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I just bought a place. The basement was waterproofed by the last owner - a french drain installed under the basement floor around the perimeter, leading to a sump pump (done professionally, but no warranty I can take advantage of).

Naturally I was surprised when we had a heavy rain and I found a basement full of water. I was pretty sure I knew what happened, and when it happened again a week later, my suspicions were confirmed. The basement has three very low windows (the top of all three are at ground level) and with heavy-ish rain, all three window wells fill completely up. Two of the windows have been closed and sealed (looks like plywood was put over the window and then covered with concrete). A minuscule amount of water still seeps through one of these, but not a real problem. However, the one that is still a window ends up emptying itself into the basement.

The good news is that my property is sloped, and these are actually at the high point of my property. The bad news is that the surrounding yard (as well as part of my neighbors yard) slopes down to the house. So, the water already has somewhere to go. The issue is that it drains to the house and the runs along the house off of my property. If the rain is heavy, then some of it inevitably ends up in my window wells while it is working its way somewhere lower.

I can't decide if it would be better to build a simple "mound" running around this section of the house, so that it can't reach the actual house, or if it would be better to try to dig a drain. I suspect that something raised to divert the water would be easier - while the yard is sloped, it is gentle, so I might have to dig a long drain to get it to "empty" into a lower section of the yard.

Here is the side of the yard with the window that leaks. The water flows off "behind" me. The sandy area here is flat because there had previously been an above ground pool, but the yard rises to the left of the picture. You can actually see where the water was flowing towards the house (there is another "stream" that breaks off and flows directly behind me and down the yard without reaching to the house). A lot of water also comes down from the neighbors yard on the other side of the fence.

enter image description here

Here are the other two windows. These wells fill up, but the windows are fairly well sealed, so no water leaks into the basement. The ground right here has a more gentle slope, but it slopes towards the front of the house. Right around the corner of the house you can see that the yard drops off quickly (the front yard drains into a stream, and from there into a lake, so any water that gets into the front yard will be gone for my purposes).

enter image description here

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  • "Two of the windows have been closed and sealed (looks like plywood was put over the window and then covered with concrete)" This is a serious issue and prevents you from using the rooms they (used to) access as bedrooms.
    – FreeMan
    Jun 7 at 12:32

4 Answers 4

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I get the impression that you have a good handle on the problem and the potential solutions. I'm not sure we can make the decision for you from a couple of two-dimensional views. That said, I'd work the problem in this order, which basically lists solutions by effectiveness.

  1. Grade. Do as much as you can to manage and move water on the surface. Use soils that don't just pass water downward.
  2. Rain gutters. Be sure they're optimized and dumping in a sensible location. By reducing the volume load on the grade improvements you make they'll work better.
  3. Sub-drains. French drains and sumps are fallbacks to good surface water management, though they're often necessary where water tables are above footing level.
  4. Structural sealing. You already have a bunch of this and have witnessed its limitations. It's a last resort.

Good luck.

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  • Assuming I adjust the grading (maybe add a bit of a depression and a slope away from the house), how do I get that to "stay" in areas that don't grow grass well?
    – conman
    May 27 at 20:25
  • 1
    Landscape fabric and washed or crushed rock are a sure bet. Properly incorporated into your overall garden plan it can be quite attractive.
    – isherwood
    May 27 at 20:32
  • @conman - Can you figure out why grass doesn't grow well there? Is it lack of light, and/or something you could adjust with the soil, e.g. adjust the pH? If it's lack of light, could you do some pruning? May 29 at 1:14
  • @aparente001 It's light, and it's not going to change. There are 2 mature trees in this small area, and it's also heavily shaded by my house. It's the north side of the house and I'm at 40° Latitude, so I don't think it ever gets any sun (at least not the 6 feet closest to the house, which is where I need to work to redirect the water).
    – conman
    May 29 at 11:14
  • @conman - If you've already tried shade-loving grass, then maybe you could try a groundcover. Pachysandra maybe. But later on when you have time it might be worthwhile to check the pH -- if that's off, you could have problems with lots of things. I guess if you want to try a groundcover you could start with some small experiments before planting the whole area. May 29 at 21:44
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Had a similar problem at the back of my house.

