Submersible diameter

my well pipe is 4” sch 40. From what I found, submersible pumps are about 3-7/8” in diameter. This is only 1/16” clearance per side. How can this possibly pull 12 GPM? What am I missing here?

 

If the 4 inch casing is steel, I think you would consider one of the slightly smaller diameter pumps, which are 3.75. These might be called Trimline, Slimline, or some such. The motor is 3.75 usually, but the pump can be bigger including the wire path.

The steel casing can have rust that can reduce the diameter in places. So it is not a matter of passing water, but avoiding the pump from getting stuck as it gets pulled. For more margin in steel casings, the 2.9 inch "3 inch" pumps are often suggested. I passed on that, and had my old Trimline put back after my pit was demolished and a pitless adapter was installed.

 

I've got plenty of 7.5HP pumps making close to 100 gpm in 4" wells....plenty of room.

 

Yes i have a handfull of 5 hp 75 gpm pumps in 4” casings that do almost 100 gpm