Crushed in one obvious spot
One section is flattened or sharply folded, and water slows down or spills before that point.
Start here: Check whether that spot was stepped on, run over, or bent too tightly around a corner.
Downspouts / Extensions
Downspout Extension Kinked
Direct answer: A kinked downspout extension usually means water is being pinched off at one crushed bend or sagging section. Start by finding the exact pinch point, then check whether the extension is just bent out of shape, being stepped on, or backing up because the outlet end is blocked.
Most likely: Most of the time, the extension is flexible plastic that got flattened by foot traffic, mower wheels, or a bad turn right at the elbow. If the kink keeps coming back, the run is too long, unsupported, or draining into a clogged buried line.
Treat this like a drainage path problem, not just a cosmetic dent. A small pinch can make the extension hold water, spill at the foundation, or back water up into the downspout during a hard rain. Reality check: if the extension is thin corrugated plastic and badly crushed, replacement is often faster than fighting it. Common wrong move: forcing a tighter bend to make it fit around landscaping, which usually creates the next kink.
Don’t start with: Do not start by replacing the whole downspout or stuffing the line with sealant. A lot of these are simple shape and routing problems.
If the crushed spot is near the end and the rest is sound,shorten or replace that section instead of rebuilding the whole run.
If straightening the kink does not restore flow,look for a clogged buried outlet or a low spot holding water farther downstream.
Last reviewed: 2026-04-05
What a kinked extension usually looks like
Keeps kinking in the same place
You straighten it, but it folds again after the next rain or after yard work.
Start here: Look for poor support, too much length, or a turn that is tighter than the extension can hold.
Looks kinked but also holds water
The extension sags, feels heavy, or dribbles long after the rain stops.
Start here: Check for a low spot or a blocked outlet end before assuming the kink is the only problem.
Backs up at the downspout elbow
Water spills at the top connection or shoots out at the elbow during rain.
Start here: Make sure the extension itself is not pinched right at the elbow and that the outlet end is not blocked or buried.
Most likely causes
1. Flexible downspout extension crushed by traffic or yard equipment
This is the most common cause when the kink is low to the ground and sharply flattened.
Quick check: Follow the run and look for tire marks, footpath wear, or a flattened rib pattern in one section.
2. Extension routed with too tight a turn
Corrugated extensions fold over when they are forced around a bed edge, walkway, or corner without enough radius.
Quick check: Look where the extension changes direction. If the bend is abrupt instead of sweeping, that is your trouble spot.
3. Sagging run creating a low spot
A low section fills with water, gets heavy, and then collapses into a kink even if the plastic was fine at first.
Quick check: Lift the extension by hand. If water shifts inside or one section stays full, the slope is wrong.
4. Blocked outlet or buried drain downstream
When water cannot exit, pressure and standing water make the extension buckle, especially near the connection.
Quick check: Disconnect the extension at the downspout and run a hose through it. If flow is weak at the far end, the blockage is farther down.
Step-by-step fix
Step 1: Find the exact pinch point before moving anything
You want to separate a simple crushed section from a bigger drainage problem. The visible kink is not always the only restriction.
- Wait until the extension is not carrying roof runoff, or test with a garden hose instead of during a storm.
- Walk the full length from the downspout elbow to the outlet end.
- Mark every tight bend, flattened section, sagging low spot, and loose connection.
- Check whether the outlet end is buried in mulch, dirt, leaves, or grass clippings.
Next move: If you find one obvious crushed spot and the rest of the run is open and sloped, you can usually correct that section without chasing other causes. If the whole run is wavy, full of water, or badly misshapen in several places, plan on rerouting or replacing the extension.
What to conclude: A single damage point usually means traffic or a bad bend. Multiple weak spots usually mean the extension layout is the real problem.
Stop if:
- The ground near the foundation is already washing out or settling.
- The extension is attached to a buried line you cannot identify clearly.
- You need to work from a ladder to reach a loose upper downspout connection.
