Vertical distance of kitchen sink p-trap matter?

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Hello. A new kitchen sink was just installed in an apartment that our family owns. I installed drainage pipes to connect the drain on the new sink to the existing drainage pipe that goes into the wall (then goes outside).
It's the first time I've ever done plumbing so it was a bit of a learning experience. I noticed after it was done that I could have shortened the vertical distance of the amount of water in the p-trap by about 2.25". The vertical distance of the water in the p-trap is 7" when I could have made it about 4.75".
This apartment unit is not rented and is kept vacant so that family members can stay there when they come to town. My 82 year old mom, who's in good shape, will stay there overnight about once a week. I mention this to give an idea how long the water will be staying in the p-trap.
Is a vertical distance of 7" of water in the p-trap too much if the kitchen sink will only be used about one day a week? Will that much water cause odors or attract mosquitoes? Should I shorten it to 4.75" to avoid those possible problems? Finally does anyone know if this is addressed in a plumbing code?
Thanks for any feedback.
Bill
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On Sun, 10 Jul 2005 22:51:36 -0700, Bill wrote

There IS more than one plumbing code, however the Uniform Plumbing Code limits trap seals to a minimum of 2 inches and a maximum of 4 inches.
Doug
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"plumbguru2" wrote

Thanks Doug. Great info you provided.
Bill
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I've known traps to stink but attracting mosquitoes seems unlikely to be a real problem. Any amount of water in the trap would tend to act the same. (petulance does not prefer deep water nor shallow water)
What you really want to avoid is having too small of a trap such that the water evaporates before you use it again, at that point sewer gasses can enter the house and really stink up the kitchen.
Too large of a trap and it may be more prone to clogging with debris or grease.
If you worry about the sanitary nature of the water down there, get in the habit of running the sink a few minutes and pouring a glass of lysol (or similar) in the trap before you vacate each week.

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"PipeDown" wrote

Great info Pipedown. Thanks so much.
Bill

learning
made
good
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"Ned Flanders"
I sort of wondered what he meant by the 7", but I assumed he was talking about the tailpiece. If not, then a DIYer strikes again.
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Hmm, Wonder if he is talking about the vertical drop before the trap. In this case, the distance shouldn't matter as long as the trap is spec.
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"PipeDown" wrote

talking
The 7" referred to the vertical distance from the lowest point on the midline of the trap to the midline of the pipe going into the wall. Based on the very helpful comments I have received on this ng (thanks!), I am going to remove a small vertical section (see my other post in this thread that I just sent for all the details) so what was 7" will be about 4.5" when it's done.
I measured the vertical distance in the bathroom trap and that was about 4" so I figure 4.5" should work.
Thanks for the feedback.
Bill

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"Bill"
We've gotten lost in all your details. From what it sounds like, you should have been able to simply buy a tubular P trap and installed it. Traps are specifically designed not only to hold a water seal, but to be self-cleansing. When someone manufactures his own trap, the danger is that it won't flush the water through.
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sorry cant understand you. bottom line..trap will controll amount of water unless trap is down hill of mail drain. the trap (the weir of the trap) has to be above the hole in the wall where drain exits.

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"Ned Flanders" wrote

Sorry I wasn't clearer. I just did another post where I tried explaining it again, hopefully it's more clear on that post.

of
I probably didn't realize the importance making sure the straight part of the pipe that connects to the pipe going into the wall has a definite downward tilt to it so gravity can do its thing. Thanks for emphasizing that.
Thanks for the feedback.
Bill

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"Mike Grooms" wrote

I probably made it a lot longer than necessary but I wanted to be thorough. Here's hopefully a better explanation:
A new sink was installed and the drain location on the new sink is different than the original sink drain location. At the new sink drain, a new straight drain pipe (pipe 1) will go down from it.
Attached to pipe 1 will be pipe 2, which contains the 180 degree trap section, so water enters pipe 2 in a down direction and exits pipe 2 in an up direction.
Attached to pipe 2 will be pipe 3. The end of pipe 3 to be connected to pipe 2 has a 90 degree turn. So water enters pipe 3 going in an up direction, then turns 90 degrees into a horizontal direction (actually slightly downhill direction), then goes in a straight (horizontal) direction for about 8" (the length of the straight portion of pipe 3).
The straight end of pipe 3 connects directly into the existing horizontal pipe going into the wall.
I had had a little 2" section of pipe between pipe 2 and pipe 3 which I will remove. This will decrease the trap length by 2". I'm defining trap length as the (vertical) distance from the bottom of the trap (at the centerline) to where the drain water begins flowing in an almost horizontal direction (at the centerline of that pipe) - the location on pipe 3 just after the 90 degree turn.

