How do I know if my downspout is clogged?

Signs of a clogged downspout: water overflows the gutter during rain even though the gutter itself is clean; water pours over the front edge of the gutter near the downspout; the downspout produces no water flow during rain or produces a trickle instead of a stream; or you can hear gurgling in the downspout. To confirm: run a garden hose into the top of the downspout from the roof. If water backs up instead of flowing through, it is clogged.

Can I clear a downspout from the ground?

Yes, for many clogs. Insert a garden hose into the bottom of the downspout and feed it upward as far as it will go, then turn on full pressure. The water pressure often dislodges compacted debris and pushes it out the bottom. If the clog is near the bottom elbow, this approach usually clears it without ladder work. For clogs higher in the downspout or at the top elbow near the gutter, you need to work from above with a hose or snake.

What is the best tool for snaking a downspout?

A 25-foot drain snake (plumber's snake) or a gutter cleaning attachment for a pressure washer works well. The gutter cleaning attachment has a curved nozzle that directs pressure into the downspout from the gutterline and is effective at dislodging packed leaves and debris. A pressure washer wand with a downspout attachment can clear most clogs in a single pass. For stubborn compacted debris, a hand-cranked drain snake fed from below is the most reliable option.

Why does my downspout keep clogging in the same place?

Repeat clogs in the same location point to a structural issue: a section of the downspout that has crimped inward, a joint that has separated and catches debris, an elbow angle that is too tight, or a section of underground drain pipe that is cracked and allows soil intrusion. Inspect the downspout sections around the clog location. Replace crimped or damaged sections. If the underground drain keeps clogging, run a camera scope through it to check for root intrusion or pipe failure.

How do I prevent downspout clogs from coming back?

Install a downspout strainer (a basket filter that fits into the top of the downspout at the gutterline) to catch leaves before they enter the downspout. Clean the strainer every fall and spring. Adding gutter guards over the gutter channels prevents most debris from entering the system at all. For areas with heavy tree coverage, plan on cleaning gutters and flushing downspouts twice a year — once in late fall after leaves drop, and once in early spring.

My downspout drains into an underground pipe and it is clogged. What do I do?

Disconnect the downspout from the underground drain at the boot or coupler at ground level. Flush the underground drain with a hose to test flow. If it is clogged, run a 50-foot drain snake into the underground pipe to break up the blockage. Flush again to confirm flow. If flow is still blocked after snaking: the underground pipe may have a root intrusion, a crushed section, or a separated joint. A plumber with a pipe camera can diagnose it. In the meantime, redirect the downspout above ground using a downspout extension that carries water 4–6 feet from the foundation.

How to Fix a Clogged Downspout: Flushing, Snaking, and Redirecting

A downspout that won’t drain turns the entire gutter into a holding tank.

A downspout that won’t drain turns the entire gutter into a holding tank. Flush it first — most clogs clear in under 30 minutes.

What you need

Diagnose where the clog is

Clogs most often form at one of three locations:

Top elbow (where the gutter outlet transitions to the vertical downspout run): leaves and shingle grit collect at this 90-degree bend
Mid-run in the vertical section: debris compacts between joints that have separated slightly
Bottom elbow (where the downspout turns from vertical to the discharge angle): mud and compacted leaf debris settles here

Start by removing the bottom elbow if accessible — just pop the crimped joint apart. Look for packed debris. Many clogs sit right at the bottom elbow and come out in one piece when the elbow is removed.

If the bottom elbow is clear, run a garden hose from the top of the downspout at the roofline with full pressure and observe where the water backs up.

Flush with a garden hose

From a ladder at the gutterline, feed a garden hose into the top of the downspout as far as it will reach and turn on full pressure. This forces water down through the clog and often pushes it out the bottom.

If the clog doesn’t clear: cap the bottom of the downspout temporarily with a rubber plug or have a helper hold a rag over the bottom, allow pressure to build for a few seconds, then release. The sudden pressure surge breaks apart compacted debris. Repeat two or three times.

Flush from below: insert the hose into the bottom and feed upward. Full pressure directed up into the clog can dislodge debris that top-flushing won’t reach.

