Can kitchen plumbing run behind cabinet and not in wall?
Normally, plumbing (drain and supply) runs inside wall, but is it permitted, by national building code, to run plumbing between wall and cabinet not inside wall?
This means moving entire row of cabinet forward ~2" as well as horizontal run of supply/drain/vent (not shown but very important). This drawing is simply to illustrate the cavity in which I want to run plumbing, not the full plumbing layout.
Question from user codechimp at stackexchange.
Answer:
No code issue with it. Well, other than - your drawing does not incude a required vent. But as to in the wall or in front of the wall, code does not care.
You have updated to indicate that a horizontal run of vent is intended in the space behind the cabinets. That would be a code violation, as both UPC and IPC require that such runs of vents be at least 6" above the flood rim of fixtures served (or similar language) and the flood rim of a sink in a countertop is at countertop level, with this vent pipe located below that level. Apart from the special case of "Island Venting" with its own set of rules, that is strictly forbidden.
A waste of space if you're leaving a gap behind all the cabinets to make room for plumbing behind one, and the sort of "dead space" that often attracts unwelcome guests.
You can simply run the plumbing through the bottom (and upper back for the vent, typically) of the cabinet, rather than running it behind.
Answer from user Ecnerwal at stackexchange.
Normally, plumbing (drain and supply) runs inside wall, but is it permitted, by national building code, to run plumbing between wall and cabinet not inside wall?
This means moving entire row of cabinet forward ~2" as well as horizontal run of supply/drain/vent (not shown but very important). This drawing is simply to illustrate the cavity in which I want to run plumbing, not the full plumbing layout.
Question from user codechimp at stackexchange.
Answer:
No code issue with it. Well, other than - your drawing does not incude a required vent. But as to in the wall or in front of the wall, code does not care.
You have updated to indicate that a horizontal run of vent is intended in the space behind the cabinets. That would be a code violation, as both UPC and IPC require that such runs of vents be at least 6" above the flood rim of fixtures served (or similar language) and the flood rim of a sink in a countertop is at countertop level, with this vent pipe located below that level. Apart from the special case of "Island Venting" with its own set of rules, that is strictly forbidden.
A waste of space if you're leaving a gap behind all the cabinets to make room for plumbing behind one, and the sort of "dead space" that often attracts unwelcome guests.
You can simply run the plumbing through the bottom (and upper back for the vent, typically) of the cabinet, rather than running it behind.
Answer from user Ecnerwal at stackexchange.