When an RO system produces stops producing water, or produces water very slowly, the first things to check are the pre-filters and membrane. This video shows the process for checking whether the issue lies in the pre-filters or the membrane element. It is important to first shut off the water supply to the RO system and convey any disconnected tubing over a bucket or floor drain since there is usually still water present in the system. If you find that you do need new filters or membrane, they can be purchased online.