Click Here For 3″ and 4″ Valve Installation Instructions



  • Slide collar through 8” riser pipe.  If collar does not slide freely through pipe, check to see if pipe is “out-of-round”.  If so, replace 8” riser pipe.
  • Check with your local plumbing agency to insure that threaded adapter and plug is acceptable.
  • Typically all backwater valves require adequate drop between the flood rim of the lowest fixture and burial depth of the valve in order to function properly.  A minimum slope of 1/8” per ft. is recommended.
  • 2-6” & 1-8” PVC bushings are enclosed for your use if needed.  Please discard if not used.
  1. Install the valve body in the sewer lateral with the “FLOW” arrow on the body pointing downstream.  Use approved solvent cement as per the manufacturer’s recommendations.   
  2. Rotate the valve body until the 8” opening is facing directly upward.  A level may be used across the top of the valve body to verify horizontal positioning.
  3. Cut the 8” riser pipe to the required length.  Insert and cement while keeping the inside of the body clean of debris.
  4. Cut the 4” insert pipe to a length (3-1/2”) shorter than the uninstalled 8” riser pipe.
  5. Cement the flapper assembly to one end of the 4” insert pipe.
  6. Cement the collar to the other end of the 4” insert pipe.  Align the center of the finger hole with the center of the flapper on the opposite end.
  7. When cement is dry, gently slide the 4” insert pipe – flapper assembly first – into the 8” riser pipe with the flapper facing the inlet side of the valve body.  Slowly lower the 4” insert pipe until it rests on the seating area of the valve body.  Seat the flapper assembly by rotating as necessary until it locks in place.  Visually inspect that the flapper assembly is installed correctly.  
  8. IMPORTANT: Prior to installation of the 8” threaded adapter (with the 4” insert pipe properly installed) cut a reference notch into the 8” riser pipe.  This saw cut notch should be aligned with the molded notch in the top collar.  For future removal, alignment of the notches will quickly indicate that the flapper is seated correctly.
  9. IMPORTANT:  Tighten the ¼” Stainless Steel thumbscrew until it seats snugly against the 8” riser pipe, fixing the 4” insert pipe in place.
  10. Cement the 8” threaded adapter to the 8” riser pipe to complete installation and screw the 8” threaded plug into the threaded adapter.

CAUTION:  Be certain that excess solvent cement has not impeded proper seating of the flapper assembly insert or the proper seating of the flapper sealing surface.