How Can I Fix a Leaky Basement?

Get DIY tips for keeping water and moisture out of your basement or ground floor. Plus learn a quick trick for determining whether your leaky basement is related to a rising water table, or simpler drainage issues.

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LESLIE: Hugo from Missouri, you’ve got The Money Pit. How can we help you today?

HUGO: I’ve got a leaky basement. Is there anything that can be done besides tearing up the whole outside and redoing it?

TOM: Yeah, that’s exactly not what you want to do.

So, the reason basements leak is because of drainage conditions that form at the foundation perimeter. So we’re talking about things like gutters that are overflowing or downspouts that are too close to the foundation perimeter or soil that’s sloping. Do you know – that’s sloping into the house or soil that’s flat.

Do you notice if this leakage gets worse after heavy rainfalls?

HUGO: Yes, that’s the only time it does leak is after a real heavy rainfall.

TOM: So that’s really good news because that means this has nothing to do with a rising water table. This has everything to do with the water that’s basically just forming around the foundation perimeter. And that’s something that’s fairly easy to deal with.

So, I want you to do a couple of things. Look carefully at the gutter system. You want to make sure that gutters exist, that the gutters have downspouts that discharge at least 4 to 6 feet from the foundation perimeter. And then you want to take a look and make sure that you have 1 downspout for every 600 to 800 square feet of roof surface. So just kind of stand back and try to estimate that in your head so we know you have enough downspouts.

HUGO: OK.

TOM: Now, typically, when they put downspouts in, they turn them out a foot or so and dump them into a splash block. And you’ll notice that that water will just sit right there and collect at the foundation perimeter. So you want to make sure they go out at least, like I said, 4 to 6 feet.

Now, the second thing is you also want to make sure that the soil at the foundation perimeter slopes away. If you have to add soil to do that, add clean fill dirt, tamp it down really super-well and make sure it drops about 6 inches over 4 feet. Those two things will stop your basement from leaking.

HUGO: OK. Thank you. I appreciate it.

TOM: You’re very welcome. Thanks so much for calling us at 888-MONEY-PIT.