Interpretation #7495

Published May 19, 2015

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Original Request

Code Version
2010
Code
PLUMBING
Code Description
Plumbing
Chapter
7
Section
715
Topic
Backwater valve

Question

Is it the intent of this section not to allow discharge through a backwater valve when the fixture rims are substantially above the upstream manhole? Can a utility district require one in this situation, contrary to the code?

Answer Published 05/19/2015 at 8:04 AM

Yes, it is the intent of the section as that is exactly
what it states.

Commentary

However, the connection to a public sewer system is subject to a contractual agreement and under the control of the provider. The purpose of a backwater valve is to protect fixtures from a backup of the public sewer. Only fixtures that are at a lower elevation than the next upstream manhole cover are at risk. Plumbing fixtures that are not subject to backflow are not permitted to discharge through a backwater valve. By limiting the fixtures that discharge through a backwater valve, you limit the amount of backup from any upstream fixtures when the public sewer is blocked. The valve will also be protected from excess wear and tear and failure from debris. That being said, the public utility has the final word.