Step 2: Open the easy blockage at the outlet end
A blocked outlet can make a good extension act kinked because water has nowhere to go.
- Pull the outlet end into the open so you can see it clearly.
- Remove leaves, mulch, mud, and packed grass by hand.
- If the end is slit-style or hinged, make sure it can open freely and is not glued shut by dirt.
- Rinse the extension with a hose from the downspout side and watch how fast water exits.
Next move: If water now runs freely and the extension keeps its shape, the kink was being made worse by a blocked outlet. If flow is still weak or the extension swells and sags, keep going and check the shape and slope of the run.
What to conclude: A simple outlet blockage is common after mowing, leaf drop, and mulch refreshes. Weak flow after cleaning points to a pinch, low spot, or downstream clog.
Step 3: Straighten the run and test whether the kink is only a shape problem
Many extensions are still usable if the bend is mild and the run can be laid out with a smoother path.
- Disconnect the extension from the downspout elbow if that can be done at ground level.
- Lay the extension out as straight as the yard allows, with a gentle continuous fall away from the house.
- Massage minor flattened corrugations back into shape by hand. Do not crease them harder.
- Trim back landscaping pressure points or move the run so it does not have to make a sharp turn.
- Reconnect and run water through it again.
Next move: If water moves cleanly and the extension no longer folds, keep the gentler route and secure it so it stays there. If the same section collapses again or stays pinched, that piece is too damaged or too weak to trust.
Step 4: Check for a hidden low spot or downstream clog if the extension still acts full
If the extension feels heavy or keeps sagging, standing water is usually the reason. Straightening alone will not fix that.
- Lift the extension in sections and feel for trapped water.
- Look for a dip where the extension crosses a rut, edging, or settled soil.
- If the extension feeds a buried line, disconnect it and test the extension by itself first.
- If the extension drains fine when disconnected but not when attached to the buried line, the buried line or outlet is the problem.
Next move: If the extension drains normally once the low spot is removed or the buried line is bypassed, you have the right target. If the extension still collapses even with open discharge and proper slope, replace the damaged extension and any crushed elbow or connector at the same time.
Step 5: Replace the damaged section or reroute the extension so it cannot kink again
Once the plastic has a hard crease or keeps collapsing, repair time is over. A fresh piece with a better path is the durable fix.
- Replace a badly crushed flexible downspout extension with a new extension of similar size and outlet style.
- Replace a deformed downspout elbow or downspout connector if the pinch is right at the connection and the new extension still will not sit correctly.
- Shorten an overlong run or change the route so the extension makes broad turns instead of sharp ones.
- Add a downspout strap or support only if the extension or lower downspout section is shifting enough to create the kink.
- Run a final hose test and watch the full path from elbow to outlet.
A good result: If water exits freely, the extension stays open, and nothing backs up at the elbow, the repair is done.
If not: If a new extension still backs up, stop chasing the extension and move to the buried outlet or downstream drainage problem.
What to conclude: A replacement extension fixes crushed plastic. A repeat backup after replacement points to a clogged buried outlet, not bad luck with the new part.
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FAQ
Can I just straighten a kinked downspout extension?
If the bend is mild and the plastic is not split, sometimes yes. If it has a hard crease or keeps folding in the same place, replacement is usually the better fix.
Why does my downspout extension keep kinking after I fix it?
Usually because the route is too tight, the run has a low spot that holds water, or the extension keeps getting stepped on or run over. A blocked buried outlet can also make the problem come back.
Will a kinked extension cause gutter overflow?
Yes. If the extension pinches flow enough, water can back up at the elbow and contribute to overflow higher up during a hard rain.
Should I replace the elbow too?
Only if the elbow itself is bent, crushed, or misaligned. If the elbow is sound and the extension is the only damaged piece, replace the extension first.
What if the extension drains fine when disconnected from the buried line?
That points to a clogged buried downspout line or blocked outlet downstream. In that case, the extension is not the main problem anymore.