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Clearance Inside The Well

The well drilling community started using pitless adapters in the 60s and 70s.  Some of the early designs do not allow enough clearance to install any kind of additional pump.  It seems as though everyone started to use a “normal” or "slide"  pitless adapter (below) after 1990. Slide Pitless adapters push all the pipe to one side of the well casing and create a gap on the opposite side.  It is through this gap that we install our pump


Removing the cap (easy) and visually inspecting what type of pitless adapter you have is the first step.  .


Slide style pitless adapters

These pitless adapters are good

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If you see any of the the following, go to the “Weird Wells” tab.  These pitless adapters are Abby Normal

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Pitless with support bar

Common in Michigan


Snappy pitless adpater

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This is an "in well pressure tank" used for mobile homes

If the Inner diameter of your casing is 6-1/4 (normal) and you can visually determine that you have atleast a 2 inch gap, then you can install every one of our pumps, clearance is not an issue.  But if there is a question about if our pumps will fit through the gap in side your well then the following clearance test should be performed.   The clearance we are looking for is the distance between the pitless and the opposite wall of the casing or any other obstruction inside the well.  Can one of our pumps slip through the gap and get to the water? There are three gaps

the gap.jpg

Please note pipe sizes are tricky, they are “trade size”. Do not use a tape measure to determine pipe size use the markings on the pipe!

Gap                  PVC Pipe*        Compatible Pumps


1.90"+                  1-1/2”                    AK, AR, SJ

1.66-1.89”            1-1/4”                    AR, SJ

1.32-1.65”            3/4" with cap         SJ

* Trade size 

The Test

Our three pumps are manufactured out of high quality PVC pipe.  This pipe has no markings on it but is dimensionally identical to PVC pipe found in hardware stores across America.  If there is any question about clearance simply purchase a 10ft stick of PVC pipe in either 1-1/2, 1-1/4 or 3/4” (with cap) and see if you can slip it past the pitless adapter or other obstruction in the well as per the above Table. 

If you can slip a 1-1/2 inch PVC pipe into the gap then you have a gap of at least 1.9 inches and can install any of our pumps

If you can only slip a 3/4 inch PVC pipe with a cap or other fitting glued on the end, through the gap, then you can only install a SJ pump.  The outer diameter of the SJ pump is actually smaller than the outer diameter of the threaded adapters glued onto our drop pipes, so this is why we use a fitting for the clearance test instead of pipe.


In extremely tight situations the threaded adaptes can be filed or ground down on opposite sides to fit past an obstruction.  The test should be repeated with 1" PVC pipe as this represents the outer diameter of our SJ pump.  The outer diameter of the SJ pump can not be modified to fit past the obstruction.  If 1 inch PVC pipe can not clear the obstruction then got to weird wells tab.


In most 6 inch wells with a normal pitless adapter clearance is not a problem, but if  internal clearance is reduced another pump model may be selected that requires a smaller gap.  If this is the case consider an AR or SJ pump for your well.

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