Do carpets get dirty quicker after a carpet cleaning?
The answer to that is yes and no. Carpets will get dirty quicker if the carpet was improperly cleaned. A proper cleaning will not cause your carpeting to re-soil any faster and will greatly extend the life of your carpets.
What is an improper cleaning?
One way carpet is improperly cleaned is by the use of carpet cleaning chemicals which are not approved for use on stain resistant carpeting. Cleaners with too high of a PH can strip the protector off of a carpet. Household detergents should never be used for carpet cleaning as they are too strong and are not designed to be easily rinsed.
Poor extraction can be another cause of rapid carpet re-soiling. If the cleaner is leaving too much moisture in the carpet, then they are not removing as much of their pre-spray. This can leave a residue on the carpeting which will attract soil. This is also a reason why rental units do not work very well. They do not have as powerful of a vacuum as professional units and leave quite a bit of moisture in the carpet.
Improper rinsing can also cause carpets to get dirty faster. This is another area where rental machines come up short. The pre-spray detergent used on carpet should be thoroughly rinsed either with plain water, an acid rinse or a detergent rinse designed to not leave a residue. Rental units extract with a carpet shampoo or detergent, leaving residue behind.
How do you insure a proper cleaning?
Ask your carpet cleaner questions. Find out if they have had proper training in carpet cleaning. Do they use chemicals designed for carpets? Are they certified? Do they guarantee their work?
If you must use a rental unit, make extra drying passes with the machine. Also spray your cleaning solution on separately and extract the carpet with plain water. Then get the carpet dry as soon as possible by using fans.