My son just got water in his basement from some water coming in through some small pipes (not copper) that protrude from his basement wall. I have never seen something like this before.

Picture of pipe through basement wall

The pipe is about 2 ft above the basement floor. The larger pipe sitting on top of the small pipe in question is the supply line for their steam heat and was not part of the problem. It is a 1920's vintage home on the East Coast. They were having heavy rains that have saturated the ground. There are three of these pipes spaced across the wall that is at the front of the house.

At some point, water started coming in through 2 of the pipes (the 3rd pipe appears to be sealed with caulk or something). The water was a steady flow, not just a trickle but it was low pressure. You could stop the flow with a finger and they were able to stop the flow by stuffing a rag into the pipe. I am pretty sure it was ground water coming in. They have been in the house for 3 years and this has never happened before and the previous owners had never mentioned this. The ground was already saturated and they were having heaving rains from the remnants of Hurricane Ida.

  • Does anyone have any ideas what these pipes might have been there for? They appear to have no current function.
  • Is it safe to seal these up and if so with what?

3 Answers 3


The arrangement of the pipes (3 @ equal spacing 2' above the floor) indicates these are groundwater relief holes (weep holes) for releasing the excessive hydrostatic pressure caused by fast-rising groundwater during the rainy season. Your normal groundwater should be way below the pipes, thus most of the time they will be dry.

Do not plug them, the wall wasn't designed for elevated water pressure from outside. It is advisable to install a sump pump in the basement near the wall and have scattered floor drains and embedded pipes to divert the water towards the sump pit.

ADD: Another cheaper way to do this is by connecting the pipes to a larger drain pipe that releases the water at a convenient drain point.

  • Interesting -- so "back in the day" dumping water into the basement was considered acceptable? But anyway, I would have someone inspect to see if there's already a B-dry or similar system in place, in which case these pipes are obsolete and can be plugged up. Sep 2, 2021 at 17:25
  • TBH, this was my first thought, though I'm far from an expert on foundation drainage. Considering that there had been no water seepage until the heavy rains, this seems to be a reasonable assessment.
    – FreeMan
    Sep 2, 2021 at 17:53
  • Per the design assumption, these pipes shall be dry most of the time but to add extra safety to the wall in case a flood occurs (a calculated rare event). However, after years, the groundwater elevation may have changed/risen, thus causing constant flow. Also, unless your son is the original owner, he might not aware that the previous owner had installed the pipes to solve the very same issue - excessive pressure on the wall.
    – r13
    Sep 2, 2021 at 17:53
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    @CarlWitthoft as a failure mode minor flooding is preferable to the wall caving in. And when dirt floored basements were still common being a bit damp wouldn't be considered abnormal. Stronger/thicker walls would be a better solution, but could be significantly more expensive. Sep 2, 2021 at 21:07

I have the same pipes in my basement, they are for groundwater drainage overflows. I joined them together into a larger 2" pipe running into a container, I used a garden rainwater butt, and put a float operated pump inside to automatically empty the butt when it fills up. No problems with it for last 5 year, fills the butt 2 - 3 times a year.


The small pipe looks like it is used as just a support for the bigger pipe. It might go though most or all of the wall and ground water is finding a way in.

Usually the best way to seal something like is from the outside by digging down to the problem area and sealing.

Most inside sealing usually does not last too long, but is okay for temporary fixes till permanent fix can be made.

  • hydraulic cement should seal those leaks from the inside just fine. Clear out gunk and any sealant first. Sep 2, 2021 at 17:23

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