Large selection of replacement water filters, reverse osmosis membranes, testing kits and water filter system repair parts. From one water filter or membrane to case quantity discounts.

LOW PRICES and FAST SHIPPING ONLINE SINCE 1999 !

99.5% Of All Items In Stock For Same Day Shipping!

RainSoft Water Filters ®

 

RainSoft ® Ultrefiner RO Compatible Replacement Water Filters, RO Reverse Osmisis Membranes, DIY Service Parts and HELP Guides for RainSoft Under Counter Reverse Osmosis Drinking Water Systems

Easy TDS Membrane Performance Calculator
See If It is Time To Replace Your Membrane

Simply enter your Feed Water TDS and RO Water TDS into the boxes above and click "Submit". The percentage of TDS Rejection will be displayed. We normally recommend membrane replacement once you drop below 75%. This may vary in areas with high TDS in the feed water.

See our selection of TDS meters under Water Tests


Be sure to check our Parts Department for important parts such as TDS Testers For Reverse Osmosis Membranes, Replacement Tanks, O-rings , Filter Housing Wrenches, Faucets, Pumps, Fittings, UV Systems and more parts for your reverse osmosis pure water filtration system.   View maintenance and servicing tips online at our Installation & Trouble shooting Guide.





 


* RAINSOFT® IS THE REGISTERED TRADEMARK OF RAINSOFT, THE MANUFACTURER OF RAINSOFT ® BRAND WATER TREATMENT EQUIPMENT.  THE REPLACEMENT WATER FILTERS AND REVERSE OSMOSIS MEMBRANES LISTED ABOVE ARE NOT MANUFACTURED OR ENDORSED BY RAINSOFT.  RATHER, THESE REPLACEMENT WATER FILTERS AND REVERSE OSMOSIS MEMBRANES ARE MANUFACTURED BY OTHER COMPANIES.  WHILE THESE REPLACEMENT WATER FILTERS AND REVERSE OSMOSIS MEMBRANES ARE COMPATIBLE FOR USE IN RAINSOFT ® BRAND DRINKING WATER TREATMENT EQUIPMENT, WE MAKE NO REPRESENTATION AS TO WHETHER USING THESE REPLACEMENT WATER FILTERS AND RO REVERSE OSMOSIS MEMBRANES IS CONSISTENT WITH THE WARRANTY AND SPECIFICATIONS APPLICABLE TO RAINSOFT ® DRINKING WATER SYSTEM EQUIPMENT.