The ASME Standard is a nationally recognized standard that establishes requirements for dimensions, performance requirements, connections, materials and finishes, testing and marking of backwater valves.

There are six basic types of Backwater Valves:

• Horizontal Backwater Valve: A backwater valve designed to be installed in a horizontal drain line incorporating an internal check member and manual gate valve to prevent backflow.

• Combination Horizontal Backwater Valve and Manual Gate Valve: A backwater valve designed to be installed in a horizontal drain line incorporating an internal check member and manual gate valve to prevent backflow.

• Terminal backwater Valve: A backwater valve designed to be installed at the discharge end of a horizontal drain line incorporating a check member to prevent backflow.

•  Combination Floor Drain and Backwater Valve: A floor drain incorporating an internal check member to prevent backflow.

•   Normally open Backwater Valve: A backwater valve designed in such a manner as not to interfere with the movement of the air in the drainage system.

•  Vertical or 90-Deg Backwater Valves: A backwater valve designed to be installed in vertical piping, such as downstream from a P-trap or a holding tank.  

   Manufacturers 
 

   Jay R Smith Mfg. Co.  

   Josam Company

http://www.josam.com/catalog/JOS/line/BW

   Mifab Inc.

   Tyler Pipe/Wade

   Watts Regulator Company

   Zurn Industries, Inc.