Drain vent
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My assumption is that the vent line is an actual dry vent, correct?
That line does not vent the shower per code because of the short section of the sewer line that has flow from a toilet between where the shower meets the sewer line and the vent. It would be better to add a connection to the vent line from the horizontal line from the shower P-trap.
Will it work as is? Probably, but it's not per code. However, you should see what your inspector says, he might say it is OK. You also need to have some cleanouts in the vent line so you can snake it in case of a blockage.
And don't worry about the backflow preventer unless the inspector says you need one. And if you do, just put one in each of the sewer lines that exits you house.
It's hard to provide good advice on something that is already a problem layout. I would have done things a lot differently, but to rework the entire layout isn't practical at this point. All you need to worry about is making the inspector happy.
That line does not vent the shower per code because of the short section of the sewer line that has flow from a toilet between where the shower meets the sewer line and the vent. It would be better to add a connection to the vent line from the horizontal line from the shower P-trap.
Will it work as is? Probably, but it's not per code. However, you should see what your inspector says, he might say it is OK. You also need to have some cleanouts in the vent line so you can snake it in case of a blockage.
And don't worry about the backflow preventer unless the inspector says you need one. And if you do, just put one in each of the sewer lines that exits you house.
It's hard to provide good advice on something that is already a problem layout. I would have done things a lot differently, but to rework the entire layout isn't practical at this point. All you need to worry about is making the inspector happy.
mrordinary
Member
1. At the entry point to that wye it is dry, so I believe this fits the definition?
2. Will it not meet code because the dry vent has to run vertically above the flood level rim?
In the case of the toilet does that mean the bowl?
In the case of the shower, that would be the drain.
In the case of the sink, is that the overflow?
Or is it the P trap?
Do vent lines typically have cleanouts?
Thank you.
2. Will it not meet code because the dry vent has to run vertically above the flood level rim?
In the case of the toilet does that mean the bowl?
In the case of the shower, that would be the drain.
In the case of the sink, is that the overflow?
Or is it the P trap?
Do vent lines typically have cleanouts?
Thank you.
mrordinary
Member
I live in NJ so I believe we are using NSPC plumbing code. If I am reading this correctly, it may fall into code with code: 12.6.2.2 Slope of Horizontal Vent?
Figure 12.6.2 - B
HORIZONTAL VENT PIPING BELOW THE FLOOD LEVEL RIM OF FIXTURES
12.6.2.1 Horizontal Vent Below Fixture Flood Level Rim
Where a vent pipe connects to a horizontal fixture drain branch, and conditions require a horizontal offset in the vent below the flood level rim of the fixture served, the vent shall be taken off so that the invert of the horizontal portion of the vent pipe is at or above the centerline of the horizontal sanitary drain pipe.
12.6.2.2 Slope of Horizontal Vent
The portion of the horizontal vent installed below the flood level rim, as permitted in Section 12.6.2.1, shall be installed with the slope required to drain by gravity to the drainage system. See Figure 12.6.2-B
VENT PIPE CONNECTIONS TO HORIZONTAL DRAINS
https://up.codes/viewer/new_jersey/nj-plumbing-code-2018/chapter/12/vents-and-venting#12..6.2.1
From:
Figure 12.6.2 - B
HORIZONTAL VENT PIPING BELOW THE FLOOD LEVEL RIM OF FIXTURES
12.6.2.1 Horizontal Vent Below Fixture Flood Level Rim
Where a vent pipe connects to a horizontal fixture drain branch, and conditions require a horizontal offset in the vent below the flood level rim of the fixture served, the vent shall be taken off so that the invert of the horizontal portion of the vent pipe is at or above the centerline of the horizontal sanitary drain pipe.
12.6.2.2 Slope of Horizontal Vent
The portion of the horizontal vent installed below the flood level rim, as permitted in Section 12.6.2.1, shall be installed with the slope required to drain by gravity to the drainage system. See Figure 12.6.2-B
VENT PIPE CONNECTIONS TO HORIZONTAL DRAINS
https://up.codes/viewer/new_jersey/nj-plumbing-code-2018/chapter/12/vents-and-venting#12..6.2.1
From:
1. At the entry point to that wye it is dry, so I believe this fits the definition?
So, there is nothing flowing through the line labeled vent upstream from the connection to the sewer line. That is a dry vent then.
2. Will it not meet code because the dry vent has to run vertically above the flood level rim?
I may have left you with the wrong impression with my responses, and I did say things would not be per code when actually they are allowed, they are just not best practice IMHO. I would have done things differently to avoid any horizontal vent lines. Like run the shower line under a wall so that I could vent it vertically up that wall. So, let me respond to these items below.
In the case of the toilet does that mean the bowl?
If the toilet vent is maintained vertical or not more than 45 degrees off vertical until it reaches 6" above the bowl height, that is best. But you can run a horizontal vent line sloped 1/4" per foot towards the sewer and go vertical as soon as possible. A cleanout for that vent line needs to be provided.
In the case of the shower, that would be the drain.
The shower is the same as the toilet, except the height restriction is 6" above the shower entrance threshold. And if it has to run horizoltal, the slope and cleanout requirements apply to it as well.
In the case of the sink, is that the overflow?
