Need some clarifications regarding borewell pumping and discharge


I have a borewell of depth 175 feet, which has a 5 inch pvc casing for first 20 feet, 4inch pvc tube for another 145 feet with an overlap of 10 feet.

  1. What is the min/max safe distance to be maintained for the compressor head to pump out water from the borewell.
  2. Suggest a pump that is technically safe and easy to maintain
  3. What is the formula to calculte the delivery of water in 1 inch PVC tube for 30 minutes continuous pumping?
  4. What is the formlua to calcualte total volume of water present in 5 inch pvc tube for 1 feet?