MULTIBLOCK® Filter Underdrain

MULTIBLOCK Filter Underdrain

Versatile MULTIBLOCK® Filter Underdrain

MULTIBLOCK® Underdrains provide a high quality, low cost, engineered product that is economical and versatile. MULTIBLOCK Underdrains can be fitted with the unique Laser Shield™ media retaining system that eliminates the need for support gravel. Combined air and water backwash is possible using this system.

MULTIBLOCK underdrains deliver to you…

  • Reduced profile underdrain option
  • Superior media retention capability
  • Uniform distribution of water and air backwash

The versatile MULTIBLOCK Underdrain has been installed in concrete and steel gravity filters for a number of applications. Packaged treatment units as well as large cluster filters have benefited from the design. It readily combines with the unique MULTIWASH® baffle to provide unlimited air-water backwashing. Your old clay tile underdrains are ideal candidates for replacement with MULTIBLOCK underdrains which are NSF Standard 61 approved.


  • HDPE plastic construction
  • Snap together design
  • Gasket seal between blocks
  • Laser Shield media retention option
  • Dual lateral design
  • Integrates with MULTIWASH backwash


  • Lightweight
  • Corrosion resistant
  • Easy to handle and install
  • Easier to install
  • No lubricant needed
  • Corrosion resistant design
  • Eliminates support gravel
  • Minimizes depth required
  • Uniform distribution
  • Superior media clean
  • Unlimited backwash duration


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