Water in boot HONDA CIVIC VIII Hatchback (FN, FK)

Ah, the classic Honda Civic VIII “rainy boot” saga! If I had a quid for every Civic owner who discovered a secret indoor swimming pool after a storm, I’d be writing this from somewhere sunny. At least you don’t need snorkelling gear… yet.

So, you’ve poked and prodded and found that water’s coming in from the back of the roof gutter rail. That’s a very Honda place for a leak—almost as if they wanted us to practice our detective skills. The Mk8 Civics (FN, FK) are notorious for water sneaking in via that gutter rail—usually at the ends, where the trim meets the back of the roof and over the boot.

Here’s what’s actually happening:
The sealant or the join in the gutter rail (sometimes the seam behind the trim itself) dries out, cracks, or gaps open a bit over time, letting water wick or drain under the trim. It then tracks sneakily down inside the C-pillar (the rear corner of the roof), finally dripping into your boot. You might see it running down behind the interior panels, often near the rubber loom/grommet or where the wiring goes to the tailgate. Sometimes, the end of the gutter trim is loose, or water tracks over the edge and straight into an unsealed gap—spot the drips behind the carpet or in the spare wheel well? Honda magic at work.

What do clever (read: frustrated but determined) Civic owners do?

- Carefully pop off the rear end of the roof gutter trim (that long, thin plastic/rubber piece that runs along the roof) where it meets the rear of the car. Don’t go all Hulk on it or you’ll snap the clips—gentle lever with a plastic trim tool works best.
- Look for cracks, gaps, or missing sealant in the metal seam or under the trim itself—sometimes you’ll find peeling or missing old seam sealer, or a gap around where the trim ends and the C-pillar meets the roof.
- Clean the area thoroughly and dry it (hairdryer on a dry day, or toss a dehumidifier in the boot for bonus points).

- Use automotive seam sealer or non-acidic silicone to re-seal the joint or gap at the trim end, and pay special attention to any cracks or splits in old sealant under the gutter. Some brave souls use lacquer as a waterproofing too, but silicone is easier to re-do in the future.
- Let it cure, then refit the trim and test with a watering can or hose—aim along the gutter for best “Honda simulation.”

Bonus tip: Some people also seal the holes for the boot hinges or the loom grommet, as water loves finding any tiny route to ruin your day. Be sure not to block any factory drain holes; you want to guide water out, not trap it even more.

Small job, but tricky to spot first time—so if it’s dry after DIY detective work, bask in the glory. And tell your Civic: no more mischief, or you’ll start charging for indoor pool use.

If this doesn’t cure it, check nearby: taillight seals, vent flaps behind the bumper, or even the seam by the rear glass. But 9 times out of 10, that roof rail is the culprit—now go show that gutter who’s boss!

Good luck, may your boot stay drier than a Honda engineer’s sense of humour!

seat ateca water in boot possibly from behind the rear wheel sound insulation "What can I do"