Reverse osmosis parts such as replacement pre-filters and membranes are important elements to a properly functioning reverse osmosis system in your home. All residential reverse osmosis systems must have the pre-filter stages replaced regularly to ensure a high level of water quality and quantity. Not replacing the pre-filter stages at the proper interval can not only affect the water, but can actually cause damage to the reverse osmosis membrane further degrading the overall water quality. Most reverse osmosis manufacturers suggest that pre-filter stages are replaced at least three times per year. Reverse osmosis membranes are typically used for 3 - 5 year before being replaced. For reverse osmosis systems with an inline carbon filter, these are usually changed once per year. Count on aQuatell for all of your reverse osmosis filter, membrane, and parts needs.