# W/C DFU question

Discussion in 'UPC Plumbing Code Questions' started by Mr. Larson, Nov 10, 2011.

1. ### Mr. LarsonNew Member

Joined:
Nov 10, 2011
Location:
Everett, WA
So, I have taken my residential test twice now, and I failed! I have done well on everything but the waste and venting portion. I am beginning to believe there is something I'm just not getting, or maybe there is a sneaky trick to the test. Anyways, I would like to know how many 1.6 gravity tank toilets can be put on a 3" drain, (private/public)... and how many flushometer valve toilets can go on a 3" drain, (private/public).

2. ### johnjh2o1Plumbing Contractor for 49 years

Joined:
Aug 9, 2009
Occupation:
Retired
Location:
South*East
I believe the answer to both is two on a horizontal and three on a vertical drain.

John

4. ### jimboPlumber

Joined:
Aug 31, 2004
Location:
San Diego
I believe the answer to both is THREE, from table 7-5

5. ### hjModerator & Master PlumberStaff Member

Joined:
Aug 31, 2004
Occupation:
Plumber
Location:
Cave Creek, Arizona
Three toilets, of any kind, on a 3" line. A fourth toilet requires that it be increased to 4" FROM that point on. However, if this is per the IPC then the answer could be anything, depending on the cheapest way to install it.

6. ### WinslowPlumber

Joined:
Dec 30, 2005
Occupation:
Plumber
Location:
Hawaii
three on a horizontal line and 4 on a stack, according to the UPC

7. ### mtcumminsIn the Trades

Joined:
Jun 25, 2010
Occupation:
General Contractor/Property Manager
Location:
Pittsburgh PA
Well I think its 4 and 4.

Haha, no its not. Just amused that every post was a different answer. Pretty sure that 3 on horizontal 3" line is correct, but I have no idea on a vertical/stack. If I remember right, this horizontal setup would require one 2" vent between the first (furthest from stack) and second toilets, but I could be wrong (pros, please correct me if I am). I don't ever deal with situations like that, all my multiple toilet situations are stacked vertically (we city people build up, not out )

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