I have an 02 Accord EX with sunroof that has developed a weird leak that saturates the floor on the front passenger side when the car is left sitting in heavy rain.

What is weird about this leak is that the water seems to be coming up from underneath the carpet. It is not entering the car via the sun roof or the door as the seat and carpet on the side remain dry. (I have previously experienced blocked drain holes in the sun roof - but that spills water into the passenger seat and leaves a noticeable puddle on the seat).

I have attached a picture of the situation and I have circled where the dampness seems to start from.

Any ideas on what is causing this?

enter image description here

2019 Update

Chris's answer that it is a problem with the sunroof drain pipe matches with what my mechanic recently said (and Chris beat me to answering my own question).

My mechanic also stated that it was not economically viable to replace that drain pipe given how much interior etc would have to be removed to in order to access it. I don't know if this is BS or not.

(minor rant) My mechanic's solution to the problem was to permanently block the drain pipe so that it doesn't leak water under the carpet. Given that my driveway slopes slightly to the right, this means that water now pools in the sunroof on that side and spills over the lip of the sunroof and pours onto the passenger front seat - resulting in the same problem. I found this solution of theirs to be spectacularly stupid and I have some choice words selected to say to them but I am holding back on that right now (end rant)

My current solution is to reverse the car into the driveway so that it now slopes to the driver's side and water drains out the drain pipe on that side (which doesn't leak)

I was already planning on replacing this car in 2019 anyway, so I am taking deep breathes and letting this issue go.

  • More than likely the AC drain is clogged. Commented Jun 4, 2018 at 20:39
  • @Pᴀᴜʟsᴛᴇʀ2 It only gets wet when sitting in the rain, even when not running.
    – Peter M
    Commented Jun 4, 2018 at 20:41
  • Gotcha :o) Little details. Check to ensure the cabin air filter is fitted properly (if it has one). Also, check the A/C drain, anyway. There may be something stupid which goes into the intake for the HVAC and through this drain. It's worth a check. Commented Jun 4, 2018 at 20:47
  • @Pᴀᴜʟsᴛᴇʀ2 I just watched a video on replacing the cabin air filter and it's a significant endeavor .. lol
    – Peter M
    Commented Jun 4, 2018 at 20:55
  • If you've never changed it, it's a good thing ... not only for the HVAC, but for your health as well. Should be changed every time you change the oil ... or ... thereabouts ;-) Commented Jun 4, 2018 at 21:34

1 Answer 1


The sunroof hose may be clogged. The escape for the hose is very near the floorboards.

  • Coincidently I my mechanic recently said the same thing when I finally took the car in for a service - and I was about to answer my own question but you beat me to it. My mechanic also basically said that it was not economically viable to fix/replace that hose due to how much work it would be to gain access (don't know if this is BS or not). My solution is park my car on a slope so that the opposite side is lower and water drains out that side instead - so far that has worked.
    – Peter M
    Commented Jan 2, 2019 at 12:59

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