I can't have pipe 2 and pipe 3 be one pipe (meaning a pipe containing both the 180 degree trap and the 90 degree turn).
Here's why: if I use such a pipe, there's no way to get the drain water flowing out of pipe 3 to go directly into the existing pipe going into the wall. I would have to use 45 or 30 degree sections at the end of pipe 3 to connect the end of pipe 3 to the existing pipe going into the wall.
By rotating pipe 2 (the trap pipe) at the pipe 1 - pipe 2 interface and pipe 3 at the pipe 2 - pipe 3 interface, I can line up pipe 3 so it goes directly into the existing pipe going into the wall.

that
Well I don't have a choice in making the p-trap consist of two pipes rather than one (for the reasons I stated above).
Your last comment has made me realize the importance of making sure the water is flowing downhill so it can enter the pipe going into the wall. This means I have to make sure the straight part of pipe 3 (the pipe that connects to the existing pipe going into the wall) is slightly downhill, not horizontal. Thanks for emphasizing that.
Thanks for the feedback.
Bill

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I am sorry I could not make it any more clear than I already have. You dont want that answer I guess. You want to go on with your terrible description of your plumbing and hopefully get someone to say you have done the right thing. It is a very very simple answer. If you can remove a small bit of pipe and change the amount of water the trap holds then you have certianly botched the install. There is no way around this , sorry. If your new sink is much deeper then you might be shit out of luck and need to replumb the whole drain. A drum trap will buy you a couple of inches.
just currious but are you a liberal?

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"Ned Flanders" wrote

I understood you just fine but you apparently didn't understand me. I was trying to change that but apparently you didn't understant the second explanation. You never said what it was I wrote that was confusing you.

I understand the drainpipe going into the wall (and the straight portion of the pipe connected to it) has to have a downward tilt. I am quite aware of the phenomenon of gravity.

If the words "180 degrees" or "90 degrees" confuses you, consult a dictionary.

You sound like a paranoid person.

and
Sorry but that's absurd. The configuration I'm using (with the 2" pipe gone) is apparently a common configuration since that's how the plumbing is done under my kitchen sink and under the sink in the bathroom I just checked (both of which were not done by me - I don't know who did them - but both have worked just fine for many years).

need
No need for that - gravity is still in effect.

Sure am and proud of it.
Bill

an
horizontal
centerline)
direction
both
the
to
be
that
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"Bill the alleged liberal" wrote:

Man! I've been gone too long. I finally get some time to come back for a visit and the hottest discussion here is with a left wing DIY'er? :>))
I haven't read every word of every post in this thread (I got a lot of catching up to do) but the guys here are telling you straight. The "180 degree thingamajig" you are referring to is called the "J-bend". The "90 degree whatchamacallit" is called the "waste arm". There should be NO piece of pipe between the two. Either lengthen shorten the tailpieces from the sink. Period.
Bob Wheatley
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Bobby!!
You're back! I thought you wuz dead.
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Nah. :>) I just got sideways with a couple of really large projects and between project management and chasing no paying general contractors down for money I just had no time. I'm doing a little "restructuring" (see: downsizing) and hopefully life will return to something a little more "normal". Whatever that is for a plumber........:>)
Bob Wheatley
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money
AHA ! Dog the Plummer !

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"Bob Wheatley" wrote

was
Well some guys are. Ned is more interested in a political rant. He should go to a political ng for that noise.

I've said at least twice that that 2" section is not going to be there. Thanks for the info anyway.

It got shortened.
Bill

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got ya...light the fuse and stand back. its like pokin at stuff with a stick...funny :-)
libs are sooo easy to piss off.
BTW the job you did is still wrong. And I guess i am hostile agian for telling you that you made a mistake, that you are wrong.
Are you plae with a very red face??? FAt??

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