Interpretation #6817

Published August 17, 2011

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Original Request

Code Version
2007
Code
PLUMBING
Code Description
Plumbing
Chapter
6
Section
608.1
Topic
Water Supply Protection

Question

Is it the intent of the code to protect the water supply system only in an R-2 type occupancy or to protect a dwelling unit from another dwelling unit?

Answer Published 08/17/2011 at 4:40 PM

The intent of 608.1 is to protect the potable water supply
from non-potable cross-connections in general. Non-potable
examples would be fire sprinkler piping and irrigation
piping. Other specific requirements are described in 608.2
through 608.17, inclusive. The water piping in every
dwelling unit in a multifamily residential building is
potable. There is no need to protect one potable subset
from another potable subset in the same building.

Commentary

A properly installed plumbing system is protected at each fixture by air gaps or built in backflow protection. This alone would negate the need for internal protection at each unit water supply.