Last updated: 21 October 2026
When a shower door leaks at the bottom, replacing the seal often seems like the obvious fix. But a new seal doesn't always stop water reaching the bathroom floor.
We've helped customers whose bottom seals grip the glass securely and whose doors close normally, yet water still escapes underneath. The fin might not cover the gap properly, or the seal may be the wrong shape for the door. We've also seen water running down from the frame rather than escaping beneath the glass.
Before buying a replacement, it's worth finding out where the leak actually starts.
Where Is the Water Coming From?
Water on the bathroom floor doesn't always mean the bottom seal is leaking. It could have run down the glass or frame first.
Start by drying the bottom of the door, the edge of the shower tray and the surrounding floor. Then use a little water to check one area at a time. Watching where the water first appears is usually more useful than looking at the puddle after a shower.
| What you notice | What to check first |
|---|---|
| Water escapes directly beneath the glass | A missing bottom seal or a fin that doesn't cover the gap |
| Only one end of the door leaks | An uneven bottom gap or a fin lifting at one end |
| A new bottom seal still leaks | The seal's shape, fin length and fitting direction |
| Water seeps from the bottom rail or frame | Trapped water, drainage openings and frame joints |
| Water runs over the shower tray entrance | The water barrier and the direction of water flow |
| Water appears at a bottom corner | Where the vertical and bottom seals meet |
When the leak is confined to one corner, look upwards along that side of the glass and frame. The water may be running down from elsewhere rather than escaping along the whole bottom edge.
Common Causes of a Shower Door Leaking at the Bottom
1. There's No Bottom Seal Fitted
Some shower doors are installed without a bottom seal. Others have had an old seal removed or damaged, and a suitable replacement has never been found.
With the door closed, look for an open gap between the bottom edge of the glass and the shower tray. When water escapes directly through that space, a missing seal is one of the first things to investigate.
Even a small gap can allow water running down the glass to pass underneath.
Not every shower door needs an additional bottom seal, though. Some designs rely on their existing water barriers, so the original door arrangement matters too.
2. The Bottom Seal Is Worn or the Wrong Shape
A shower door seal doesn't have to split or fall off before it starts leaking.
The seal may still grip the glass firmly, even when the flexible fin underneath has gone stiff, curled up or lost its shape. Once it stops covering the gap properly, water can pass beneath it.
A brand-new seal can cause a similar problem when it's the wrong type.
We've seen customers fit an F-shaped seal with a sideways-projecting fin along the bottom of a shower door. The seal grips the glass, but its fin points out to the side rather than covering the gap between the glass and the tray.
Replacing it with another seal of the same design is unlikely to stop the leak.
This type of F-shaped seal is generally better suited to a vertical glass edge, where its side fin can help keep water from passing through a joint. Along the bottom of a door, a suitable seal needs to cover the gap beneath the glass.
A seal can fit the glass perfectly and still be wrong for the bottom of the door.
Some bottom seals also have fins designed to direct water back into the shower. Fitting one the wrong way round can prevent it from doing its job.
3. The Gap Beneath the Door Is Too Large or Uneven
Sometimes the fin covers the gap at one end of the door but leaves a small opening at the other.
Measuring only the middle of the glass can miss this.
With the door fully closed, check the gap near the hinge, in the middle and at the opposite end. A noticeable difference could mean the door has shifted out of position.
A fin that's too short may not reach the tray. But a longer fin isn't always better.
We've also seen customers choose a fin that's much longer than the gap, with material that's relatively stiff. As the door closes, the fin gets pushed against the tray and bends awkwardly. Near the hinge, it can lift away and leave a small opening for water to escape.
With this type of bottom seal, the fin should cover the gap without being crushed or bent awkwardly when the door closes.
Choosing a replacement also means checking the glass thickness and the size of the bottom gap. Our shower door bottom seal guide explains the measurements to take and the different seal designs available.
4. Water Is Escaping from a Bottom Corner
Hinged shower doors sometimes leak at one or both bottom corners, even when the bottom seal looks undamaged.
The problem may be where the vertical side seal meets the bottom seal. A small opening between the two can let water run down the edge of the glass and escape at the corner.
Without a suitable water barrier at the entrance, water escaping at this point may find its way over the edge of the tray more easily.
Even with a threshold strip fitted, it's worth checking where the bottom fin sits when the door is closed. On designs that rely on the fin and threshold overlapping, the fin should sit on the shower side of the strip. If it falls on the bathroom side instead, water may still escape.
We've covered the joint between the seals and the position of the threshold strip in more detail in our guide to shower door leaks at the bottom corners.
5. The Water Is Coming from the Side or Bottom Frame
Water may collect at the bottom of a shower door even though the leak starts somewhere else.
It can get through a joint along the side of the glass or frame, run downwards and eventually reach the bathroom floor.
Framed shower doors have another area worth checking: the bottom metal track.
Some framed doors have drainage holes or channels that allow water collected in the track to flow back into the shower. Dirt or soap residue can block these openings, leaving water to build up and escape through another joint.
Water seeping from beneath the bottom rail may also point to a problem with the sealant around the fixed frame where it meets the shower tray.
When water runs across the shower tray entrance rather than directly beneath the moving glass, look at the direction of the water flow and the existing barrier.
A new bottom seal won't necessarily help with leaks coming from the frame or tray edge.
Before Replacing the Bottom Seal
Once you've confirmed that water is escaping directly beneath the moving glass, measure the glass thickness and the gap below the door. A photo of the end of the existing seal will also help identify its shape.
Our guide to sealing the bottom of a shower door covers the checks and fitting steps for a bottom seal that needs installing, replacing or adjusting.
For a worn or unsuitable seal, you can use those measurements to compare replacement options in our shower door bottom seals collection.
Water coming from a frame joint, bottom corner or shower tray edge may need a different solution.
Not sure where the water is getting through? Send us a photo of your shower door and a close-up of the leaking area. We'll help you check what might be causing it before you order a replacement.
