How do I know if my downspout is clogged?

The gutter overflows near the outlet, little water comes out at the bottom, or water leaks from the downspout joints during rain.

How do I unclog a downspout?

Clear the outlet, then run a hose down from the top. If it backs up, use a plumber's snake or take off the bottom elbow and flush upward.

How do I clear an underground downspout?

Flush it from the cleanout or catch basin with a hose, then use a drain snake or jetter if needed. A camera can find crushed sections.

Why does my downspout keep clogging?

It may be too small for the roof and trees, have too many elbows, or lack a guard or strainer at the outlet.

Guides

Clogged Downspout? How to Find and Clear the Blockage

When a gutter overflows right above a downspout, the pipe below is usually the problem. Most clogs sit in a few predictable places and can be cleared without taking anything apart.

Updated 2026-10-26 · Gutter Fixing Editorial Team

Downspouts are narrow compared with the gutter that feeds them. A handful of wet leaves, a tennis ball or a mat of seeds is enough to plug a 2x3 inch pipe. When it happens, the gutter fills and spills over, often right at the corner where the outlet is. Water that should go away from the house then lands right beside it.

Signs of a clogged gutter downspout

The gutter overflows near the outlet even after it has been cleaned.
Little or no water comes out of the bottom during rain.
Water leaks from the joints of the downspout partway down.
Standing water in the gutter after the rain stops.
Tapping the pipe gives a dull, solid sound at one point.
The pop-up emitter of a buried drain stays closed during heavy rain.

Where downspouts clog

Most clogs form at the outlet where the gutter drains into the pipe, in the elbows at the top where the pipe bends back to the wall, and in the elbow at the bottom. Straight sections rarely clog on their own. On buried systems, the connection at ground level and any low spot in the pipe are common trouble spots.

Clearing a downspout from the top

Clean the gutter around the outlet first and pull out any debris you can reach.
Run a garden hose down the outlet at full pressure to push the clog through.
If water backs up, feed a plumber's snake or a gutter cleaning wand down from the top to break up the clog.
Finish by flushing with the hose until water runs freely out of the bottom.

Work from a stable ladder with a standoff and never lean over the roof edge to reach. On high roofs, this is a job for a professional.

Clearing from the bottom

Sometimes it is easier to start at ground level. Remove the bottom extension and elbow, push the hose up the pipe, and let the water loosen the clog from below. Tap the pipe along its length to help debris break free. If the elbows at the top are packed, it may be quicker to unscrew them, clear them by hand and refit them with new screws.

Clearing a clogged underground downspout

A blocked buried downspout drain is harder because you cannot see inside it. Start at the cleanout or the catch basin, if there is one, and run a hose in at full flow. If water backs up, a drain snake or a pressure jetter pushed from the outlet end or the cleanout usually clears silt and roots. A plumber or drain contractor can run a camera to find a crushed or sagging section. Corrugated lines that keep filling with silt are often best replaced with smooth pipe.

Why downspouts keep clogging

Pipes too small for the roof area and debris, such as 2x3 under heavy trees.
Too many elbows close together at the top.
No guard or strainer on the outlet, so leaves go straight in.
Gutters cleaned too rarely, so debris washes into the pipe in storms.
Buried lines without a catch basin or with dips that collect silt.

Preventing clogs

Upsizing to 3x4 inch downspouts is one of the most effective changes on a house that keeps clogging, because the bigger pipe lets debris through. Fitting outlet strainers or gutter guards keeps most leaves out of the pipe. Fewer elbows, with a short straight section between the gutter and the wall, cut the number of tight bends. Flushing each downspout with a hose when you clean the gutters catches small clogs early.

Ice in downspouts

In cold weather, downspouts can freeze solid, especially where they run down shaded north walls or end in buried pipes. Do not hit a frozen downspout to clear it; that dents and splits the pipe. Let it thaw naturally, and if it happens every winter, consider heat cable in the downspout or rerouting it to a sunnier spot. The heated gutters page explains heat cable.

Contractors in our network can clear clogged downspouts and buried drains, replace damaged sections and upsize pipes. Gutter cleaning visits often include clearing downspouts from the top.

Tools that help

A garden hose with a strong jet nozzle.
A hand auger or plumber's snake long enough to reach the bottom elbow.
A gutter scoop and gloves to clear the outlet area.
A screwdriver or drill to remove and refit elbows.
A stable ladder with a standoff, and a helper to hold it.

Clogs in the gutter outlet

Sometimes the downspout itself is clear and the blockage is a ball of debris sitting over the outlet hole in the gutter. Leaves gather there because water flows toward the outlet and drops them as it slows. Pulling that ball out by hand often fixes an overflowing corner on the spot. A domed outlet strainer, sometimes called a leaf strainer, keeps it from forming again.

When to call for help

Call a professional when the clog is in a high second-story pipe, when a buried line will not clear with a hose and snake, when the downspout is crushed or split, or when clogs return every few weeks. Repeated clogs usually point to a design fix, such as a larger pipe or a guard, rather than more cleaning.

Noises that point to a clog

A gurgling or glugging sound during rain means air and water are fighting past a partial blockage. A steady drip with no flow means the pipe is nearly full. Rattling can mean a loose strap rather than a clog. Listening during the next storm is a quick way to find the problem pipe before climbing a ladder.