Hot Water Extraction - The new equipment being made today is mind boggling. The makers of cleaning equipment  understand the needs for working in commercial and medical facilities where safety and security are critical.  I can run my hot water extractor  from my vehicle or bring it inside, depending if closed doors are desired. Carpet is clean and dry quickly.

Low Moisture - Less water is used, so the cleaning solution is more concentrated.

Because there is less water run through the carpet you get a fast drying time. 

The weight of the machine gives a deep scrub of the carpets (picture a caked on stain on a pan where you deep scrub). 

The chemistry is the workhorse, it encapsulates (surrounds) the soils removed by the scrubbing and what isn't picked up in the bonnet will dry and is picked up the next time you vacuum, because it can't reattach to the carpet. 

I doubted this method until I watched it used and could see its effectiveness in hospitals. 

With so many people constantly on the carpets they stayed clean.

The carpets were tested for bacterial load and came back as clean as the big truck wet cleaning method.

Dry Clean Powder - for rugs which are dry clean only.

Treated Water Cleaning - I like the idea, but it's not practical, so I don't offer it. 

First a water softener is used to remove minerals from this water, then the water is treated with electrolysis and oxidation, this takes a lot of time and equipment. Good so far.

A limited amount of water can be produced, and must be carried to the jobsite.

Because vehicles can only carry a limited amount of this water its use is limited. 

This limits the amount available for each each carpet, and it's never enough.

This results in call backs for stains that come back. 

The stained spots get cleaned at no charge because you can see it; but all the carpet should be cleaned, not just the spots you see.