There is no such thing as "dry" cleaning a carpet. All five major methods employ the use of moisture.
In a contest held by a consumer advocate in Denver, Colorado, four of the five major carpet cleaning methods were judged in a contest to see which method got an extremely soiled carpet the “cleanest”. The winner was clearly truck mounted hot water extraction.
In the consumer advocate’s summary comments, he said the reasons his panel chose hot water extraction as the winner were appearance improvement, because it dried the fastest and left the least amount of residue.
The answer is simple: When cleaning an extremely soiled carpet, if the job is to get the carpets as clean as you can,than with most methods you have to go over and over the carpet again and again. During this process, the carpet ends up wetter than it did with a “wet” cleaning method.
The drying time for truck mounted hot water extraction carpet cleaning depends upon the amount of soiling, the type of the carpet, downtime considerations, the ventilation in the building following cleaning and several other factors.
Your cleaning technician will discuss with you your drying considerations, but drying time will normally be within 1 to 12 hours.