I live in the area with substantial volumes of groundwater, so last summer I installed a sump pump in my garage, right in the corner of the garage. See illustration.

  1. Red circle is a sump pit, black line on the right is a discharge pipe
  2. Curved line outside of the blue rectangular is a drain pipe

I took a sump basin, and drilled a number of holes in the bottom and on the sides, wrapped the whole basin in landscaping fabric to prevent sand etc. entering the basin and clogging the pump, and installed it in the pit. So far the sump pump worked well. However, suddenly I noticed a seepage in the center of the garage (outlined on the figure), and it does not go away. Looks like somehow the groundwater found new ways and does not route in the sump basin anymore (although we're having dry weather these days).

I'm thinking to cut a "channel" from the basin across the seepage area (yellow line), cut out a concrete, and put drain slotted pipe in it so that it can accumulate ground waters, insert the end of it in the basin (there is side inlet available).

I was hoping that this should help. I would greatly appreciate any advice or suggestions!

The mystery remains why did the seepage suddenly occur in the middle of garage floor.

Garage layout

  • When making the pit, did you dig though concrete, quite a few inches of gravel/small stone and then dirt?
    – crip659
    Commented May 6 at 18:05
  • Your question is rather vague. Any number of solutions would do the job, including a simple surface cut. Please revise to ask something more specific.
    – isherwood
    Commented May 6 at 18:10
  • @crip659, yes I cut concrete, scooped out the gravel, and also had to break bed rock down below, to the depth of basin.
    – Mark
    Commented May 6 at 18:50
  • 1
    No, I mean it can give the water a path to the sump pail.
    – isherwood
    Commented May 6 at 18:59
  • 1
    The bedrock might be the reason. Depending on the shape, there might be a dip in the centre where water can collect, but not flow to the pit. They get the bedrock somewhat flat and use gravel to flatten it off.
    – crip659
    Commented May 6 at 19:08

1 Answer 1


As commented by @Isherwood, a saw groove cut into the surface will channel water from elsewhere on the surface to a sump, easily.

Simply sawing from one to the other will probably work. Making sure it slopes towards the sump will make it work better. Once in a while you may have to brush or wash collected dirt out of it to maintain flow, how often depending how much dirt gets onto the garage floor.

I have done exactly this to reduce several 2-3 foot wide puddles to 1/4" grooves leading to the sump in a basement. The groove was narrow enough that stepping on it didn't make your feet wet, and the former areas of puddle that had to be avoided or splashed through remained dry for the remainder of the time we had that house. Depending on inflow rate you might be fine with a 1/4" kerf, or you might need a wider blade to get sufficient flow.

  • thanks for feedback. In my case I don't have puddles of water on the floor, the cement floor is rather very damp and dark, it's almost that it is soaked through with the water (I might be able to make a photo and attach to this post). So, cutting a groove might not be a remedy for my situation, that's why I was thinking of something more radical (burying the drain pipe under the floor to collect water).
    – Mark
    Commented May 6 at 20:06
  • @Mark Having bedrock under the floor might make this more difficult. Some of the slab might be poured right on top of bedrock in some places, with gravel filling in the lower sections. Guess where the bedrock will be.
    – crip659
    Commented May 6 at 21:48
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    @Mark if they poured the floor without putting down a vapor barrier then moisture from the ground under the floor will come up through the concrete under certain conditions. I have an outbuilding where this happens when the weather changes. It dries out after a couple days. I say this since you said there isn’t actually any standing water but called it “seepage” good luck 🍀
    – ArchonOSX
    Commented May 6 at 23:05
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    It may behoove you to cut a french drain along your yellow line, and connect it to the sump pit.
    – Huesmann
    Commented May 7 at 13:22
  • @ArchonOSX, Thanks for comment. If this is seasonal phenomenon, what are the conditions this is occurring due? For example, cold weather changes to warm and humid? I wonder, how does weather change impact underground moisture? In this case, another option would be to have a dehumidifier draining water through clear plastic pipe in to sump pit.
    – Mark
    Commented May 8 at 2:29

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