Confirm lack of proper venting on 1950's home

[erk1313]

Just purchased a 1950s home in NH and looking to replace the basement washer. Before I start, wanted to confirm the existing venting is acceptable.

I have left out the plumbing for the washer and utility sink for later (right now it is being piped up without a standpipe or P-trap). I can add details like diameter, lengths, types of fixture if needed, but wanted to answer some basic venting questions first to see if I need to dive into this.

1) First off, I am confused whether only the top fixture (toilet) can be stack vented, or if the entire bathroom group can be treated as a wet vent since it's off a large horizontal drain (likely not filled completely and able to pass gas). The kitchen sink2 cannot be wet-vented as part of the bathroom group, correct?

2) Does the toilet need to be downstream of all other fixtures on that branch draining to the main vent?

3) Do the S-traps violate the ability to stack vent the sinks?

Diagram of 1st floor fixtures draining below to the basement.


Thanks in advance. If this is not properly vented, then I can come up with some ideas for others to critique, along with my plan for plumbing the washer, sink, and pump.

 

[WJcandee]

Here's some helpful reading:

Plumbing-and-Trenching-for-Homeowners---2018 (klickitatcounty.org)

Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

 

[Sponsor]

 

[erk1313]

Thank you for the guides. They are quite helpful, but I wasn't able to answer the questions I had about the existing venting.

 

[hj]

The way you have it drawn, (and the pictures), show that this was done by a "hack" who had no idea how to install plumbing and it could not have passed inspection unless he gave the inspector a 'gratuity". Essentially, there is NO "existing venting".. It is so bad, that the only way to correct it will probably be to tear it out and start over.

 

[erk1313]

Ug. I was afraid of that... Let me mull it over a bit and post a proposed solution. The good news is that it is a single story ranch with clear shots to the attic. I believe the 1970s addition in the crawl space is plumbed correctly, but will now take a closer look. Are there actions I can take against the previous owner or home inspector for missing this?

 

[erk1313]

For my sake in understanding, could I request specific answers to the following:
1) Can a bathroom group be treated as a wet vent if it's off a large horizontal drain, or can only the fixture that first drains to the stack be stack-vented?

2) Do the S-traps violate the ability to stack vent the sinks (all other factors ignored)?

 

[hj]

quote; ) Can a bathroom group be treated as a wet vent if it's off a large horizontal drain

That has absolutely NOTHING to do with whether it is a wet vent or not. HOW the piping is arranged determines that, and nothing you have there qualifies as a "wet vent". By definition, an "S" trap CANNOT be vented, (if it could, it would NOT be an "S" trap). After 65 years, there is no way anyone could be held liable for this mess.

 

[erk1313]

Thank you for the reply. I was hoping that I missed something that would make everything all right, though my common sense was telling me that you can't vent a whole group of fixtures from the main stack like this. Could you help me grasp how I am interpreting the following article wrong? Is the red line actually a separate vent line in addition to the black drain line? I am not trying to justify the wrongness of my existing plumbing, just trying to sort out the rules to follow.

Wet Venting (http://bsj.iccsafe.org/june/inside_icc/pmg_plumbvents_part_3.html)
Wet venting is limited to any combination of fixtures within two bathroom groups.
The dry vent, the vent that continues upward from the wet vent to the point of termination of connection to another vent, shall be either an individual vent or a common vent to the lavatory, bidet, shower or bathtub, but not the water closet. In horizontal applications, the dry vent needs to be installed downstream of the first fixture drain or as an individual vent or common vent upstream of the last fixture drain.
------------
I will do some thinking tonight and propose a solution. Thank you for your help!

