The Whirlpool UltraEase reverse osmosis replacement membrane WHEERM should be replaced every 1 - 2 years to keep the system working efficiently and to ensure the highest quality water is available for your family. This system is NSF certified and . All Whirlpool under sink drinking water systems employ patented UltraEaseTechnology allowing for easy filter change with no hassle or mess. This system also includes an EZ-Change Indicator Light that notifies you when it is time to change filters. Systems WHAROS5 WHAPSRO and WHER25 Whirlpool Reverse Osmosis Systems reduce or remove many contaminants including lead cysts dissolved solids chlorine taste and odor sediment arsenic pentavalent barium cadmium chromium vl chromium III copper nitrate nitrite radium selenium fluoride turbidity ammonium bicarbonate bromide chloride magnesium sodium sulfide tannin zinc and chemicals. Questions? Call the Whirlpool helpline at 866 986-3223.