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.


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Challenger Water Filters ®

Challenger Water ® Conqueror & Gladiator Compatible Replacement Water Filters, TFC Reverse Osmosis Membranes, DIY Replacement Parts and HELP Guides.

Conqueror III & Gladiator III 5 Stage RO System

Conqueror II & Gladiator II 4 Stage RO System

Conqueror & Gladiator 3 Stage RO system


Challenger Guardian  T-560

Challenger Classic

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.

* Challenger is the registered trademark of Challenger, the manufacturer of Challenger brand drinking water system filtration equipment.  The replacement water filters and reverse osmosis membranes listed above are not manufactured or endorsed by Challenger  Rather, these replacement filters and RO reverse osmosis membranes are manufactured by other companies.  While these filters and reverse osmosis membranes are compatible for use in Challenger under counter reverse osmosis water filtration equipment, we make no representation as to whether using these water filter cartridges and RO reverse osmosis membranes is consistent with the warranty and specifications applicable to Challenger under sink drinking water system equipment.