# Are toilets And Tubs self vented ?



## Cal (Jun 17, 2008)

What's your opinion ? Seems several of us on the threads have made reference to the thought that toilets are "self vented " . Not that i disagree ,, just want more explanation .

In that case ,,, i am under the impression that with an overflow hooked up does it make a tub self vented ???? 

Still think vents are needed after the traps ,,but this could make a nice heated thread :whistling2:


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## user2090 (Sep 26, 2009)

Neither are self vented. Code requires both to be vented after the trap. I have been in many homes that did not have proper venting, and the fixtures both did not drain that well. Have really noticed that problem with the newer low water toilets.


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## grandpa (Jul 13, 2008)

ALL fixtures are self venting in the respect that they are not closed...they are open to the atmosphere, and therefor will drain completely on their own. What the code requires is that the TRAP ARM be vented. Otherwise, the trap tends to siphon dry, both when it is used itself, and also by waste passing by on the lateral or stack.


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## SlickRick (Sep 3, 2009)

Fixtures are absolutely not self venting or they could not syphon. Without a vent downstream that allows air to enter the system to break the effects of gradient hydraulics ( hydraulic plug) You have a "S" trap formed. A w/c is the only fixture allowed to have a built in "S" trap due to the fact of the built in trap refill .


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## TheMaster (Jun 12, 2009)

I closed the vent for my toilet and it flushes fine. You can fill other fixtures and dump them all at once no problems. The vents not needed in my case other than to satisfy code and to keep other plumbers from jumping up and down saying..."it has to be vented". I posted some pics last year showing the vent sealed off.:laughing:


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## SlickRick (Sep 3, 2009)

Then you had a vent that was in reach to break the effects of gradient hydraulics.


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## TheMaster (Jun 12, 2009)

slickrick said:


> Then you had a vent that was in reach to break the effects of gradient hydraulics.


Not to the open air I didn't. That entire bathroom is revented back to that one 3" stack thats also serving the toilet. The only vent that was open was 30-40 ' away. I believe it was acting like a combination waste and vent....in other words the pipe never filled up enough create a siphon and air could travel above the water....and I did have an open vent way down the line to equalize the pressures between the pipe and the open air. So you are right that I did have a vent but I dont think it broke the siphon.....I dont think the pipe ever filled up enough to siphon.


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## SlickRick (Sep 3, 2009)

TheMaster said:


> Not to the open air I didn't. That entire bathroom is revented back to that one 3" stack thats also serving the toilet. The only vent that was open was 30-40 ' away. I believe it was acting like a combination waste and vent....in other words the pipe never filled up enough create a siphon and air could travel above the water....and I did have an open vent way down the line to equalize the pressures between the pipe and the open air. So you are right that I did have a vent but I dont think it broke the siphon.....I dont think the pipe ever filled up enough to siphon.


I will agree with that. If there is enough air in the top of the line it would have the same effect as a vent. But fixtures are not designed to be self-venting. A tub has a overflow not a designed vent opening. same for a Lav. KS has no extra holes at all. I know you know all this, Plumbing 101. :laughing:


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## PLUMBER_BILL (Oct 23, 2009)

slickrick said:


> Then you had a vent that was in reach to break the effects of gradient hydraulics.


I have seen in many older homes where not all fistures are vented. One main vent through roof off a bathroom. Cold weather "HOR FROST"
vent closed. Toilet will not flush.


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## Titan Plumbing (Oct 8, 2009)

I'm learning...I'm gonna sit back and have an Iced Tea..........thanks.


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## Optimus Primer (May 20, 2009)

we have no distance from the vent to the w.c. anymore.


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## Plumber Jim (Jun 19, 2008)

I have seen a numbr of cases were the vent for the toilet was clogged and the toilet would not flush properly untill i cleared the vent. I think some layouts will will give you more trouble than others if the vent it plugged.


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## SlickRick (Sep 3, 2009)

PLUMBER_BILL said:


> I have seen in many older homes where not all fistures are vented. One main vent through roof off a bathroom. Cold weather "HOR FROST"
> vent closed. Toilet will not flush.


The original distances and grade (fall) were determined by engineers that represented the Uniform Code body. I had a black and white copy of their glass pipe system that they used to come up with the distances for effective trap arm distances and grade percentage that would be effective. Now they have been modified to allow for the systems we use now. As long as there is enough air in the system, the effects are broken. But a "S" trap, will always be a "S" trap through physics.


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## Master Mark (Aug 14, 2009)

*they are actually self vented..*

in our state anything goes, the toilet can be 15 feet away from the nearest vent , and that is considered ok...... it does work ok...

the tub can run 10 feet or more over to a swet vent off a lavatory....

I beleive we use the cabo code here for most construction... it is the most lax code around 

so the whole 5 bathroom house can have just one 1 1/2 vent going out the roof...

