Need solutions for treating the borewell water


I have started a residential project in Malleshwaram Bangalore. On 6th November 2013 we dug a borewell and were luccky to get good water. At 200 ft in rock we got 1 Inch. We continued to drill till 490 feet and got 1.74 Inch to 2. inches.

Now the question is, for 1st 75 feet it was silt. We got rock at 80 feet, we have done casing till 80 feet. Now I doubt if the water will be good for drinking. Should I put clay pebbles?

Also please suggest a good motor with capacity specifications to pump water to the over head tank which will be placed at 65 feet above the ground level.