Please critique this plumbing arrangement

[Arky217]

This is my proposed arrangement for the plumbing of my retirement house.
The outside walls are finished; no plumbing will be within them.
Also, I don't want to go through the metal roof, hence the venting out the gable end.

Although I'm in an area not subject to code, I would appreciate a plumber's
evaluation to make sure that I'm not making any major mistakes.

Sink #1 is the kitchen sink; #2 is the bath sink.
Of course, the bath sink, commode and tub are in the same room;
they're shown like they are on the sketch just for clarity in how the piping is run.

One thing I'm not sure of is the drain for the kitchen sink.
I don't know if the 66" is too long for the 2" drain pipe from the trap to the wall.

The dark 2" line down from the kitchen sink is another way that I could run the drain
and eliminate the 66" horizonal run, but I'm not sure if that is too much drop
and might empty the trap when a sinkful of water is drained.

Thanks in advance for your comments,
Arky

[Terry]

The kitchen sink may have too long of a trap arm. We're limited to 60" on the West coast for 2". We normally run 1.5" for the kitchen trap arm, max 42" long until the vent, and then 2".

The tub trap is normally in the crawspace, but what you have looks good.

The toilet and lav look fine with the lave being wet vented over the toilet with this exception. If you have a 3" line going out, then there should be a composite of a 3" line for venting. That could be two 2" vents and one 1.5" vent, Or it could be three 2" vents. If you add the venting now, it's two 1.5's and one 2" Changing to kitchen sink vent to 2" would fix that. Also the horizontal is too long for standard sizing. Upping the kitchen sink vent up one size to 2" for that long section is also wise.

Most roofs have penetrations anyway. Roofs need venting at the top and at the lower edges. My last house had a metal roof, and I had quite a few vents going through the roof. And roof vents, and skylights and furnace venting.

[kreemoweet]

Arky said: "I'm in an area not subject to code ... ". Sir, you are badly misinformed, Arkansas most certainly does have a plumbing
code, just have a look here: http://www2.iccsafe.org/states/arkan..._frameset.html. This code applies
to every square inch of the State of Arkansas.