I would not worry about the stain on the back of the carpet unless it starts showing on the carpet. I would worry about a piece of plastic between the carpet and pad. There could be some moisture still in or under the pad which could mold.

Emma, the carpet backing stain continues to wick up to top of carpet.

Doubt there was any moisture because carpet was rolled back and dried via fans as well as the padding before plastic was put in place.

Maybe another steam cleaning will remove rest of carpet backing stain.

Krissie,

Call the Co, back and tell them U have Brown Out or Wicking. If they R good they will come back and take care of it. If they R not, this is the easiest way 2 handle it. I assume this is not an entire room? If they will B willing 2 come back, no problem. Everyone has a qt. spray bottle? 1/2 water and 1/2 White Vinegar. Rub it into the pile of the carpet and U will B fine. this is a low acid rinse.

I don't understand why you worry about the BACK of the carpet. Is the stain showing through to the top of the carpet? I WOULD, however worry about the plastic between the padding and the carpet. Even if there is not any moisture now, the first time you spill something or someone walks in with wet feet or..., you'll have moisture that can sit between the padding and the carpet and cause mold. Besides providing a nice place to walk or sit, the padding provides air to circulate throughout the area under your carpet. Yes, it gets dirty. Yes, that is normal and pretty much unpreventable. If you really hate this, maybe you should install tile or wood instead of carpet. Just a suggestion. I bet you have a beautiful and spotless home!

eteinne, Thanks for your suggestions. I do use half/half water and vinegar to clean the area, however the spot comes back in a couple of weeks. Also use a fan to dry.

It has been a year since carpet was cleaned, too long to expect them to come back for a redo. I kept thinking my cleaning and drying repeatedly would solve the problem.

grandmamaloy,

My concern is the same spot that keeps recurring on top of the carpet, coming up from the carpet backing. Getting the backing clean would be a way to stop the stain from wicking up.

Most carpet padding has a sheet of plastic bonded to the foam to prevent liquids from going into the padding. Over time the plastic breaks down and pulls apart allowing for liquids and dirt to sift through to the sub floor or concrete foundation. Using a plastic sheet replaces the plastic coating on the padding, serving the same purpose.

Carpet padding is used to add comfort, help carpeting to last longer, sound proof, and help keep carpet clean. The bonded plastic on foam padding would prevent air flow.

The room with stain is seldom used living room so it is unlikely wet shoes or spilled drinks would occur. Our large family likes being together in the den/family room.

The original problem was a leaking roof that dumped gallons of dirty water through the ceiling onto the carpet. Hail storms have a way of destroying roofs.

Thanks for the compliment, I do have a beautiful home, well maintained over the years but not spotless by any means! Homes are made to live in.