Couple of days back we got a borewell drilled in our house at Rajendra Nagar, Hyderabad at a depth of 70 feet. Ours is a low lying area with plenty of underground water. It is so much that no house in our street has a proper water sump built without any water coming into the sump from outside.

After the drilling started, we found water at about 10-12 feet and never stopped from there till 70 feet depth. Casing is done for about 60 feet. Top 20 feet without holes and below 40 feet with holes.

During this drilling, loose soil/sand was coming out almost till 70 feet deep. Later, the driller started suggesting/saying that he would stop further drilling as there is lot of water (even in this summer) and also it may damage the casing. And, finally we stopped drilling at 70 feet. We can now see the water at around 2 feet from the top in the casing. We were able to touch the water with our hands.

After one day, I used our existing 0.5 hp motor to pump water from the borewell. It ran for couple of hours and I could hardly see any change in the water level in the casing.

My doubts are:
1. Is a 70 feet deep borewell sufficient enough, let's say for a single family.
2. As the top 20 feet casing doesn't have any holes, I'm assuming the water is getting stored from the below 40 feet casing which has holes. Am I correct?
3. When I'm able to pump water with a 0.5 hp motor, is it required for me to go for a submersible pump?
4. If submersible pump is required, at what depth should I place it?

Request you to clear my doubts.
Thanks in advance.
Regards,