Dug a couple of small channels and filled them with gravel, sloped them gently towards a handy drain. Worked well.

New owners are letting them grow over…

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  • Have you tried explaining how the system works, and what used to happen? Maybe they haven't figured it out. May 27 at 22:44
  • @aparente001 water flows downhill, at least it does where I live. Is it different for you?
    – Solar Mike
    May 27 at 22:51
  • Not everyone has thought carefully about drainage improvement projects. Why not give them a chance to learn how to maintain the system you made? May 27 at 23:20
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I had a similar problem. We discovered that the window wells had never been cleaned out over the years, and pea gravel had been used originally, so the water that collected in the window wells couldn't drain downwards. Note that our yard and our neighbors' form a very flat plain -- nothing to be done about that! We have mostly solved the problem as follows:

  1. We replaced the windows because the frames on the original ones were quite rusted.

  2. We dug out and removed the pea gravel and the eroded soil that was compacting the pea gravel. Here's how that went: we couldn't get a shovel into the reduced space very well, so we would loosen some soil/rocks with a pointy hand trowel, and then scoop the loosened material out with a round plastic take-out soup container. I, at least, did this by sitting on the ground with my feet in the window well, and leaning over to do the scooping. An audiobook or podcast helps. Three of us took turns.

  3. We made the window wells deeper by doing some extra digging.

  4. The metal semicircle was set in a bit too low down, but it would have been a major pain to replace it, so instead, we cut a piece of rigid (but capable of being bent into a curve) shower liner to just the right dimensions, and fit it just inside the metal semicircle, as a lining. We cut it taller than the original, so the top would stick out a couple of inches higher than the original metal semicircle had.

before adding the floor piece

In this photo, you can see that after doing the extra digging out, we put a bit of the pea gravel at the bottom to make the surface nicely horizontal. But we dumped most of the pea gravel somewhere else entirely.

  1. We also cut a floor piece out of the shower liner, drilled holes in it for drainage, and placed it in the bottom.

liner and floor in place

another angle

  1. We built up the soil level to meet the top of the shower liner -- remember, it sticks out a bit more than the original sheet metal did. Then we sprinkled grass seed and avoided walking on it for a while.

before building up soil level

Note the black milk crates, barely visible. Also note that the white thing at the top is the siding of the house. This photo was taken before we built up the soil level and planted grass.

  1. We didn't want to put a huge amount of rocks in the window well, so we jammed some plastic milk crates in for a tight fit, and then put rocks on top of, and around the edges, of the milk crates. We figured that the milk crates would maximize the pore space. Note that the top of the milk crates lies just below the bottom of the window.

Rocks: #2 River Rock from a big box store (comes in plastic bags our teenager is comfortable lifting), or bigger (we had a collection of rocks removed from the soil in various gardening projects).

  1. We bought a couple of extra downspouts and connected them to the bottom of our existing downspouts, horizontally (but slanted down a bit). We can kick each one over a couple of feet and then back when mowing the lawn. The idea here is for the gutters to dump their water 8 feet away from the edge of the house.

One window well got a slightly different treatment: when someone was here with asphalt to resurface our driveway, we had him build up a lip with asphalt in a semi-circle.

There are two more steps planned:

A. We are going to put a product that contains tar on the inside, because the heaviest rains do sometimes cause a bit of slow leaking at the bottom of the window.

B. We are going to make some repairs, or replace, some leaky gutters.

Looking at your photo: I guess you are planning on removing the dry leaves, and planting some shade-loving grass or ground cover? Good root systems are helpful.

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  • 1
    Thanks, I really appreciate all the suggestions! I'm accepting @isherwood's answer just because I know that grade and gutters are also a big part of my issue, but I'll definitely be taking plenty of your suggestions too!
    – conman
    May 31 at 21:20
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A dam/mound is probably easier, but has the unwanted effect of trapping water from the roof next to the house. If your gutters never overflow and wherever the downspouts go works, perhaps not a problem?

In my experience, the best solution is to make sure that the grade slopes away from the house by 1-2 inches over 8-10 feet.

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  • Unfortunately the gutter suck, but fixing those is on my list of things to do here. The gutters all go into drains under the ground so hopefully that actually goes somewhere helpful (I haven't figured it out yet)
    – conman
    May 27 at 20:16

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