Water comes in only during wind-driven rain
The floor gets wet after storms, especially when rain hits that side of the house hard.
Start here: Focus on the door sweep, threshold seal, and whether the door is pulled tight and even when latched.
Water getting in under a door
Door Leaking at Bottom
Direct answer: If a door is leaking at the bottom, the usual cause is not the slab itself. Most of the time the bottom seal is worn, the threshold is not sealing, or the door is sitting out of alignment so wind-driven rain can get past the bottom edge.
Most likely: Start with the leak pattern. Water only during rain points to the door sweep, threshold, weatherstripping, or door alignment. Water without rain often turns out to be condensation, wet flooring, or water tracking from nearby trim or siding.
Look at where the water first appears, not where the puddle ends up. A few paper towels and a close look during or right after rain will usually tell you whether water is coming under the door, around the jamb, or from somewhere nearby and just collecting at the bottom. Reality check: a surprising number of 'door leaks' are really water being blown or drained toward the opening from outside. Common wrong move: replacing the door sweep before checking whether the door is sagging and barely touching the threshold on one side.
Don’t start with: Do not start by smearing caulk across the threshold or buying a whole new door. Blind caulking often traps water and hides the real path.
Leaks only during rainCheck the bottom sweep, threshold contact, and whether one corner of the door has a wider gap.
Moisture shows up without rainRule out condensation, wet floor migration, or water tracking from nearby wall or trim before replacing door parts.
Last reviewed: 2026-04-05
What this usually looks like
Water shows up at one bottom corner
One side of the threshold stays dry while the latch side or hinge side gets wet first.
Start here: Look for a sagging door, loose hinges, or a threshold that is lower on one side.
The inside face of the door is damp but there was no rain
You see beads of moisture or a damp strip near the bottom edge during humid or cold weather.
Start here: Treat this as a condensation check first, not a leak repair.
The threshold area stays wet even after the door parts look decent
The sweep looks intact, but water still appears near the sill or trim.
Start here: Check whether water is being directed toward the opening from outside surfaces, clogged weep paths, or failed sealant around the frame exterior.
Most likely causes
1. Worn or compressed door sweep
This is the most common true under-door leak. The rubber or vinyl edge hardens, tears, or stops touching the threshold evenly.
Quick check: Close the door on a dry day and look for daylight or an uneven gap under the bottom edge. A dollar bill should drag with some resistance across the full width.
2. Door threshold not sealing or sitting out of level
If the threshold is low, loose, or worn, water can pass under the sweep even when the door itself is fine.
Quick check: Look for a polished wear path, loose fasteners, cracked seal areas, or a spot where the sweep barely touches one side.
3. Door slab out of alignment from loose hinges or frame movement
A slightly sagging door often leaks at one bottom corner first because the sweep contact is uneven.
Quick check: Stand back and compare the reveal around the door. A tight top corner and wide opposite bottom gap usually means alignment is off.
4. Water is reaching the opening from outside, not just slipping past the bottom seal
Splashback, poor drainage, missing exterior sealant, or water running down the jamb can make the threshold area look like the source.
Quick check: During rain, watch the outside edge of the frame and threshold. If water is pooling, running down the jamb, or blowing sideways into the opening, the source is upstream.
Step-by-step fix
Step 1: Separate a real rain leak from condensation or tracked water
You do not want to replace door parts for moisture that is forming on the door or being carried in from somewhere else.
- Wipe the door, threshold, and floor dry.
- Lay a strip of paper towel along the inside bottom edge and another along each lower jamb leg.
- Note whether the moisture appears after rain, after mopping, after snow on shoes, or during humid weather with no rain.
- If the inside face of the door is sweating evenly or feels cool and damp without rain, suspect condensation first.
Next move: If you confirm the moisture is not tied to rain and is forming on the surface, treat it as a condensation or indoor moisture issue instead of a bottom-seal failure. If the paper towel at the bottom edge gets wet during rain, keep going. You are dealing with actual water intrusion at or near the opening.
What to conclude: This tells you whether to chase a seal problem or a moisture problem.
Stop if:
- Water is coming from inside the wall, not the door opening.
- The floor or subfloor feels soft, swollen, or rotten.
- You see moldy trim, crumbling drywall, or long-term staining around the frame.
