Direct answer: If a squirrel damaged your downspout extension, the usual fix is replacing the chewed or crushed extension section, not the whole downspout. Start by checking whether the damage is only at the end, at a joint, or close enough to the wall that water is now spilling at the foundation.
Most likely: Most often, squirrels chew or tear a plastic downspout extension near the outlet end or at a loose connection, leaving a split that leaks or catches debris.
Animal damage on a downspout extension is usually pretty visible: tooth marks, a ripped flap, a crushed corner, or a section pulled partly apart. The important part is separating simple extension damage from a clog or a loose upper downspout. Reality check: if the extension is thin plastic and badly chewed, replacement is usually faster and cleaner than trying to patch it. Common wrong move: forcing a new piece onto a clogged or misaligned outlet and wondering why it still overflows.
Don’t start with: Do not start by sealing everything with tape or caulk. That hides the real shape of the damage and usually fails after the next hard rain.
The extension has tooth marks, a flap torn open, or a small hole near the discharge end, but the rest of the run still lines up.
Start here: Start with a close visual check and a hose test to see whether water escapes only from that damaged spot.
The extension is loose, partly detached, or leaking where it slips onto the downspout elbow or outlet.
Start here: Check fit, alignment, and whether the connector area is cracked before replacing the whole extension.
The extension looks stepped on, collapsed, or pinched after animal activity, and water backs up or spills out upstream.
Start here: Treat this like a flow problem first and check whether the crushed section is restricting water.
Leaves and shingle grit keep catching at the damaged area, and overflow shows up during heavier rain.
Start here: Inspect for a torn edge or narrowed opening that is acting like a snag point, then confirm the rest of the run is clear.
This is the most common squirrel damage. You will usually see tooth marks, ragged edges, or a puncture in a flexible plastic extension.
Quick check: Run water from a hose into the downspout and watch for a clean leak at the damaged spot.
Squirrels often worry a loose end or already-wobbly joint. The damage shows up where the extension meets the outlet or elbow.
Quick check: Wiggle the connection by hand. If it shifts easily or opens up, the joint or connector is the real failure point.
A chewed section can fold inward or collapse enough to slow flow, especially on thin corrugated plastic.
Quick check: Look down the extension opening. If the passage is pinched smaller than the rest of the run, expect backup and spillover upstream.
Sometimes the squirrel damage is real, but the overflow only became obvious because leaves and grit started catching on the torn edge.
Quick check: Clear visible debris and test flow. If water still backs up well before the damaged spot, there is likely a blockage farther in the extension or outlet.
You want to know whether you are dealing with a simple chewed section, a failed joint, or a bigger drainage problem. That keeps you from replacing the wrong piece.
Next move: You can point to one clear damaged spot or one loose connection that explains the leak or poor drainage. If you cannot find visible damage but water still spills out during rain, treat it as a clog or disconnected run instead of animal damage alone.
What to conclude: Visible chewing with no distortion usually means a local repair or section replacement. Damage plus sagging, separation, or standing water points to a connection or blockage problem too.
A torn extension can leak without being clogged, and a crushed section can act like a clog. Those are different fixes.
Next move: You now know whether the main issue is a local leak, a bad connection, or restricted flow. If water will not move through the run at all, stop chasing the chew marks and inspect for a clog in the extension or buried outlet.
What to conclude: A clean leak from one spot supports replacing that damaged extension section. Weak discharge or backup means the damaged area may be catching debris or the line beyond it is blocked.
A lot of squirrel-damaged extensions are actually failing at a loose joint. If the connection is cracked or undersized, a new extension alone will not stay put.
Next move: You can tell whether the extension itself is the problem or whether the joint hardware is worn out or cracked. If the connection looks fine but water still backs up, move on to checking for a crushed section or hidden blockage.
Once you know where the failure is, the clean repair is usually straightforward and lasts longer than patching chewed plastic.
Next move: Water stays inside the run and exits at the far end without leaking near the house. If the new section still backs up or blows apart, the real problem is usually a clog, poor alignment, or a buried outlet issue farther downstream.
A repair is not done until you know water leaves the house cleanly and does not dump at the foundation.
A good result: The extension carries water away from the house without leaking, backing up, or separating.
If not: If the repaired section is dry but the system still overflows, the next job is clearing the downstream blockage or correcting the layout.
What to conclude: You have either finished the repair or narrowed it to a drainage problem beyond the damaged extension.
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Only as a very short temporary measure, and only if the extension is otherwise solid. On chewed or weathered plastic, tape usually lets go quickly once the piece flexes, gets wet, or heats up in the sun.
If you only see light tooth marks and the extension still holds water flow without leaking, catching debris, or collapsing, it is mostly cosmetic. If there is a hole, torn flap, crushed section, or repeated clogging at that spot, repair or replacement is the better move.
Usually just the extension or the failed connection piece. Replace the upper downspout only if it is also bent, loose, cracked, or pulling away from the wall.
That usually means the damage was not the only problem. Look for a crushed section, a poor connection, or a clog in the buried outlet or downstream drainage path.
Yes. If the damage lets water dump right beside the house, repeated rain can soak the soil at the foundation, wash mulch and soil away, and send water toward the basement or crawlspace.
Most often it is the downspout extension itself. The next most common is a connector or elbow at the joint if the animal worked on a loose connection.