GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Installing an Exterior Sump Pump

drewintoledo | Posted in General Questions on

Hi guys. New build soon. I’m going to install an interior sump but I also would like to implement an exterior sump but I’m unsure how to place it.

My first thought says stand a culvert pipe on end and drop a sump down to the bottom, but I’m hopeful others with experience have a real world example of how to install such an idea they can share?
thank you.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Expert Member
    BILL WICHERS | | #1

    The easiest way to do it is to get a precast manhole or storm drain assemly and use that. All you'll have to do is core a few holes in the sides for plumbing and electrical lines and you're good to go. You can get solid or grate (drain type) lids too. Easy and quick (relatively :-)


  2. walta100 | | #2

    How do we insure the pump will not freeze?

    Where will it discharge to?

    Will it have an alarm circuit to signal you should the pump fail?


    1. Expert Member
      BILL WICHERS | | #3

      As long as the sump pit is deep enough, it won’t freeze. If you look down a storm drain in winter, you’ll find the water in the bottom of the deeper drains isn’t frozen.

      A high level alarm to indicate pump failure is a good idea.


    2. drewintoledo | | #4

      Frost line here is about 40” and this pump will sit more than 120” into the abyss with a cover over the entrance.
      Hello Walter. Plans are to discharge the pump into the culvert where the other sump and rain runoff will empty. I’ll definitely have an alarm system. This exterior pump is “primary” sump, I’ll have another in a crock in the basement at a higher set point as the exterior pump and will have an alarm as well.
      I’m in a wet area. It never made sense why convention says channel perimeter water under the floor and into the house only to mitigate and pump it back outside.

      1. Expert Member
        BILL WICHERS | | #5

        If you go with a precast manhole, you'll get all the fun of dealing with the manhole cover -- which is about 150 pounds or so of cast iron. Get yourself a "manhole hook" to make things easier. All a manhole hook is is a handle with a curved hook on one end that you can slip into the lift slots/holes and lever the manhole cover up off the ring in the manhole so that you can slide the cover off. It's not super difficult once you've done it a few times. You can buy manhole hooks, or just make your own. I made mine a long time ago from a length of steel rod that I bent on my metal bender. Most manhole hooks are made from steel rod around 5/8" diameter or so. I wouldn't go smaller than about 1/2" or it will bend too much when you use it.


  3. Expert Member


    Out here we often do as you suggest, using a culvert with slits or holes cut in the sides. It works well, but we don't have frost heave, and I wonder whether the corrugations might cause problems in colder climates? Maybe the surrounding drain-rock insulates it from that?

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |