhkscst@vsnl. net or visit

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