In high-pressure hot water extraction or “steam cleaning”, a carpeting cleaning service uses a pressurized manual or automatic cleaning tool to pass over the surface several times to thoroughly rinse all pre-conditioner, residue, and particulates.
Extraction is by far the most important step in this process. Since the hot-water extraction method uses much more water than other methods like bonnet or shampoo cleaning, proper extraction is critical to avoid oversaturation. When carpet is saturated, there is a risk that soils and residue from deep in the carpet fiber and backing will “wick” up to the surface, resulting in browning, or the carpet layers may delaminate.
Hot-water extraction generally involves slower drying times, lower production rates, and more labor-intensive processes than dry carpet cleaning. Drying time may be decreased by extra use of fans, air conditioning, and/or outdoor ventilation.
Rather than soaps, the steam-cleaning system uses detergent-based solutions that dry to a powder or crystal. The surface is dried to avoid saturation, typically taking 3–4 hours if done correctly. [An inexperienced carpet-cleaning service will sometimes over-wet carpeting, leading to mold and recurring stains; arising from the “wicking” effect, whereby deeper soils are water-driven upward along carpet fibers, thus reconstituting visible stains.] Some carpet-cleaning solutions are carbonated to dissolve organic material more effectively. Beyond these treatments, anti-staining and anti-soiling products can be applied by the carpet owner.