Snake the downspout

If flushing doesn’t work, feed a 25-foot drain snake into the bottom of the downspout. Crank the snake clockwise as you push it in — the rotating tip breaks apart compacted leaf and debris packs. When you feel resistance, apply more rotational force before pushing farther.

Once the snake passes through the full length, pull it back slowly while continuing to crank. Debris will ride the snake out of the tube.

Flush with the garden hose again after snaking to confirm the downspout is clear and to wash out remaining debris.

A pressure washer with a downspout cleaning attachment is faster than a snake for most residential clogs — the rotating nozzle and high pressure clear debris in one pass without manual cranking.

Inspect and repair downspout sections

After clearing the clog, inspect the downspout for structural problems that will cause repeat blockages:

Separated joints: gaps between sections where one tube slides into the next. Debris catches on the edge. Reseat the joint and secure with a sheet metal screw. Apply gutter sealant on the interior of the joint seam.
Crimped or dented sections: aluminum downspouts dent from ladders and impacts. A section crimped more than 20 percent of its diameter will collect debris. Replace the damaged section — downspout sections are sold in 10-foot lengths and cut with tin snips.
Undersized elbows: original builder-grade elbows are sometimes 2-inch diameter. Upgrading to 3-inch or 4-inch reduces future clogging significantly.

Prevent future clogs

Install a downspout strainer basket at the gutterline — it sits inside the top of the downspout opening and catches leaves before they enter. Clean it twice a year.

If trees overhang the roofline and the gutters fill with debris every season, gutter guards over the gutter channel keep the downspout inlet clear by keeping large debris out of the gutter entirely.

For downspouts draining into underground pipes: disconnect and redirect above ground if the underground system clogs repeatedly. A 6-foot flexible downspout extension carrying water away from the foundation costs $15 and eliminates the underground maintenance problem.

How to Clean Gutters
How to Fix a Sagging Gutter
How to Fix Leaking Gutters
How to Install a Downspout
How to Fix a Broken Gutter Downspout — repair a cracked or disconnected downspout section

⏰ PT1H 💰 $10–$60

Diagnose where the clog is
Remove the bottom elbow (pop the crimped joint apart) and look for packed debris — many clogs sit right here. If the bottom elbow is clear, run a garden hose from the top of the downspout at full pressure and watch where water backs up. Clogs most often form at the top elbow, mid-run joints, or bottom elbow.
Flush with a garden hose
Feed a garden hose into the top of the downspout and turn on full pressure. If the clog doesn't clear, plug the bottom temporarily with a rubber plug or rag, let pressure build for a few seconds, then release — the pressure surge breaks compacted debris. Also try flushing from below: insert the hose into the bottom and feed upward.
Snake the downspout
Feed a 25-foot drain snake into the bottom of the downspout. Crank clockwise while pushing in to break apart compacted leaf and debris packs. When resistance decreases, pull the snake back slowly while continuing to crank — debris will ride the snake out. Flush with the garden hose again to confirm the downspout is clear.
Inspect and repair sections
After clearing, inspect for structural problems that will cause repeat clogs: separated joints (reseat and seal with a sheet metal screw and gutter sealant), crimped or dented sections (replace the damaged 10-foot section), and undersized elbows (upgrade to 3-inch or 4-inch to reduce future clogging).
Install a strainer to prevent future clogs
Install a downspout strainer basket at the gutterline — it fits inside the top of the downspout opening and catches leaves before they enter. Clean it twice a year. For chronic clogging from heavy tree coverage, install gutter guards over the gutter channel to keep large debris out of the system entirely.

How to Fix a Clogged Downspout: Flushing, Snaking, and Redirecting

What you need

Diagnose where the clog is

Flush with a garden hose

Snake the downspout

Inspect and repair downspout sections

Prevent future clogs

Free: 10-Point Home Maintenance Checklist

Save this for next time.

How to Fix a Clogged Downspout: Flushing, Snaking, and Redirecting

What you need

Diagnose where the clog is

Flush with a garden hose

Snake the downspout

Inspect and repair downspout sections

Prevent future clogs

Related guides

Free: 10-Point Home Maintenance Checklist

Save this for next time.