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Question: 06-30 Code Section: 7 Date: 13 April 2008

OBC 2006 Reference: 7.1.5.3., 7.6.2.1., 7.7.1.1., 7.7.2.1.

 

Question: Recently a question has arisen concerning the use of greywater for hose bibs. 7.1.5.3. (2) clearly states where greywater may be used. In the Appendix, definition of a plumbing system, it says a system of piping that conveys water for the purpose of watering soil or landscaping is not part of the plumbing system. If such piping is contained within the home, should it not be considered part of the plumbing system? The group agreed that any municipal water distribution system would require protection but, our question is: "Can a hose bib be supplied from a cistern with non-potable water or another source that contains non-potable water and has piping inside a residence?"

Interpretation: Grey water means sanitary sewage of domestic origin that is derived from fixtures other than sanitary units. Sentence 7.1.5.3.(2) only permits storm sewage or greywater that is free of solids may be used for the flushing of water closets, urinals or the priming of traps (i.e. hose bibs supplied with greywater are not permitted). This opinion is based on the fact that, greywater is produced from fixtures (i.e. governed under plumbing) other than sanitary units. According to 7.6.2.1.(1) and (2), non-potable water from a non-potable water storage tank, or a storm water storage tank (ie. a cistern), for the purpose of lawn sprinklering without involving any water distribution piping, shut-off valves must be provided and installed on the inside of the exterior wall complete with a "non-potable water" warning sign posted adjacent to the shutoff valve, provided the non-potable supply pipe is marked in accordance with 7.7.2.1.(1) and the piping is independent of the potable water system and not interconnected in any way.

Officials may exercise their discretion on the acceptance or rejection with the proposed installation based on the Objectives and Functional Statement addressed by Code. Furthermore, a non potable water system shall not be directly connected to a potable water system unless the potable water system is protected by a proper backflow preventer as selected using CSA B64.10. As for the question, the answer is YES, but we draw the reader to 7.6.2.4(8) where it reads, “Buildings of residential occupancy within the scope of Part 9 are not required to be isolated unless they have access to an auxiliary water supply”. In the case where access to an auxiliary supply is present, backflow protection is required.

Interpretation: Approved at AMES 2008

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