Donaldson Water Absorption Filters


Donaldson® water absorption filters quickly and effectively remove free water from hydraulic or lubrication systems. Using super absorbent polymer technology with a high affinity for water absorption, Donaldson water absorption filters alleviate many of the problems associated with water contamination.

Problems from water contamination:


  • Donaldson water absorption filters

Donaldson water absorption filters are capable of removing up to 2 liters of system damaging free water and are available in sizes that fit many Donaldson and competitive filter assemblies

Features (Benefits)

  • Fast, efficient free water removal - (Greater uptime  & Fewer maintenance hassles)
  • Pressure drop indicates when to change filter -  (Longer component life & Lower energy consumption)
  • No downstream migration of super absorbent polymer -  (Longer oil life & Greater machine efficiency)


  • Hydraulic system reservoirs  
  • Lube system reservoirs
  • Multiple tanks
  • Gear boxes
  • Small storage tanks
  • Lube rooms



  • Typical lifetime efficiency: 95% by mass
  • >77% water removal in first volume change
  • 95% water removal in 7½ volume changes
  • No migration of super absorbent downstream


To estimate the number of filters of a particular model, first estimate the amount of water in your system using equation (1): where VH2O is the estimate of the volume of water in liters, Voil is the volume of oil in your system in liters, and ppm is the concentration of water in your system measured using Karl Fisher titration (usually found in your oil analysis report). 

Then calculate the number of filters required using equation (2): where N is the number of filters required and C is the maximum expected capacity of the filter from the table above. Make sure to use correct units as identified above.