 

[WJcandee]

Okay, before you do too much pondering, understand that if you're within the Lebanon, NH city limits, it appears to follow (from its website) the 2000 version of the IPC. The article you cite to is all about how shady, cheap developers can use the changes in the 2009 version of the IPC to do all sorts of crappy venting that would be barred by the UPC and (to a significantly-lesser extent) previous versions if the IPC. Venting is the big deal in the IPC. Its proponents claim that "science" has allowed them to determine that all sorts of previously-considered-to-be-half-assed venting approaches are in fact just fine. "Adequate" is the word used in your article. Nobody advocating the venting approaches used in later versions of the IPC ever seems to call them "good" or "great". In the diagram you have, the builder is going to use a single 1.5" sink vent (which vents the traps of dual sinks) upstream of two toilets and a shower as a means to vent all those fixtures. Assuming the toilets are modern ones, I'm pretty confident that flushing both toilets at the same time stands a decent chance of siphoning that shower trap, particularly if the sinks are draining, although the IRC folks say that that layout is "adequate".

One important reason to install proper venting is to prevent trap siphoning and the resulting inflow of sewer gas to the premises. Follow the UPC, and those traps are never going to siphon. Shady, cheap developers want to cut down on plumbing costs and do the absolute minimum, so they love, love, love the IPC, because they are going to be long gone by the time the homeowner recognizes that they can't actually USE all their fixtures at the same time, the way a family of four (or my neighbors growing up -- a family of six kids and two parents sharing two bathrooms) might do every morning. But, hey, I'm biased towards doing things right so they work well under significant use, even if it costs a little more. And sounds like you are too.

Here's a link to the 2000 version of the IPC regarding vents:

Compare how a single bathroom is vented in the Klickitat County handout. Every fixture has its own vent. Klickitat County follows the UPC.
Plumbing-and-Trenching-for-Homeowners---2018 (klickitatcounty.org)

 

[hj]

Your drawing is incorrect, (and does not appear to be the same as your previous drawings or pictures). The "wet vent" STOPS when it connects to the first toilet, period. It has NOTHING to do with the second toilet or shower.

 

[erk1313]

Sorry for the confusion HJ. The last drawing is from an article on wet venting, not my existing plumbing. I believe the article is arguing that all of the fixtures along the red line are wet vented properly from the first lav. Thanks to wjcandee for scrutinizing the article to help me understand why some sources were very lenient to wet venting while others were not.

It is obviously going to take me some time to figure out what to do about this mess. From talking to my realtor and plumbing supply house, it seems like this is pretty common up here. What a shame! They say I should just throw on a few AAVs. I think I will first try to rectify the laundry drain that has no standppipe, trap, or vent, so my house can be functional, then figure out a plan to tackle the plumbing large scale. Thank you for your help.

 

[erk1313]

Here is a proposed layout for fixing the laundry drain. Adds a utility sink and pump (Liberty 404L (2" pipe) or 405). New vent connects to the stack vent in the attic.

 

[Cacher_Chick]

Lose the S-traps on the sinks. Venting sink 1 will properly wet vent the water closet if your diagram is true to form.

 

[hj]

The toilet is already properly vented. It is everything else that is the problem.

 

[erk1313]

Took awhile to figure out how to keep the plumbing below the utility sink. Orange is vent, blue is drain, green is discharge. Vent goes through attic and ties into main stack. Discharge from Liberty 404L goes through union/check valve (not modeled correctly) to above the main 3" drain. Any thoughts on what I missed or ways to make this cleaner? Do I need more cleanouts?

Is it okay to use a swing check valve without a spring?

 

[Cacher_Chick]

The vent and the outlet of the pump are on the top of the unit. The inlet is on the side.

 

[erk1313]

I appreciate you taking a look at my pipe routing, C_C. The owner manual says the inlet and vent ports are interchangeable. But do you think that it would be a problem? Also makes me wonder if I can lose the separate vent to the sink, since it dumps right into the pump and the pump is vented.
Manual: INLET: The pump has two ports: one on the top the other on the side, either can be used as a vent or inlet.

 

[Cacher_Chick]

I have never considered swapping them, as I would always want the vent to be vertical. Given the distance from trap to vented basin, there is not reason to vent the sink seperately.

 

[erk1313]

Good! So one extra vent pipe down; that will help clean this up. I will look at swapping the inlet and vent so the vent is on top. That makes more sense to me too. Thank you.

On second thought, looking at the pump, the vent and inlet and so close to one another entering the pump that it shouldn't make a difference. Just wanted to add that in case someone else is in a bind and needs to switch configurations.

