It’s called “wicking.” The spot that was treated seeped back into the backing of the carpet and maybe even the padding. This happens most often with pet urine and any spilled substance in a large amount. When the carpet is cleaned, the stain is removed from the pile of the carpeting. As the carpet dries, the moisture settles back into the carpet and into the pile. So this is what makes the stains reappear sometimes, but it usually can still be removed. If this happens to you after your carpet cleaning, give us a call for the proper treatment. There is no need to worry about cost, thanks to our satisfaction guarantee.