Civic has had an eternal water leak on the passenger side footwell. But its getting so bad now that the carpet has mold on it.

I know I saw a DIY on this several years ago as this is a common problem but now I can't find it anymore - anyone have the link or a DIY on how to fix this?

I'm going to pull the carpet out anyway and put on some spray on bedliner either rattle can or herculiner because this particular civic we use for a lot of outdoor stuff so it is always muddy/dirty inside but if the water leak fix is easy I'd love to do that too...

 

There is a drain hose for the A/C evaporator located behind the glove box that can become clogged. Cleaning out this hose should fix the problem.

 

It could also be the heater core.