The phrase “steam cleaning” distinguishes a water-based method of cleaning carpets from dry chemical compound methods used by some professional companies. It’s not the steam that cleans the carpet, though: it’s the detergents applied with the machine which the steam (or hot water) activates. This is true when you rent or buy a machine, or when you hire professional steam cleaners to do it for you. Even dry chemical cleaning companies use a small amount of water!