Last updated: 15 September 2026
When a frameless shower door starts leaking, the first thought is often that the seal needs replacing.
Sometimes it does. But the harder part is usually working out where the water is actually getting out.
A puddle on the floor does not always sit directly below the leak. Water can run down the glass, travel along a seal or follow the edge of the shower tray before it finally drops outside.
So before changing anything, dry the glass and the floor, then run the shower again.
Where does the first bit of water appear?
Once you know that, it is much easier to tell whether the problem is the seal, the gap or the door itself.
If you are still not sure where to start, our shower leak guide breaks the problem down by leak location.
Is the Whole Bottom Edge Leaking, or Just One Corner?
If water is escaping along most of the bottom edge, start with the bottom seal and the gap underneath it.
The seal may have distorted, the fin may no longer reach the shower tray, or the profile may simply not suit the actual gap.
If most of the bottom edge is wet, this is closer to a typical shower door leaking at the bottom problem.
One wet corner is different.
The lower corner of a frameless door is often where several parts meet. A bottom seal may finish near a vertical seal, hinge area or threshold, and even a small break between them can give water a way out.
A few millimetres can be enough.
If the leak is confined to one lower corner, it is usually better treated as a shower corner leak rather than a problem with the whole bottom seal.
When we look at fitting photos from customers, this is one of the more common mistakes we see. Water is found on the floor, so the bottom seal gets blamed first, even though the leak actually starts at the corner or higher up.
What If the Water Is Coming From the Hinge Side?
The hinge area is a little different from a straight glass edge.
The door needs room to move, so the seal around the hinge is not always completely continuous.
If most of the hinge side is wet, look at the hinge-side gap and the seal around it.
If it is only the very bottom corner, that points more towards a corner leak.
Water can also hit the glass higher up and run down beside the hinge, which makes the leak look lower than it really is.
If the water is clearly escaping around this side of the door, our guide to a shower screen leaking at the hinge goes into that area in more detail.
Is It Leaking Between Two Glass Panels?
If water is getting out between a fixed panel and a moving door, look at the closing gap between the two pieces of glass.
Check it from top to bottom.
If the gap is narrow at the top but clearly wider lower down, or one section no longer meets properly, the seal may not be the whole problem. The door may have dropped slightly or moved out of alignment.
If the gap looks fairly even, then look at whether the vertical seal, H-shaped seal or magnetic seal is actually covering it properly.
A bottom seal will not usually solve this kind of leak.
Is the Water Coming From the Wall Side?
If water appears between a fixed glass panel and the wall, start with the wall-side connection.
That could mean the wall-side gap, the vertical seal, the fixing profile or the sealed joint between the glass and the wall.
It is not usually a bottom-seal problem.
This is especially worth checking if a new bottom seal has already been fitted and nothing has changed.
The gap at the wall can be tiny, yet the water may still run down and only become obvious once it reaches the tray.
Still Not Sure? Test One Area at a Time
Water does not always fall straight down from the point where it escapes.
If the source is difficult to spot, dry everything again and test one area at a time.
Start with the bottom of the door. Then try the hinge side. Then the gap between the glass panels.
That is usually much easier than spraying the whole enclosure at once and trying to work backwards from the puddle.
Sometimes a New Seal Will Not Fix It
Not every frameless shower leak is caused by the seal.
If the door has dropped and the gap changes noticeably from top to bottom, the alignment needs checking.
If the shower tray is sending water towards the outside edge, a longer fin may not solve the underlying problem.
Loose fittings, a leaking wall joint or failed silicone will not be fixed by replacing the bottom seal either.
A newly installed shower enclosure that has leaked heavily from day one is also worth checking before trying different seals. The glass position, door alignment, gap or tray installation may be the real issue.
If you still cannot work out where the water is getting out, you do not have to keep guessing. Send SIMBA Seals UK a photo of the whole door, the leaking area and the seal already fitted.
We can help narrow down whether the problem is the seal, the gap or the door position before you start replacing parts.
Laura has worked with SIMBA since 2017, helping customers identify replacement shower door seals from old profiles, glass measurements and fitting photos. She also deals with everyday fitting problems including bottom leaks, corner leaks, hinge-side leaks and door misalignment.