Rainsoft Ultrefiner UF50 Three Stage RO System


If you own a Rainsoft Ultrefiner UF50 Three Stage RO System, we sell generic compatible filters, parts, and replacement kit bundles to make changing filters easier. The Rainsoft Ultrefiner UF50 RO system was used prior to 2013 and was the last system by Rainsoft to allow generic replacement filters. The Ultrefiner UF50 features 3 stages with a 5 micron carbon block pre-filter, a 50 GPD TFC membrane, and another 5 micron carbon block as a post filter. This 3-stage RO system uses the carbon block pre-filter to reduce sediment, chlorine, and chlorine by-products before the membrane filters out impurities larger than .001 microns. The carbon block 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 – RO Membrane TFC 50 GPD (TFC-RS9-50 - Rainsoft Part#: 18644, 9568, 18571, 12447, 21176, M-T1810R50) – Replace Every 24 Months
  • STAGE 3 – Carbon Block Post Filter (OMB934-5M - Rainsoft Part#: 18557 or 9557) – Replace Every 12 Months

PDF iconRainSoft Ultrefiner System Manual