top check backwater valves backwater check valves backwater valves adapt-a-valve information ml fr4 fio valve information termex valve information straight fit backwater valves backwater valve diagram backwater valve features and specifications backwater valve history testimonials backflow prevention information helpful links backwater valve pricing frequently asked questions backwater valve specifications backwater valve installation tips backwater valve animation backwater valve videos contact us backwater valves main page backwater valves backflow prevention links


our backwater valves feature clear plastic tops for easy inspection
Our award-winning, patented, Mainline fullport backwater valves have clear plastic tops so you can visually inspect for blockage BEFORE problems arise!

Model # PE 2013 Access Box
Model # PE 2013
Valve Access Box

The overall width of the open base of the black PE 2013 Access Box is 14-7/8" X 20" and steps down to 11-1/8" X 14-7/8" at the top of its 16" height. The removable gray high density polyethylene (plastic) top access panel is 10-7/8" X 14-1/2". The access box top is held in place by two 1/4" Plastic Push Fasteners.

  • These Older Mainline Model # 4963 A (ABS) & Model # 4963 P (PVC) full port backwater valves can be retrofit with the TOP CHECK CONVERSION KIT to convert them into Top Check Valves.

  • top check conversion kitClear Top for easy visual inspection.

  • Fullport (normally open) non flow-restricting design.  It's virtually self-cleaning!

  • No problems with Blockages.

  • Gate closes automatically when sewer starts to back up

  • Built in main sewer cleanout.

  • Cleaning rods do not destroy the gate when feeding or retrieving cleanout cables.

  • Normally open design allows the free circulation of air throughout the plumbing system to the municipal sewer system.

  • New, Award-Winning Technology.

  • Affordable building drain backup protection.

  • Backwater Valve US Patent # 5406972

  • Backwater Valve Dimensions: Width: 10" (254 mm), Length: 15.5" (394 mm), Height: 11" ( 280 mm ).

backwater valve pricing

cutaway view of the model 4963 A or 4963 P backwater valve
Cutaway view of our Model # 4963
main line full port back water valve

More detailed backwater valve specifications

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adobe acrobat pdf filesAdapt-A-Valve Brochure (Adobe Acrobat pdf)

Adapt-A-Valve Inspection Chamber

Backwater Valve Diagram
Backwater Valve Features
Back water valves information
Backflow Links
Backflow Preventers
Backwater Valve Animation
Backwater Valve Videos

Basement Drain Backing Up

 contact us about your backwater valve needsContact Us

Flood Alarm

Frequently Asked QuestionsBack water valve questions

adobe acrobat pdf filesFullport Backwater Valve Brochure (Adobe Acrobat pdf)

how to install your backwater valveINSTALLATION TIPS;  how to install backwater valves 

Termex Backwater Valves
Termex Backwater Valve Brochure (Adobe Acrobat pdf)

NEW: TOP-CHECK BACKWATER VALVESnew Top-check backwater valves

Mainline ML-FR4 Backwater Valve (Fio Valve)
adobe acrobat pdf filesML-FR4 Mainline Backwater Valve Fio Valve Brochure (Acrobat pdf)

6" Backwater Valves - Mainline STRAIGHT FIT Backwater Valves

Mainline History

backwater valve measurements and specificationsMeasurements, Specifications and IAPMO Certifications


Mainline Fullport Backwater Valves offer the right solution for your sewer backup problems.


Protect Your Home with a Backwater Valve

All Orders must be placed ONLINE by Credit Card


telephone For non-order info, you may phone Greg at 330.836.9393 9 AM - 4 PM EST M-F
or Voicemail anytime)


copyright 2004 to 6/16/2024 at 12:4:56 ET,
Akron, OH, USA.
All rights reserved.

backflow prevention links is independently owned and resells products produced and manufactured by Mainline of Canada and assumes no liability for the installation of backwater valves and related products.

Be sure to check with the plumbing authority in the municipality in which your valve is to be installed to insure that your installation is in compliance with local code, and be sure have your valve inspected by your local plumbing inspector after installation. Inspect your valve frequently; the Backwater Valve through its clear plastic housing top, and the Adapt-A-Valve, by removing the gate cassette.


Pipe end-to-end, the Adapt-A-Valve takes up 6" of run in your line and the outlet is 1-1/2" LOWER than the inlet, so in just 6" the level of the pipe at the outlet side needs to be 1-1/2" lower.

Pipe end-to-end, the Backwater Valve takes up 12" of run in your line and the outlet is 3/4" LOWER than the inlet, so in just 12" the level of the pipe at the outlet side needs to be 3/4" lower.

Depending upon the amount of slope in your line (2% minimum is required for proper operation), you may need to replace several feet of pipe downstream from the valve to average out this "loss" of fall.

NOTE: New Straight-Fit and ML-FR4 require less slope. (refer to detail pages for these products)


Mainline Valve Warranty
(in printable Adobe Acrobat .pdf file)

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