I need advice on a plumbing code question. My existing 1st floor
bathroom vanity appears to use the drain from the 2nd floor toilet as
a vent stack. Appears that both 1st and 2nd floor toilets have no
other fixtures draining into their respective drains.
Question: does the plumbing code allow me to route the 1st floor
vanity drain into the same drain from the 2nd floor toilet (which is
being used as a vent for the same vanity)? Or must I continue to have
a dedicated drain for toilet?
See sketch at:
(If this is not the appropriate way to reference an image on this
newsgroup, please advise and I'll change).
Your comments are appreciated.
re: Aren't wet stacks only allowed on the same floor?
I hope not! My 2nd floor bathroom, 1st floor sink and 4 basement
fixtures (full bath and utility sink) all use the same wet stack.
There are no dedicated vents for any fixtures in my house.
The 1st and 2nd floor fixtures drain into the cast iron vertical stack
and the basement fixtures all connect to the cast iron drain pipe
under the slab. Everything works fine as far as I can tell. The only
drainage problems I've ever had in 24 years were caused by roots in
the town owned section of the drain out by the street.
I had the same setup and was required to update it to current code when I did
some renovation last year. I had to move the downstairs vent so they connected
into the stack above the point where the upstairs waste tied into the stack, so
that water from above could not flow past the vents. It can be a small vent, I
ran 1 1/2" PVC alongside the stack and reconnected in the attic.
On Thu, 01 Nov 2007 06:11:00 -0700, anthonymmfalcone wrote:
If you are unable to extend vent to roof or above 2nd floor toilet,
consider using a mechanical vent installed at the sink. Just remember to
keep it accessible for inspection and maintenance.
Although not the best solution, it will work and may be permissible.
Good question to ask your local plumbing inspector. Sometimes codes vary
from locale to locale.
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