Step 2: Check where the leak starts during or right after rain
The first wet spot usually tells the truth. The puddle on the floor often does not.
- Inspect the threshold, both bottom corners, and the lower 12 inches of each jamb right after rain.
- Look outside for pooling water, splashback, clogged sill channels, or a patio or stoop that pitches toward the door.
- Watch whether water is running down the face of the door, down the jamb, or appearing directly under the slab.
- If only one corner leaks, compare the gap under the door from side to side.
Next move: If you find water arriving from the jamb or exterior edge first, the bottom seal may be innocent and the outside water path needs attention. If water appears directly under the center or along the full bottom edge, the sweep or threshold seal is the stronger suspect.
What to conclude: This separates an under-door seal failure from water being driven or drained into the opening from outside.
Step 3: Test the bottom seal and threshold contact
A door can look fine and still miss the threshold by just enough to leak in a storm.
- Close and latch the door fully.
- Slide a dollar bill or thin strip of paper under the closed door from the inside at several points across the width.
- Feel for even resistance. Little or no drag at one spot means poor contact there.
- Inspect the door sweep for tears, flattened sections, hardened rubber, or a gap at the corners.
- Check whether the threshold is loose, worn, or visibly lower on one side.
Next move: If the sweep is damaged or the contact is weak in the same area that leaks, you have a solid repair direction. If contact looks even and the sweep is healthy, move on to alignment and exterior water path checks.
Step 4: Check door alignment before replacing seals
A new sweep will not fix a door that is hanging low or twisting away from the threshold at one corner.
- Open the door and tighten any loose hinge screws on the door and frame side.
- Look for rubbed paint, shiny wear marks, or a top corner that is tighter than the rest of the reveal.
- Close the door and confirm the latch pulls the slab snug against the weatherstripping.
- If the leak is at one bottom corner, compare the bottom gap there to the opposite side.
Next move: If tightening hinges improves the reveal and the bottom contact, test the door in the next rain before buying parts. If the door still sits unevenly or the latch does not pull it tight, the frame may be out of square or the door may need adjustment beyond a simple seal replacement.
Step 5: Replace the failed seal part, then retest the next rain
Once you know whether the problem is the sweep, threshold contact, or alignment, you can fix the right thing instead of layering on caulk.
- Replace the door sweep if it is torn, hardened, shrunken, or not contacting the threshold evenly.
- Replace the door weatherstripping if the latch side or bottom corners are not being pulled tight and the seal is flattened or missing.
- Replace the door threshold if it is worn, loose, or no longer gives the sweep a consistent sealing surface.
- After the repair, close and latch the door and repeat the paper or dollar-bill contact test across the bottom.
- Retest during the next rain and watch the first place moisture appears, if any.
A good result: If the threshold area stays dry through a normal rain, the repair is holding.
If not: If water still shows up after the seal parts and alignment check out, the problem is likely outside the door assembly and needs exterior water-path repair or a pro inspection for hidden damage.
What to conclude: A dry retest confirms the source. A repeat leak after good seal contact points to drainage, frame sealing, or surrounding construction.
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FAQ
Why is water coming in under my front door only when it rains hard?
That usually points to a sealing or water-direction problem, not the door slab itself. Wind-driven rain can get past a worn door sweep, a low spot in the threshold, or a door that is slightly out of alignment at one corner.
Can I just caulk the inside edge of the threshold?
Usually no. Interior caulk may hide the symptom for a while, but it does not stop water from reaching the opening. In some cases it traps water where you do not want it. Find the entry path first, then fix the sweep, threshold, alignment, or exterior water path.
How do I know if it is the door sweep or the threshold?
If the sweep is torn, hard, or not touching evenly, start there. If the sweep looks decent but the threshold is worn, loose, or lower where the leak happens, the threshold is the better suspect. The dollar-bill test across the bottom helps separate the two.
Why does the leak happen at just one bottom corner?
One-corner leaks usually mean the door is hanging slightly out of square, the threshold is uneven, or the sweep is damaged at that corner. Loose hinges are a common reason the latch side bottom corner starts leaking first.
When is this more than a simple seal repair?
If the jamb bottoms are soft, the threshold is rotted, the floor is swelling, or water is showing up from inside the wall, you are past a simple seal issue. At that point you may be dealing with hidden damage or an exterior water-management problem that needs a deeper repair.