Rainsoft 9590-T Three Stage RO System


The Rainsoft 9590-T 3 Stage RO system featured a 5 micron carbon block pre-filter, a 12 GPD TFC membrane, and a 5 micron granular activated carbon inline post filter, all of which we offer generic non-OEM replacements for. The Rainsoft 9590-T Three Stage RO System uses a carbon block pre-filter to reduce sediment, chlorine, and chlorine by-products before the membrane filters out impurities larger than .001 microns. The Granular Activated Carbon (GAC) post filter treats for taste and odor.


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 – Carbon Block Pre-Filter (OMB934-5M - Rainsoft Part#: 18557 or 9557) – Replace Every 12 Months
  • STAGE 2 – DISCONTINUED - RO Membrane TFC 12 GPD (TFC-RS9-12 - Rainsoft Part#: 12447, 13016, 9565, 9772, or M-T1810R12) – 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