Carpet cleaners don't have pesticide licenses, so we can't claim to kill anything. That being said, if a flea survives what we do to the carpet, we've got bigger problems.
While professional steam cleaning (hot water extraction) can help eliminate fleas, it is not a substitute for pest control services. Fleas are very sneaky; when an infestation occurs, they likely are not just in the carpet. For comprehensive flea removal, professional pest control measures are necessary to kill fleas at all their life stages, including eggs, larvae, and adults. Having your carpets and upholstery professionally steam cleaned is an excellent idea after these measures have been taken to rinse away all the dead insects, chemical residue, and other unhealthy accumulated particles.