Direct answer: If a dog damaged your downspout extension, the right fix depends on what changed: a crushed or chewed end can sometimes be trimmed or reshaped, but a split, badly flattened, or repeatedly disconnected extension usually needs replacement.
Most likely: Most of the time, the damage is at the loose ground-level extension where chewing or tugging has crushed the outlet end, opened a seam, or pulled the extension off the downspout elbow.
Start with the visible damage and a simple water-flow check. You want to separate cosmetic chew marks from a real drainage problem before you buy anything. Reality check: even a small split or crushed end can dump a surprising amount of roof water right beside the foundation. Common wrong move: wrapping a mangled extension with tape and calling it fixed when the piece is still kinked and backing water up.
Don’t start with: Do not start by replacing the whole downspout run or burying the outlet to hide the problem. First confirm whether the extension still carries water away cleanly.
Tooth marks, scratches, or a rough outlet edge, but no obvious leaking along the extension during rain or hose testing.
Start here: Check for hidden flattening or a torn seam before deciding it is only cosmetic.
The outlet end is pinched down, folded, or partly closed off where the dog bit or stepped on it.
Start here: Start with shape and flow. A narrowed outlet can make the whole run spill early.
The extension is sitting off to the side, partly detached, or fully separated from the elbow or connector.
Start here: Look at the joint first. You need to know whether the extension slipped off or the connector itself cracked.
During rain, water dumps beside the house, sprays from a split, or runs out before it reaches the discharge point.
Start here: Treat this as a drainage failure, not just pet damage. Confirm the damaged piece is the leak point and not a clog upstream.
Dogs usually damage the loose, reachable section first. Once the wall opens up, water escapes before it gets away from the house.
Quick check: Run water from a hose into the downspout and watch for drips or spray along the damaged area.
A chewed or flattened end can act like a pinch point. Water may still move, just not fast enough in a heavy rain.
Quick check: Look straight through the extension. If the opening is badly narrowed or folded, that section is no longer doing its job.
Tugging and dragging often opens the joint where the extension meets the elbow or adapter.
Quick check: Wiggle the connection by hand. If it slides apart easily or will not stay aligned, the joint needs repair or replacement.
Pet damage gets blamed for everything, but a blocked extension can make a minor chew spot look worse than it is.
Quick check: After disconnecting the extension, run water down the downspout. If it still backs up or spills, the problem is not only the dog damage.
A lot of dog damage looks ugly but does not justify replacement. You only need to act if the shape, seam, or connection is compromised.
Next move: If the extension is only scuffed and still holds its shape, keep it in service and move on to a flow test. If you find an open seam, a torn connector area, or a badly pinched section, treat that piece as failed.
What to conclude: Visible wall damage or a narrowed outlet is enough to cause poor drainage even before a full blockage forms.
This separates a damaged extension from an upstream clog or a problem higher in the downspout run.
Next move: If water exits the elbow cleanly with the extension removed, the damaged extension or its connector is the main problem. If water backs up, trickles weakly, or spills from joints above, you likely have a clog or separate downspout issue too.
What to conclude: A clean elbow discharge points to a local extension failure. Poor flow with the extension removed means you should address blockage before buying extension parts.
Once flow is isolated, you can decide whether you need a new extension, a new connector, or just a better fit at the joint.
Next move: If the damage is limited to a small end section and the extension still fits tightly after cleanup or trimming, you may be able to reuse it. If the body is split, the inlet is stretched out, or the connector is cracked, replacement is the cleaner fix.
Most dog-damage repairs are local. Replacing only the bad extension or connector gets drainage working again without turning it into a bigger project.
Next move: If the new or reused piece fits snugly and holds shape, you are ready for a final water test. If the new extension still leaks or pops off, recheck alignment and make sure you are not dealing with a clog, buried outlet restriction, or a loose downspout above.
A repair is only done when water leaves the house cleanly and stays away from the foundation after the extension is back in place.
A good result: You have a finished repair when the extension stays connected, carries full flow, and leaves no pooling at the foundation.
If not: If water still cannot get away, the next problem is likely a clogged buried outlet, poor grading, or another drainage issue beyond the damaged extension.
What to conclude: Good flow with no early leaks confirms the dog-damaged piece was the real failure. Continued pooling means the extension repair was only part of the story.
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Yes, if the chew marks are only cosmetic and the extension still holds its shape, stays connected, and carries water without leaking. Once the wall is split or the outlet is pinched down, it is no longer just cosmetic.
Usually not for long. Tape may cover a small hole temporarily, but it does not restore shape to a crushed outlet or a stretched connection end. If the piece leaks or kinks, replacement is the better repair.
Remove the extension and run water through the downspout alone. If water exits the elbow strongly, the extension or connector is the issue. If flow is weak or backs up, you likely have a clog higher up or downstream.
Only if the elbow is bent, cracked, or no longer lines up with the extension. In many cases the elbow is fine and only the ground extension or connector needs attention.
Then the extension may be working, but the discharge area is not. Move the outlet farther away if possible, or troubleshoot the downstream drainage area, buried outlet, or grading problem next.
Either can work if it fits the layout and stays secure. The better choice is the one that holds its shape, matches the connection properly, and puts the outlet where water can leave the house cleanly.