TLDR: I have a 120V 1/4 HP general purpose motor with pump head attached (with female threaded connections for input and output). Could I keep this pump/motor above ground and run PVC from the pump head input to the bottom of a sump tank?

I have drainage issues in my unfinished, dirt-floor basement - it is so damp down there to the point that the red clay soil is ALWAYS damp unless we have >1-month of no rain. I have been converting this space to a workshop (drill press, mitre saw, dust collection, mini lathe, hydraulic press, and storage of wood/metal materials).

I'm thinking of installing a sump pump as part of a solution/prevention. I am also looking at the grading/slope around the house, drainage from roof, etc., but this question is specific to the sump pump. I have seen the pedestal vs. submersed sump pumps, but I have never seen a completely external sump pump and motor. I have several 120V motors with attached pump heads that I picked up extremely cheaply. The motors are 1/4 HP and they're rated at 18GPM (gallons-per-minute) I'd rather put one of these to use if I can rather than purchase a new pump. I am considering keeping the motor and pump above ground, with a section of piping running down to the bottom of the sump collection tank. Does this sound feasible? I can't seem to find anyone else doing this and was wondering why. I usually find people hacking almost anything into a solution.

The pumps I have are basically a lower-duty variation of this: The pumps I have are basically a lower-duty variation of this:

  • 1
    My guess as to why you don't see this more often is cost/complexity. You'll need a standalone float switch and a suitable screen/filter. If you have a plan for those I say go for it.
    – isherwood
    Jan 7, 2019 at 20:54
  • 3
    What is the dirty-water rating of the pump? Jan 7, 2019 at 21:06
  • As @Harper states, if there are solids in the water, e.g. bit of sand and clay, it will soon destroy water not designed for solids. Jan 8, 2019 at 0:47
  • Is the pump self priming? And what is the pumps ability to draw water from below. I have a fire pond that I fill from a drainage ditch I have to regularly prime the pump to get it going and because I am drawing water from 8' below the pump I need to prime it, the problem with the pump above is its really hard on the seals and I have had to replace them several times, you may only be a foot or 2 above but with a plastic housing if your pump deprimes it may over heat quickly and wipe out the housing.
    – Ed Beal
    Jan 8, 2019 at 14:21

2 Answers 2


Pumps where the pump mechanism (the impeller) is above the water line must be primed. So there is water in the impeller and no big airbubbles in the inlet pipe. If this is not the case then you can damage the pump.

You'll need a non-return valve at the inlet to prime it but if it leaks then you cannot keep the pump primed for any extended amount of time.

You could create a prime-on-demand mechanism where when you need to pump first a few gallons of water is used to prime the pump after which the pump can activate.

The cheaper solution is to run a shaft from the motor to the impeller (like a pedestal pump) or submerge the entire motor/pump. Only after taking precautions for waterproofing the wiring and ensuring adequate cooling.

  • That motor looks like a standard TEFC motor it would not work well even if sealed up because of the fan. Submersible motors don't have fans so that suggestion needs to be deleted.
    – Ed Beal
    Jan 8, 2019 at 16:53
  • If water wasn't an electrical problem it would be much better cooled than in plain air. However the bigger issue is waterproofing and preventing shocks and short circuits. Jan 8, 2019 at 17:10
  • The fan would be an issue even if sealed it would have to be removed.
    – Ed Beal
    Jan 8, 2019 at 17:33
  • Or replaced with something more optimized for liquid. Jan 9, 2019 at 1:46

The big questions I would be asking are.

  1. Will the pump damage itself if run dry?
  2. When running dry will the pump draw enough of a vaccum to self-prime.
  3. How well does the pump handle dirty water.

My feeling from looking at the pump in your picture is it won't handle these things very well.

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