Our pumps need a 1-3/4" clearance inside the well casing. Most wells can easily accommodate this. But know that you may need to slightly lift, twist, wiggle and worm the Gunslinger pump and its flexible tubing around your current water pipe and/or electrical lines to get the pump assembly to hang freely inside your well. Refer to the instructions for more hints and tips regarding its installation. Most modern wells are fitted with a pitless adapter. In some narrow well casings, the bulk of the adapter may present a challenge to get the Gunslinger pump to pass by and clear the obstruction. We found this outstanding article, written several years ago and posted on Instructables.com, that outlines the procedures to remove and replace a submersible well pump. You do not need to go through this entire process. But the article describes in detail how to raise the pump assembly, out of the pitless adapter's bracket, which is attached to the well casing. By raising the assembly just high enough to clear the well head (usually 4ft. or less), you can then insert the Gunslinger pump and flexible pipe into your well, and lower it to the proper depth. Then simply set your well pipe's pitless adapter back into its bracket. The article itself is extremely informative for anyone who has a submersible pump. If you ever need to replace your existing pump, having this information available could save you thousands of dollars that you might otherwise spend with a well drilling or repair service. It also has vital information on sanitizing your well, to prevent contamination. Here's a link to the article: https://www.instructables.com/How-to-Replace-a-Submerged-Well-Pump/ And here is a link to the downloadable pdf file of that article: How to Replace a Submersible Well Pump