Why do I pre-vacuum?
Industry analysis has estimated 74% - 79% of the soil in most carpet is "Dry particulate matter" and in most cases can be effectively removed by a thorough dry vacuuming.
For this reason the "STANDARD for CARPET CLEANING", written by the Institute of Inspection, Cleaning, Restoration Certification (IICRC) states that: 'prevacuuming is the first step in any cleaning method.'
Because this most important step in the cleaning process can be VERY TIME CONSUMING, most cleaners, not even excluding actual certified cleaners, either skip this step totally, or simply breeze through the motions. When this occurs the remaining dry particulate will be hit with water and then transformed into a wet particulate (commonly known as MUD). After the cleaner has left your house and as your carpet dries, this "mud" begins to wick up the carpet fibers (like candle wax up a wick) to the carpets' surface. And you wonder why some of those spots came back?
Here at Happy Carpet Cleaners, up to half of the time on a service call can be spent on this step alone! This is why I claim you won't just Think you're carpets are clean, you'll Know it's clean!