 

[techi]

Okay, before you do too much pondering, understand that if you're within the Lebanon, NH city limits, it appears to follow (from its website) the 2000 version of the IPC. The article you cite to is all about how shady, cheap developers can use the changes in the 2009 version of the IPC to do all sorts of crappy venting that would be barred by the UPC and (to a significantly-lesser extent) previous versions if the IPC. Venting is the big deal in the IPC. Its proponents claim that "science" has allowed them to determine that all sorts of previously-considered-to-be-half-assed venting approaches are in fact just fine. "Adequate" is the word used in your article. Nobody advocating the venting approaches used in later versions of the IPC ever seems to call them "good" or "great". In the diagram you have, the builder is going to use a single 1.5" sink vent (which vents the traps of dual sinks) upstream of two toilets and a shower as a means to vent all those fixtures. Assuming the toilets are modern ones, I'm pretty confident that flushing both toilets at the same time stands a decent chance of siphoning that shower trap, particularly if the sinks are draining, although the IRC folks say that that layout is "adequate".

One important reason to install proper venting is to prevent trap siphoning and the resulting inflow of sewer gas to the premises. Follow the UPC, and those traps are never going to siphon. Shady, cheap developers want to cut down on plumbing costs and do the absolute minimum, so they love, love, love the IPC, because they are going to be long gone by the time the homeowner recognizes that they can't actually USE all their fixtures at the same time, the way a family of four (or my neighbors growing up -- a family of six kids and two parents sharing two bathrooms) might do every morning. But, hey, I'm biased towards doing things right so they work well under significant use, even if it costs a little more. And sounds like you are too.

Compare how a single bathroom is vented in the Klickitat County handout. Every fixture has its own vent. Klickitat County follows the UPC.

WJCandee......Great point!....

I need to get this out there, because too many experienced people are retiring and dying that know.

I am a practicing plumber, international and domestic code writer and engineer. Please don't hold that against me. I do failure analysis for space, aircraft and now plumbing...lol....I keep getting called in to explain why and its no short answer...there is a technical reason for it all......no one has the time or patience to spend it explaining or analyzing each plumbing drain system.....so short answer is follow UPC code first and that gets you 97% of way.

The UPC has been around.....and was originally written conservatively with smart people adapting Military specs.........over the years, the cost cutting barons and would be experts have changed it without regard for general welfare of the public.. I always get people wanting to modify or BEND the code to their will to save cost and run away as fast and far as they can. ............... How could our country grow if we have to spend it unclogging toilets?.......

Here is why.....we design for 80% of the application and use margins of 1.5. Why?.....because writing code needs to encompass a variety of configurations, giving plumbers and inspectors the freedom to plumb without having to engineer design and analyze each drain system.......It keep cost down, following code allows plumbing to work better than 80% of the time. The Margins also help to the system working reliability and helps covers the other 20% . Yes it is true, if you follow code it does not GUARRANTEE you will not have problems,...but you are assured better than 97 percent of the time.

I have been told..."I have been a plumber for XX years and not doing it this way works" ( no vents, excessive no. turns, using incorrect fittings, ignoring proper use of sanitary tees, etc....) Job security and stick it to the poor bastard consumer

My response....if it works, then its because the margin is there in the system, or it will be a problem in next 6-12 months. Not because the plumber found something better.....

Margins also exist for variations such as old pipes that start building up with sediment and the clogging of vents...

VENTING is important! -
1. No venting, no problem...........Wrong! I would have to do complete dissertation of this.
2. Wet venting - can work, is allowed in some states. Why? Because chances are the margin allows it and if you have a single clogged vent, another vent in the house keeps you safe. Clogs in vents are from frost, corrosion in pipe or debris....like leaves etc.....This is why you have to more than one vent..and sizing/no. requirements.

Bottom line - follow code and work from there. Otherwise it will cost you and everyone time and money. 300buxs an hour.

UL engineer
Space engineer
Aircraft engineer
Reliability engineer
Licensed A &