Regarding the location of the borewell--> . I stay in a layout in Doddankeundi near Marthahalli and we have STP installed for sewage treatment.

I have dug a borewell with depth upto 400 ft.  We tried to clean up this borewell by blowing air and then also put PVC pipe up to the end of 400 ft and nearly 100 feet is without any opening.

When we took the water before putting the PVC pipes to a lab in  Bangalore for testing. They  told us after smelling the water that there is sewage contamination in  the water. At this point we didnt subject the water to any kind of test as they told us that the test will any how fail.

When we consulted one borewell guy he said he has treated similar things and can stop the problem by putting the PVC pipes. Now we have put the PVC pipes as he suggested with little bit stone gelly put in between the Casing pipe and PVC pipe.
After two days of pumping out the water for 3 to 4 hrs we still see that the foul smell is there. When we get the water it looks clean but after 12 hrs or so it will turn slightly yellow color.

We have few more borwells in our layout but none have this kind of problem. There is no near by septic tanks or any other things which can contaminate this. Only suspicion for me is the near by lake across the railway track which is around 1 to 1.5 km away from our area. But probably our area also would have been part of the lake bed and would have got separated from it after the railway line was laid.

It is a low lying area as well and there is always some kind of ground water present in this area. So the other doubt is of ground water creeping in to the borewell. Borewell has got plenty of water. But now after putting the PVC pipe the smell is substantially reduced but the color gets changed to slight yellow after 3 to 5 hours.

Could any one help find what exactly is wrong here?

Mansoor
kpmansoor@yahoo.com