Dear Sir

We have a submersible pump installed in our apartment premises ( garden area ) which is, however, the only water source. The pump has been running quite smoothly for the last 10 years. We are planning to install an additional submersible pump to ensure an undisrupted water supply, in case the first one stops working. I have the following questions:

1. What should be the minimum distance between the two submersible pumps? We can only install the second pump in the garden area because of the space constraint. Is 15 feet gap between the two pumps going to be okay?

 2. Since we are planning to install another pump on the premises of an already constructed building ( A stand-alone building ), should there be any distance between the building wall and the drilling point? 

Regards