Carpet acts as a filter for the room it's in, trapping dust, pollen, pet dander and other airborne particles rather than letting them stay suspended in the air. That's useful, until the carpet becomes saturated and starts releasing some of it back with every footstep across the room.
Regular vacuuming helps, but it only removes what sits near the surface. Hot water extraction reaches further into the pile, physically removing the allergens and residue that a vacuum can't access, which is particularly relevant for households with asthma, allergies, or young children spending a lot of time on the floor.
It's a genuine, if often overlooked, part of maintaining decent indoor air quality at home, alongside things like regular ventilation and dusting. A carpet that looks clean can still be holding onto a lot that isn't visible.
