Electrical resistivity survey results & evaluation in Chitradurga, Karnataka - Recommendations sought

I have undertaken an Electrical resistivity survey method for finding borewell points in my farm plot in Hiriyur Taluk, Chitrudurga District, Karnataka. My farm is located 15km before Hiriyur. I would like to know from the experts about the success rate (or dependability) of this method.

As per the report from Geologist the Land is completely covered over by hard and massive rock. One Bore point recommended in the depth of 300ft at gaps 220ft - 280ft - yielding 1 - 1 1/4inch of water. I wanted to get one more confirmation on this report.

In the neighboring lands (2 plots) 400mts away and other one is 450 mts away has 2 inches of water. Is there any other test which can give more accurate results. Please share your experience and advice. 

The Land can be seen from the url:http://wikimapia.org/#lat=13.8558827&lon=76.719085&z=16&l=0&m=a&v=2&search=javan agondana%20halli

In the name of <Javanagondana halli land> highlighted box.

Jagadish Babu