Outside the house: grading, downspouts and window wells

There is an unglamorous truth underneath a large share of wet basements: the house is collecting rain off a large roof, concentrating it into a few downspouts, and then putting it on the ground right next to the foundation. Then the ground, which has settled over the years into a gentle slope toward the building, delivers it to the wall.

Three things account for most of it. Grading: the soil around a house should fall away from the walls for the first several feet. Backfill settles over time, planting beds get built up, patios get added, and what started out sloping away ends up sloping back. Downspout discharge: a downspout that ends at the foundation, or into a short splash block, is a concentrated stream of water arriving exactly where you least want it — extensions or buried lines that carry it well clear are the single highest-value change available in this whole subject. Window wells: a well below grade is a bucket. If it has no working drain, or the drain has silted up, it fills during a storm and then the water is at the window, which is the least waterproof thing in the wall.

Beyond those, the yard itself sometimes needs help. Standing water that sits for a day after rain means the ground isn't accepting or shedding it, and the remedies — a swale that redirects surface flow, a dry well that gives it somewhere to sit, a catch basin at a low point — belong to landscape drainage rather than to the basement, even though the symptom shows up indoors.

None of this is exotic, and much of it is genuinely within reach of a homeowner with a shovel and a level. That is the reason this section exists at all: it is the work most likely to be skipped in favor of something expensive happening inside, and it is frequently the work that would have solved the problem. If it doesn't solve it, you have lost very little and learned something useful — the water isn't coming from the surface.

Sources

What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.

• US EPA. What You Can Do to Soak Up the Rain
• US EPA. Soak Up the Rain — managing stormwater around a property