How to Route Downspouts Away From Your House

Why You Should Route Downspouts Away From Your House

A single downspout can carry a surprising amount of water — a modest roof area sheds hundreds of gallons in just one inch of rain. If that water discharges right at the base of the wall instead of well away from it, it saturates the soil exactly where you don't want it, contributing to foundation moisture, basement dampness, and erosion. Fixing this is one of the cheapest, easiest corrections in home maintenance, and it solves a disproportionate share of foundation water problems for the effort involved.

How to Route Downspouts Away From Your House

1. Inspect the existing drainage. Check where each downspout currently discharges. If it's within a couple of feet of the foundation, or ending in a spot that slopes back toward the house, that's the problem to fix first.

2. Add a downspout extension. The simplest fix — a rigid or flexible extension attached to the bottom of the downspout that carries water further from the wall before it discharges.

3. Use a splash block, but don't rely on it alone. A splash block helps spread water out and reduce erosion at the discharge point, but it doesn't move water very far. It works best paired with an extension or proper grading, not as a standalone fix.

4. Route water across a sloping yard. If your yard naturally slopes away from the house, a simple extension discharging onto that slope may be all you need — the grade does the rest of the work.

5. Install underground drainage. Where a visible extension isn't practical or the yard doesn't slope enough, a buried pipe can carry water discreetly to a discharge point farther from the house.

6. Consider a rain garden or suitable landscaped area. In the right location, downspout water can be directed into a planted, well-draining area designed to absorb runoff — though this isn't appropriate for every yard or soil type.

How Far Should a Downspout Be From the House?

General guidance points to discharging water at least 5 feet from the foundation on a sloping grade. If you're routing water to an underground catchment system instead, that system should be located at least 10 feet from the foundation, and shouldn't be connected to your home's foundation drain. Where your yard doesn't have room for that distance, an underground line or catchment system becomes the more practical option over a short surface extension.

How to Route Downspouts Underground

Burying a downspout line keeps the yard clear while still moving water where it needs to go:

1. Connect the downspout to solid, non-perforated drainage pipe — not the perforated pipe used for a foundation drain

2. Route the pipe to a discharge point at least 10 feet from the foundation

3. Make sure the pipe maintains a consistent slope along its run so water doesn't pool or reverse direction inside it

4. Terminate at daylight, onto a properly sloped area, or into an approved catchment system

5. Don't connect it to your home's foundation drain system — mixing the two can overload the foundation drain and undermine the whole system

Where Should Downspouts Drain?

Reasonable discharge locations include a sloping lawn area, a landscaped bed that drains well, an underground catchment system, or an approved storm drainage connection where local rules allow it. What matters most isn't just the distance — it's what happens to the water after it's discharged. An extension that dumps water into a low spot, a depression, or an area that slopes back toward the house doesn't actually solve anything; it just moves the puddle a few feet. Check local regulations before connecting downspout drainage to a storm sewer or sanitary sewer system, since this isn't universally permitted.

Common Downspout Drainage Mistakes

• Using a short extension that still discharges within a few feet of the foundation
• Relying on a splash block alone without checking whether the surrounding grade slopes away
• Discharging into a spot that's already low or slopes back toward the house
• Connecting a downspout directly into a perforated foundation drain pipe
• Burying a line without confirming it maintains a proper slope along its length
• Never testing an underground drain to confirm it's actually flowing

How to Tell if Your Downspout Is Still Causing Foundation Problems

Check the area near each downspout during or right after a rainstorm. Signs the current setup isn't working include standing water near the foundation, visible erosion or a washed-out channel at the discharge point, and soil that stays soggy well after the rest of the yard has dried. If you see these even after adding an extension, the issue is usually the discharge location, not the extension itself — it needs to end somewhere that actually drains, not just somewhere farther away.

When to Call a Professional

• Your yard doesn't have enough slope or room to achieve proper distance from the foundation and you're considering underground drainage
• You're unsure whether local regulations allow connecting downspout drainage to a storm or sanitary sewer
• Water problems persist even after extensions and grading corrections
• You're planning to combine downspout drainage with a French drain or broader foundation drainage system and want the design coordinated correctly

Last updated August 2026. Found something outdated? Let us know.