I like to use both cabo and the old UPC....I dont like to run a 3 inch vent all the way out of the house cause you end up tearing up the walls and have bulges in the drywall 



I like to mix them up a little bit and make the inspector really think,,,.:laughing:


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## TheMaster (Jun 12, 2009)

slickrick said:


> I will agree with that. If there is enough air in the top of the line it would have the same effect as a vent. But fixtures are not designed to be self-venting. A tub has a overflow not a designed vent opening. same for a Lav. KS has no extra holes at all. I know you know all this, Plumbing 101. :laughing:


The only way I see a fixture being self venting is just the fact that its open to the atmosphere in that which the fixtures used. If you sealed the top of a fixture off and then filled it......it would not drain. I give a soda straw full of water with your finger over one end as an example of that.


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## Cal (Jun 17, 2008)

All good replies !! I totally believe in a vented system ! However there are times when we have all seen things that just don't make sense HOW THE F**K DID THAT EVER WORK ??!! 

Long as the integrity of the trap seal is maintained ,,, i don't care how it works !


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## SlickRick (Sep 3, 2009)

TheMaster said:


> The only way I see a fixture being self venting is just the fact that its open to the atmosphere in that which the fixtures used. If you sealed the top of a fixture off and then filled it......it would not drain. I give a soda straw full of water with your finger over one end as an example of that.


Yes it will drain in most instances,but if you had a clear straw and formed a "S" trap in it, when it drained would it have enough water in it to prevent air or gas from escaping? I am glad we are back on plumbing!


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## Optimus Primer (May 20, 2009)

just like for years our kitchens used to be 3 inch island drains. Being 3 inch it would vent itself. Now we have to studor our island kitchens.


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## SlickRick (Sep 3, 2009)

Master Mark said:


> in our state anything goes, the toilet can be 15 feet away from the nearest vent , and that is considered ok...... it does work ok...
> 
> the tub can run 10 feet or more over to a swet vent off a lavatory....
> 
> ...


As long as the pipe is sized correctly, it will vent at those distances. That is why they have modified the systems.


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## TheMaster (Jun 12, 2009)

When a toilet is flushed you can hear the siphon being broken at the end of the flush. Its not broken by the vent. The sound your hearing is the siphon being broken by the toilet sucking air from the room the fixture installed in. 

A toilet is suppose to have an automatic trap prime through a refill hose on the ballcock....BUT toto had a 1.6 design(maybe they still do) with a ballcock that didn't have a refill hose and didn't have mechanical means of re-priming the trap. It was approved because even without a refill the trap was re-primed by the residual water left over from the flush as it drained from the rim of the fixture. 

I suppose the code made an exception and they should have.....totos design didn't rely on mechanical means of re-primng the trap but rather on good design.


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## SlickRick (Sep 3, 2009)

TheMaster said:


> When a toilet is flushed you can hear the siphon being broken at the end of the flush. Its not broken by the vent. The sound your hearing is the siphon being broken by the toilet sucking air from the room the fixture installed in.
> 
> A toilet is suppose to have an automatic trap prime through a refill hose on the ballcock....BUT toto had a 1.6 design(maybe they still do) with a ballcock that didn't have a refill hose and didn't have mechanical means of re-priming the trap. It was approved because even without a refill the trap was re-primed by the residual water left over from the flush as it drained from the rim of the fixture.
> 
> I suppose the code made an exception and they should have.....totos design didn't rely on mechanical means of re-priming the trap but rather on good design.


I don't think it was an exception, but they demonstrated how their design would replenish the trap seal. More than 1 way to skin a cat.


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## TheMaster (Jun 12, 2009)

I went to a service call from new tenants in a home a few years ago. The complaint was the K-sink would drain forever if they ran alittle water but if they filled the sink up it would take almost 24 hrs to drain.

It was an island sink and was plumbed in dwv copper. It had a P-trap but it was acting as an s-trap because after the p-trap portion of the piping it had a 90 degree copper 90 that turned it down through the floor.

The house was 5 ' off the ground so I went underneath to check for a cleanout.
When I got under there i saw the problem.....No vent anywhere on that line AT ALL.
It came through the floor and when it got into the crawlspace it offset with a 45...about 3' and then with another 45 it turned down directly into the 4" cast iron.

The entire K-sink drain was vertical with no vent. It had a cleanout on the 1.5" copper K-sink drain in the crawl so I thinking its worked for 40 years.....and it just needs to be cleaned. I cleaned both ways and reinstalled the plug. Filled the sink up and it still wouldn't drain when you filled both sides of the sink up.

You could fill one side up and it would drain fine.....you filled both sides up it would not drain at all.

The home originally had a single bowl sink.

I installed a mechanical vent under the sink and it worked perfectly.

I suppose i could have also installed a branch off the drain in the crawl to the closest vent but I still felt without the mechanical vent to protect the trap it would drain but siphon and not create the seal........since the vertical distance was so great. From the rim of the sink to the 4" cast was a vertical distance 8-9'

I guess I could have done both the mechanical and the branch.....but I did not.


