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 LaserShield 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