Water in Basement After Huge Storm: Is Our Retaining Wall to Blame?

LESLIE: Scott in South Dakota, you’ve got The Money Pit. What can we do for you today?

SCOTT: Approximately two weeks ago, we had a major thunderstorm down here. We got 8 inches of rain in 1 hour. We bought this house two, three months ago. Previous owners told us they never had rain in the basement – water in the basement. Well, in the front corner side, we got rain that came in the foundation, up and under the carpet. Not a little but not a lot. Enough to where we had to tear the carpet out and get rid of it.

And the front of the house is – we’ve got this landscape. Got a retaining block, like a landscape retaining wall, where they’ve got it graded level and bushes and stuff in there. I’m wondering – and that seemed to be the area where it came in at – first come into the basement. Is there something I can do? Do I have to tear that down and just keep it sloped away or …?

TOM: First of all, a couple of things. Because this happened when such a tremendous storm – I wonder if some of this might be covered by your homeowners insurance. So that’s one thing to look into if you’ve not done it yet. This is not sort of a normal occurrence; this is something that was more of a one-time occurrence brought on by, you know, 8 inches of rainfall. That weather pattern will be well documented. It might, in fact, be something that’s covered by homeowners insurance.

In terms of the solution, basements flood after rainstorms because of two things that usually go wrong with the drainage. Gutters are crucial to drainage. The gutter system has to be free-flowing and the downspouts have to be extended. If your home is susceptible to water in the basement, they need to be extended about 4 to 6 feet away from the house, minimum. Now, most of the time, gutters will be discharging within a foot or so of the foundation. And that water will just go, basically, from your roof right into your basement non-stop.

Now, the second thing that’s going to keep water outside where it belongs is proper grading. And as you mentioned, as you’ve described, when you have a retaining wall right in that sort of – we call the “backfill” zone around the house, where the house is originally excavated and then the soil was pushed back in against the foundation, then you build a retaining wall over that. You’re really preventing any drainage whatsoever from getting away from that wall.

And you’re right: fixing that is kind of a big deal because you have to take the retaining wall down or you have to improve the grading in some way to get it moving away. You may have to use some stone at the front edge of that so water can get through it.

What I would suggest to you is to work on the gutter system first. Because that causes most of the problems, in my experience. And then if you still have an ongoing issue, then deal with the drainage second. But fixing the gutter system is the easiest first step. Make sure that those downspouts are extended away from the house.

If you want to really do something on a permanent basis, you could run those downspouts underground through solid PVC pipe. Not the perforated kind but solid PVC pipe. And then break that out to grade somewhere or through a curve into the street, whatever is permitted by your local municipality. Or you could possibly go out solid for, say, 20 feet and then use perforated pipe in a stone trench and have it run back in the soil there when it’s well away from the house. But manage that roof water first and then worry about the drainage second, because that’s obviously much more difficult and more costly to correct.

Now, if you tackle those projects in that order, I think you’ll be good to go and pretty much flood-free. Thanks so much for calling us at 888-MONEY-PIT.