Minnesota Legislature
Office of the Revisor of Statutes
Minnesota Administrative Rules
4715.1160 BACKWATER VALVES.
Subpart 1.
Where used.
Drainage piping serving fixtures that are located below the elevation of the curb or property line at the point where the building sewer crosses under the curb or property line, and above the crown level of the main sewer, shall drain by gravity into the main sewer, and shall be protected from back flow of sewage by installing an approved backwater valve, and each such backwater valve shall be installed only in that branch or section of the drainage system which receives the discharge from fixtures located below the elevation of the curb or property line.
Further, in every building hereafter erected or remodeled so that the erection or remodeling creates a new dwelling use which is located below the elevation of the point where the building sewer crosses under the curb or property line, all fixtures installed below such point shall be connected to a separate branch drain. Each such branch drain shall be protected by an approved backwater valve and a gate valve. The gate valve shall be located on the sewer connection side of the backwater valve.
Further, the backwater valve and gate valve may be waived by the administrative authority whenever the sanitary sewer does not receive any storm water drainage and the building is located at a sufficient height above the public sanitary sewer so flooding by backflow will not occur, in the opinion of the administrative authority.
Subp. 2.
Construction of backwater valves.
Backwater valves shall be constructed so that a mechanical seal against backflow will be provided. Backwater valves shall have all balls or bearing parts of noncorrodible material and shall have bolted covers and be readily accessible for cleaning.
Subp. 3.
Venting of backwater valves.
Where the installation and operation of backwater valves interfere with the proper ventilation of the plumbing system, additional vents shall be provided so as to assure adequate ventilation of the plumbing system when the backwater valves are in a closed position.
Subp. 4.
Accessibility of backwater valves.
Backwater valves shall be installed so their working parts will be readily accessible for service and repairs. If installed substantially below grade a manhole with flush manhole cover shall be provided.
History:
19 SR 590; L 2007 c 140 art 4 s 61; art 6 s 15; art 13 s 4
Published Electronically:
May 14, 2012
Official Publication of the State of Minnesota
Revisor of Statutes