Reducing water and electricity

Rain water harvesting

We have a 20,000 litre tank which should reduce our consumption of municipal water to half, given Bangalore’s rainfall pattern. If this works as designed, we’ll add more capacity to become fully self-sufficient in water.

Rain water sump

Rain water sump - inside

We have had a lot of people telling us that harvested water was not potable and was bad for the health; that we must have two separate sumps, one for the harvested water and one for water from the city’s supply. The former must only be used for gardening, and the latter for use in the home.

We got two samples of water tested, one from the sump and one after the water purifier (an Aquaguard Classic with a UV filter), and found that:
1. Chemical impurities in the sump water were well below limits permissible for drinking water, while bacteria were more than permissible limits.
2. The water from the purifier is bacteria-free, fit for drinking. It bumped off ALL the bacteria.

Conclusion : Water from rain water harvesting is perfectly OK for any use. Just filter it through a simple UV filter.

A UV filter bumps off bacteria by Ultra violet rays – see Our filter we bought second hand 6 years ago for Rs. 2500, and we pay Rs. 800 a year for annual maintenance charges.

See the test reports:
Water-test-Oct-2011-Sump : Water straight from the sump.
Water-test-Oct-2011-Filtered  : The same sump water, after going through the filter.
In each report, the first page is chemical characteristics and the second is the bacteriological characteristics.

Gray water harvesting

The bath and wash basin water from 2 second floor toilets goes into a loft tank, is used for the garden. We also used to pipe it to the first floor toilet’s commode, but even the mild soap in it caused bacterial action, turned the water black and smelly as it was stored in the loft tank. Looking for a solution to this problem so we can start doing this again.

Solar water heater
We have a 200 l. capacity solar water heater that does its job beautifully. It has an inbuilt heating coil for cloudy days.

Water testing (Costs approx. Rs. 1300 per sample) : Essen & Co., Malleswaram. Ph : 23341230 / 23341567

  1. November 17, 2011 at 9:54 pm

    This is wonderful, Das! So inspiring!

  2. R
    September 20, 2013 at 11:19 am

    The area I live in, we get only hard water to drink. I’ve been wondering if it’s harmful in the long run, to use hard water after a simple pure it filtering…If it’s not such a good idea, is there a water purifier that does not reject too much water during the softening process? I won’t be able to set up a system reuse huge amounts of ‘rejected’ hard water, which is why I am particular about this.

    • September 21, 2013 at 6:58 pm

      As far as I know, hard water is not harmful to the health. It is only water that is high in mineral salts – of Calcium and Magnesium. It causes scaling in equipment through which it passes.

      A water softener, according to this site, adds replaces the Ca and Mg with Sodium that is bad if you have hypertension.

      We just use the old style Aquaguard UV filter in our home. See the test results for the water from this filter, on this page.

  3. November 19, 2014 at 12:11 pm

    You can try a bio / bacteria based water purifying agent. We did try a sample at our place and the smell went down considerably.

  4. Ashraf
    March 26, 2018 at 5:02 am

    Any contacts details for implementing rainwater harvesting in Mangalore ?

    • March 26, 2018 at 7:55 am

      Some options:
      1. Most house building contractors now have capability to implement rainwater harvesting systems. It’s not a complicated thing.
      2. As you’re passing by homes, if you see a nicely done system you can just go and ring the doorbell, ask for contact details of the person who did it. I do this often, and am quite shameless about it :).
      3. You can call these people, ask them if they know someone in Mangalore.

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