Downspouts Draining Near the Foundation: What It Means on Your Home Inspection Report

Your inspector found one or more downspouts that empty at the base of the wall: no extension, an extension that's missing or disconnected, or a splash block out of place. Gutters collect the whole roof's rain and downspouts deliver it to a few points beside the house, so where each one ends matters.

The Department of Energy's Building America Solution Center notes that a few inches of rain on a roof can produce several thousand gallons of runoff. Left at the foundation, that water can quickly saturate the soil around the house and wick through the foundation to the inside, where it can lead to mold and rot.

Why It Matters

The Building Science Corporation's guide to foundation water says many foundation water problems start with drainage above ground and that this is the first place to look; its rule is that roof runoff must not be directed into the ground near the building. Water held against a foundation wall builds pressure that pushes it through joints and cracks, and the guide notes that where the wetting shows up inside, such as near a disconnected downspout, can point to the cause.

Soil raises the stakes. The Solution Center says gutters and downspouts are especially important where soils are expansive, which swell when wet and can push hard enough to crack a foundation, or collapsible, which shrink when wet and can let the ground sink under it.

What to Do Before Closing

• Ask which downspouts, and what was inside. Ask whether the basement or crawl space near them showed stains, damp walls, or white mineral deposits (see efflorescence).
• If downspouts run into buried pipes, ask where those pipes come out. The InterNACHI standards of practice don't require inspectors to inspect underground downspout drain pipes, so a clogged or broken one may not be in the report.
• If water has gotten in, have a drainage or waterproofing contractor evaluate it, and a licensed structural engineer if there are horizontal, displaced, growing, or wide foundation cracks, or a wall that bows.
• Talk to your real estate agent about asking the seller to repair or credit it within your inspection contingency. Extensions are a small fix; damage already done may not be.

What to Do After You Move In

Carry the water at least 5 feet out. The Solution Center's guidance, drawn from EPA's Indoor airPLUS program, is for downspouts to discharge onto ground that slopes away at least 5 feet from the foundation, or into an underground system, such as a dry well, at least 10 feet away. EPA's moisture-control guide for building design asks for more, sloped leaders reaching at least 10 feet, so farther is better where your yard allows. Codes can set a minimum too; the Solution Center notes that the 2018 International Residential Code requires roof water to be discharged at least 5 feet from the foundation, or to an approved drainage system, where expansive or collapsible soils are known to exist.

Where the water lands matters as much as how far: onto ground that keeps sloping away, not a low spot that drains back, with a splash block to control erosion. If the soil slopes toward the house, fix that too (see negative grading). And keep the gutters clear so water reaches the downspouts at all; our guide to cleaning gutters from the ground covers clearing a clogged downspout.

Buried downspout drains are a job for a drainage contractor. The Solution Center specifies non-perforated pipe running to a catchment system at least 10 feet from the foundation, a storm sewer, or another approved outlet, and warns that tying a downspout into the perforated foundation drain around the footing "will soak the foundation."

Can You Fix It Yourself?

Yes. This is a homeowner job:

1. Add an extension to each downspout that ends near the house, long enough to reach at least 5 feet out, and connect it firmly to the elbow at the bottom. The Solution Center's homeowner guide says extensions and splash blocks work "if they are connected" and send water onto a yard that slopes away from the house.
2. Set a splash block under the outlet so the water doesn't dig a hole.
3. Test it in the next good rain: the water should come out the end and keep moving away from the house.
4. Check after mowing and storms. The Solution Center notes that a 5-foot extension gets in the way of mowing. If you move one to mow, put it back.

Check your town's rules before sending water toward a sidewalk, street, or neighbor's yard. If you decide to bury a drain line yourself, contact 811 a few business days before digging and wait until every utility has responded, as the Common Ground Alliance advises for any digging; never connect the line to the foundation drain.

Frequently Asked Questions

How far should downspouts drain from the house?

At least 5 feet onto ground that slopes away, or 10 feet for an underground system, per the Building America Solution Center. EPA's design guidance uses 10 feet, so more is better.

Are underground downspout drains better than extensions?

They're out of the way, but you can't see them clog or crack, and home inspectors aren't required to check them. Done right, they use non-perforated pipe, end at a catchment at least 10 feet out or another approved outlet, and never tie into the foundation drain. If water backs up where the downspout enters the pipe, have a drainage contractor check it.

Is this a deal breaker?

Not by itself; extending downspouts is a small fix. If water has already reached the basement, or there are cracks or a bowing wall, get that evaluated before your contingency ends.

The Bottom Line

Downspouts that empty at the foundation put the roof's runoff exactly where you don't want it. Before closing, find out whether water has gotten in and talk to your agent about a repair or credit. After you move in, extend every downspout at least 5 feet onto ground that slopes away, keep the gutters clear, and leave buried drains to a pro. See more findings in our inspection report decoder.

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