MULTICRETE™ II Filter Underdrain


Accessible MULTICRETE™ II Filter Underdrain

MULTICRETE™ II Underdrains provide a high quality, low cost, engineered product that is economical and versatile. MULTICRETE™ II Underdrains provide a low headloss underdrain with plenum access. MULTIWASH™ backwash is possible using this system.

The MULTICRETE™ II underdrain is a monolithic cast in place underdrain with open plenum design. It can be designed for media retaining or support gravel applications. Special nozzles allow for combined air/water backwash or water only backwash.

The accessible MULTICRETE™ II underdrain allows interior inspection after installation. The open plenum design provides for uniform distribution at high rates of air and water during backwash. It readily combines with the unique MULTIWASH® baffle to provide unlimited air-water backwashing. MULTICRETE™ II is NSF Standard 61 approved.


  • Corrosion resistant materials
  • Open plenum design
  • Media retaining design
  • Monolithic formwork construction


  • Long product life
  • Lower headloss
  • Greater hydraulic capacity
  • Access to underdrain
  • Eliminates support grave
  • Reduced filter depth
  • Fewer people needed to install
  • Structural strength with few joints