Last summer I noticed water coming up from my basement, always in the same spot. The rest of the basement is bone dry and we have french drains so I was baffled. This winter, I tore up the tile that was in that area, and lo and behold, I found a hole roughly the size of a golf ball. I am not able to confirm whether this is where the water is coming from because nothing is leaking in winter, but this is the exact spot water always pooled from, so I assume it is groundwater coming up.

We are recent owners of the house, so I have no idea how the hole got there. I want to fill it. Someone warned me about water pressure building up if I did that, but there is a large sump hole very close to this.

Here are some pictures with my finger for scale:

image image

How do I fill this?

4 Answers 4


Your best bet is Hydraulic cement. There should be directions on the tin, but it boils down to clean the hole and fill it up. I'm partial to nitrile (or latex) gloves and stuffing it in by hand for something that size. The gloves because some people have skin reactions to cement; also you can throw the gloves away rather than rinsing cement down your drain.

If you do use your fingers to pack it in you'll still want a tool to flatten off the patch. Either a paint stirrer dragged sideways or putty knife should do nicely. It's not exactly the job you need a trowel for.

It sounds like you're right about the pressure, the water should migrate to the drain. If that hole was relieving enough pressure to buckle the floor I'd expect it to be gushing like you'd struck oil.


First I would wait until it is during your rain season so you can confirm that the hole is causing the issue. Unless you are facing some sort of water damage issues you might as well be sure what is going on and fix everything at once.

If it is just a small hole like yours I would just get a urethane repair kit like this one. This can be used wet/dry and performs better than epoxy alternatives.

  • 1
    I'm not sure that's the correct product for this situation. The manufacturer states "Suitable for sealing cracks ranging from 0.8 mm to 6.4 mm wide" . This is not a "crack", and is more that 1/4" wide. It's also not likely "seeping or mildly leaking". I personally haven't used this product, so I could be wrong, but it doesn't seem like it's designed to fill holes.
    – Tester101
    Commented Feb 13, 2017 at 12:25

i have similar but much large hole. it's about 12 sq in under the basement shower stall. In spring, water used to rise up. I wasn't sure if it could be filled. Instead I dug another hole in closet and installed a sump pump. Still looking for permanent solution. Maybe plugged both holes and force water back to the outside perimeter drain tiles.


I would dig a shallow well and install a sump pump and cover it with a grate or gravel.

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