Hello. I recently had a post about a water leak in one of my jeeps. Turns out some water leaked from around the heater core from the engine bay whenever you washed it or something. When I had the carpet out, everything looked fine. However, on some areas there were patches that were the color of rust but were smooth, mostly along where the side trims are. Should I be worried about anything? I should also mention the padding under the carpet was brownish. Just old mildewed water or?

 

If I were you I would sand down those spots and then spray bedliner all on the inside of the boards just to be safe. Cherokees are known for rusting out so just stop it while you still can. My floor boards are a nightmare. I wish I did something sooner lmao.
As for the carpet, it is an old car and previous owners more than likely spilled things here and there so that could be the reason for the color. Or like you said, old mildewed water. I wouldn't stress about that.
Hope I helped :-)
peace