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## Cal (Jun 17, 2008)

TheMaster said:


> I went to a service call from new tenants in a home a few years ago. The complaint was the K-sink would drain forever if they ran alittle water but if they filled the sink up it would take almost 24 hrs to drain.
> 
> It was an island sink and was plumbed in dwv copper. It had a P-trap but it was acting as an s-trap because after the p-trap portion of the piping it had a 90 degree copper 90 that turned it down through the floor.
> 
> ...


 Had an almost exact situation in a circa 1940 house . I installed a mechanical vent and these two WONDERFUL Octogenarians thought i had cured world hunger . It was nice


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## Don The Plumber (Feb 14, 2010)

TheMaster said:


> When a toilet is flushed you can hear the siphon being broken at the end of the flush. Its not broken by the vent. The sound your hearing is the siphon being broken by the toilet sucking air from the room the fixture installed in.
> 
> A toilet is suppose to have an automatic trap prime through a refill hose on the ballcock....BUT toto had a 1.6 design(maybe they still do) with a ballcock that didn't have a refill hose and didn't have mechanical means of re-priming the trap. It was approved because even without a refill the trap was re-primed by the residual water left over from the flush as it drained from the rim of the fixture.
> 
> I suppose the code made an exception and they should have.....totos design didn't rely on mechanical means of re-primng the trap but rather on good design.


They still do, it's called the Dalton. Installed lots of them for smaller bathrooms, or powder rooms, cuz they only stick out 26" to front of bowl, & you can buy them in comfort height, with round front. I think the Promenade is now also available, & has the G-max flush, Dalton does not have G-max flush.
Exactly like TM said, it holds the "exact" amount of water in a little reservoir, in top of bowl, just below flush valve, & when the toilet finishes flushing, the water in the reservoir drains back out, & fills the bowl perfectly, everytime, without wasting water like a normal fill tube does.
Only problem is when the fill valves need replacing, how many are going to install the proper fill valve? This toilet IMO flushes as good as the rest, at about half the cost. Has standard flapper too.


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## Protech (Sep 22, 2008)

While not up to code, you could rough an entire single house in 6" with only 1 VTR at any point in the system and it would all work fine. No bubbles, no siphonage, no backups. Trap arms would be sized standard. The entire system would be combination waste/vent and would work perfectly. Wouldn't be to code, but it would work just fine.


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## Don The Plumber (Feb 14, 2010)

Protech said:


> While not up to code, you could rough an entire single house in 6" with only 1 VTR at any point in the system and it would all work fine. No bubbles, no siphonage, no backups. Trap arms would be sized standard. The entire system would be combination waste/vent and would work perfectly. Wouldn't be to code, but it would work just fine.


I agree, & I'll bet even 4" would do it.:yes:


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## RealLivePlumber (Jun 22, 2008)

You would be ok with 3" and a 1" vtr.


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## Protech (Sep 22, 2008)

I dunno, that seems a bit small. I don't have any evidence to support that though.



RealLivePlumber said:


> You would be ok with 3" and a 1" vtr.


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## Cal (Jun 17, 2008)

RealLivePlumber said:


> You would be ok with 3" and a 1" vtr.


Bet that would whistle out the vent :whistling2::whistling2:


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## RealLivePlumber (Jun 22, 2008)

My 1960 house is 1 bath, with 3" copper stack to 4"c.i. to septic tank. 1) 3" vtr for bathroom. (kitchen is on other side of house, independent 2" drain with 1 1/2"vtr to septic tank)

I'll scamper up on the roof this week, (gotta clean the gutters anyway) and fernco on a bushing to 1", and see what happens.


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## jeffreyplumber (Dec 7, 2009)

*self venting*

Never heard of self venting. Maybey you are talking about internaly trapped. A toilet has a trap built in. tubs of course dont


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## Cal (Jun 17, 2008)

jeffreyplumber said:


> Never heard of self venting. Maybey you are talking about internaly trapped. A toilet has a trap built in. tubs of course dont



Uh ,,, yeah ,, i know that . It was just that the phrase has been kicked around here over the last years and just wanted clarification . Thx


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## njoy plumbing (May 19, 2009)

TheMaster said:


> Not to the open air I didn't. That entire bathroom is revented back to that one 3" stack thats also serving the toilet. The only vent that was open was 30-40 ' away. I believe it was acting like a combination waste and vent....in other words the pipe never filled up enough create a siphon and air could travel above the water....and I did have an open vent way down the line to equalize the pressures between the pipe and the open air. So you are right that I did have a vent but I dont think it broke the siphon.....I dont think the pipe ever filled up enough to siphon.[/quot
> Agreed. I remember many:whistling2: years ago in 1st year class, and instructer mentiones that as well. He reminded us that over time though you will lose some of the inside diametyr of your pipe to build up so that is why the code is adhered to specificlly. That is why you find some old homes with poor flushing w.c's or drains that slow drain.:yes:


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