Your sediment filter should be changed out every 12 months. This pre-filter stage is designed to strain out sediment, silt and dirt. This is especially important as the sediment filter protects dirt from getting to the delicate RO membranes. If you fail to change this filter on schedule, dirt and silt can reach the RO membranes which can then easily become clogged and foul. The RO membrane is the most expensive filter in the RO system, so it’s important to protect it. The semi-permeable RO membrane in your RO system is designed to allow water through, but filter out almost all additional contaminants. If you take care to replace the previous sediment and carbon filters on schedule, the RO membrane should only need to be replaced every two to three years. Of course the schedule will vary based on the quality of your water and household water usage. In a 10-stage RO System, a final post filter will “polish” off the water to remove any remaining taste and odor in the water. This final filter is a GAC (granular activated carbon) filter. The GAC filter ensures you’ll have outstanding drinking water. Failure to change out filters per their replacement schedule can not only cause damage to the system, but will also cause a decrease in water production. Thus, if you notice a decrease in water flow from your RO faucet, that may be an indication that your filters have reached the end of their life span.