Tens of millions of microorganisms could easily be living in every square foot of carpeting. Included in this sea of life are mold, mildew and dust mites-all quite common allergens. Conventional portable vacuum cleaners have such inefficient filters that they simply blow the fine dust and tiny creatures back into the room. A central system with an outdoor exhaust is more powerful and it won't recontaminate the house. If carpeting has gotten wet, in a flooded basement for example, it can be far too moldy to try to salvage.
Replacement is often the only option because biologicals thrive in wet carpet.
There have been studies that have found an association between recently shampooed carpeting and Kawasaki disease in children. Kawasaki disease is characterized by a high fever and while its exact cause isn't known, wet carpeting seems to be a contributing factor. At those prices, a homeowner can have a beautiful solid oak floor accented with Oriental or native American rugs. The natural fiber rugs are easier to keep clean, and they will last far longer than carpet. Even after adding installation costs, they are often n the same price range as a medium priced carpeting, and they are far healthier.