Downspout Extension Ideas That Look Good and Work

A downspout extension should carry roof water at least 4-6 feet away from your foundation, and 6-10 feet is better. Beyond that distance, you can choose how it looks: buried pipe, a dry creek bed, a rain garden, a stone channel or a rain barrel.

The plastic splash block sitting in the dirt is rarely enough. It's very common, so don't feel bad if that's what your builder left you with. Here is how to replace it with something that works and looks intentional.

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How far should a downspout extend from the house?

Water that pools beside the foundation presses against the wall and finds its way through small cracks. The result is a damp basement or crawl space, and damp spaces invite mold. The goal is to move water past the backfill zone, the looser soil that was dug up when the foundation was built.

Aim for 4-6 feet at minimum. In clay soil, which drains slowly, I recommend going out to about 10 feet. The ground under the extension should also slope away from the house, roughly 6 inches of drop over the first 10 feet.

Skip the flexible ribbed pipe

Corrugated plastic pipe laid on the surface traps leaves and grit in its ridges, clogs easily and looks messy. Smooth-walled rigid PVC lets water flush debris out. If you have a dog that chews, a rigid pipe or a buried one is also harder to damage.

Should you bury the downspout extension?

Burying is the cleanest look, because there is nothing to see or trip over. The downspout connects to solid PVC pipe that runs underground, sloping gently, and ends at a pop-up emitter. The emitter sits flush with the lawn. Water pressure lifts the cap during rain, and it drops back down afterward so you can mow over it.

It also suits dogs. Nothing sits above ground to trip a running dog or to be chewed.

• Call 811 (in the US) or your local utility locator before you trench. Cable and internet lines can be shallow.
• Slope the pipe continuously downhill, about 1/8 to 1/4 inch per foot, so no water sits inside and freezes.
• Add a Y-fitting with a removable cap near the downspout so you can snake out a clog.
• Set the emitter on a bed of gravel and keep it lower than the house.

As an architect, I'd hire a licensed contractor if the run crosses a driveway, a septic area or anywhere near utilities.

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What if you can't trench? Try a dry creek bed

Tree roots or a tight budget can rule out burial. A dry creek bed is the usual answer. You dig a shallow swale leading away from the downspout and fill it with river stones of different sizes. It handles runoff and looks like a landscape feature even when it's dry.

Use smaller smooth stones for the base and a few larger boulders as accents, so the line looks natural instead of poured. Make it wide enough to read as a feature. A thin 6-inch strip looks stingy beside a house, while 18-24 inches looks deliberate.

One caution on weed control: Penn State Extension does not recommend plastic or synthetic landscape cloth on or under the soil, since it can increase erosion and water runoff. I'd skip the fabric liner and mulch around the edges instead.

Choose paw-friendly stone

Smooth, rounded river rock and flat flagstone are easier on paw pads than crushed gravel or lava rock, which have sharp edges. Let the swale drain fully within a day or so. Standing water breeds mosquitoes, and if your dog drinks from puddles, check with your vet about any health concerns.

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Can a rain garden take the water instead?

Yes. A rain garden is a shallow, planted depression that collects roof runoff and lets it soak in. Instead of piping water to the street, you extend the downspout to the bed. Choose plants that tolerate wet roots after storms and dry spells in between. Switchgrass, little bluestem, ferns and coneflowers are common choices.

If you share the yard with a pet, check every plant on your list against the ASPCA's toxic plant database before you buy. Keep the garden well away from the foundation, at least as far as the extension would have gone.

Which decorative above-ground options work?

When you can neither bury a pipe nor fit a wide creek bed, use a structured channel. A trench drain with a metal grate carries water across a patio or path and reads as a design detail. A splash path of slate or granite pavers, sloping away from the house, does the same job in a softer way.

Repeat a material you already have. Brick accents suggest brick pavers, and a modern concrete house suits a pre-cast concrete runnel. Heavy concrete or stone also stays put, unlike lightweight plastic splash blocks that shift in heavy rain.

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Is a rain barrel or cistern worth adding?

A barrel or cistern turns the downspout into a watering supply and keeps some runoff out of the yard. Slim galvanized or steel tanks hug a wall and take little space. A standard barrel looks better inside a wooden enclosure that matches your fence or deck. If you want a similar screening idea, see these breeze block wall ideas.

I recommend a closed system: a secure lid so children and small animals can't fall in, and fine mesh on the inlet to keep mosquitoes out. In freezing climates, disconnect the barrel in late autumn.

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Quick checklist before you start

• Walk the yard in the next heavy rain and see where the water actually goes.
• Check slope with a 4-foot level. The bubble should sit slightly off-center, tilted away from the house.
• Fasten the extension to the elbow with sheet metal screws so wind and kicks don't dislodge it.
• If your black window frames or copper fixtures stand out, match the extension finish so it blends in.
• Never connect a downspout to the perforated drain pipe around the footing. It overloads the system meant to keep the foundation dry.

Frequently asked questions