Rainsoft 9590-C Three Stage RO System


The Rainsoft 9590-C is a discontinued 3 stage RO system that featured a now discontinued membrane style. The 9590-C was used circa 2000 and allowed for generic replacement filters. It featured a 5 micron polyspun sediment pre-filter, a since discontinued 10 GPD CTA membrane, and a 5 micron gradular activated carbon inline post filter. The Rainsoft 9590-C uses a sediment pre-filter to reduce sediment particles before the membrane filters out impurities larger than .001 microns. A Granular Activated Carbon (GAC) post filter treats for taste and odor. Because the required membrane has been discontinued, we highly recommend converting to the 5EZ50-RK to keep your old tank and spout with the same high quality water you expect.


Note: If your Rainsoft reverse osmosis system is from 2013 or newer, it most likely is the Ultrefiner II. The Ultrefiner II requires proprietary filters that must be purchased from a Rainsoft dealer. Conversion kits to generic non-OEM replacement filters are available.



  • STAGE 1 – Sediment Pre-Filter (93023 - Rainsoft Part#: 9547 or 9747) – Replace Every 12 Months
  • STAGE 2 – DISCONTINUED - RO Membrane CTA 10 GPD (CTA-RS9-10 - Rainsoft Part#: 9564) – Replace Every 24 Months - Recommend converting system with the 5EZ50-RK for continued use
  • STAGE 3 – Inline Carbon GAC Post Filter (CL6ROT33-BB - Rainsoft Part#: 9798 & 18718 *may require elbow fitting CI480822W) – Replace Every 12 Months