For sinks, it usually very easy to avoid any horizontal vent lines until the level of the vent line reaches 6" above the flood plain of the sink, that being the top of the sink, not the overflow hole on the sink.
Or is it the P trap?
The top of the sink.
Do vent lines typically have cleanouts?
Horizontal dry vent lines require a cleanout.
Using your layout, let's assume you have a blockage at the wye connection of your two large sewer lines downstream from your new vent connection. What is going to happen? Water and sewage will fill up the shower drain line and will back up into the dry vent line until the level in the lines raises to the level of the shower, and those wastes will come up into the shower base. As the dry vent has no water flow from upstream, as the blockage starts to be cleared, the velocity in the dry vent line will be relatively slow. As such, any solids that have accumulated there will remain until they are mechanically or hydraulically cleaned or flushed out. Hence the requirement for a cleanout in that vent line.
And as I indicated in an earlier post response, "That line (the vent line) does not vent the shower per code because of the short section of the sewer line that has flow from a toilet between where the shower meets the sewer line and the vent. It would be better to add a connection to the vent line from the horizontal line from the shower P-trap." You cannot wet vent anything in a line that has flow from a toilet. I know it's only a few inches, but the code is the code.
And as I also said in an earlier post response, "It's hard to provide good advice on something that is already a problem layout. I would have done things a lot differently, but to rework the entire layout isn't practical at this point." That is why it is important to think through the sewer routing and venting requirements. Running sewer lines under a wall is a great way to allow proper venting without having to worry about horizontal lines getting plugged during a sewer problem.
And mrordinary, you provided some good descriptions and information.
So, there is nothing flowing through the line labeled vent upstream from the connection to the sewer line. That is a dry vent then.
2. Will it not meet code because the dry vent has to run vertically above the flood level rim?
I may have left you with the wrong impression with my responses, and I did say things would not be per code when actually they are allowed, they are just not best practice IMHO. I would have done things differently to avoid any horizontal vent lines. Like run the shower line under a wall so that I could vent it vertically up that wall. So, let me respond to these items below.
In the case of the toilet does that mean the bowl?
If the toilet vent is maintained vertical or not more than 45 degrees off vertical until it reaches 6" above the bowl height, that is best. But you can run a horizontal vent line sloped 1/4" per foot towards the sewer and go vertical as soon as possible. A cleanout for that vent line needs to be provided.
In the case of the shower, that would be the drain.
The shower is the same as the toilet, except the height restriction is 6" above the shower entrance threshold. And if it has to run horizoltal, the slope and cleanout requirements apply to it as well.
In the case of the sink, is that the overflow?
For sinks, it usually very easy to avoid any horizontal vent lines until the level of the vent line reaches 6" above the flood plain of the sink, that being the top of the sink, not the overflow hole on the sink.
Or is it the P trap?
The top of the sink.
Do vent lines typically have cleanouts?
Horizontal dry vent lines require a cleanout.
Using your layout, let's assume you have a blockage at the wye connection of your two large sewer lines downstream from your new vent connection. What is going to happen? Water and sewage will fill up the shower drain line and will back up into the dry vent line until the level in the lines raises to the level of the shower, and those wastes will come up into the shower base. As the dry vent has no water flow from upstream, as the blockage starts to be cleared, the velocity in the dry vent line will be relatively slow. As such, any solids that have accumulated there will remain until they are mechanically or hydraulically cleaned or flushed out. Hence the requirement for a cleanout in that vent line.
And as I indicated in an earlier post response, "That line (the vent line) does not vent the shower per code because of the short section of the sewer line that has flow from a toilet between where the shower meets the sewer line and the vent. It would be better to add a connection to the vent line from the horizontal line from the shower P-trap." You cannot wet vent anything in a line that has flow from a toilet. I know it's only a few inches, but the code is the code.
And as I also said in an earlier post response, "It's hard to provide good advice on something that is already a problem layout. I would have done things a lot differently, but to rework the entire layout isn't practical at this point." That is why it is important to think through the sewer routing and venting requirements. Running sewer lines under a wall is a great way to allow proper venting without having to worry about horizontal lines getting plugged during a sewer problem.
And mrordinary, you provided some good descriptions and information.
mrordinary
Member
MicEd69,
Thank you so much for your help.
Unfortunately this is where the bathroom was in the 1929 home. The bathroom was apparently never vented at all or correctly. We replaced 4 inch cast iron with 3 inch pvc.
Yes, none of this project is ideal.
In the edited picture I have done the following:
A. Raised the shower higher so that a sewage backup won't get into that line. I tried to show a 45 wye from the center line attaching.
B. I moved the initial location of the dry vent to closer to the toilet.
Questions:
1. Is there any code that says you can't dry vent horizontal 15 ft and then go vertical to the roof as long as you have the right pitch? (I think you just said it is not best practice)
2. In this layout you will see a red coloring to represent the 2 inch vent intersecting with the horizontal line from the shower p trap and to vent the toilet. Is that an acceptable way to vent both?
Or do I need two separate parallel vent lines that go horizontal and then vertical?
3. Do you know what code the plumber is violating with not having a direct horizontal vent connection to the shower? I want to bring it to his attention.
4. Should the vent for the toilet be downstream like I put it or upstream?
Thank for helping this make more sense.
Thank you so much for your help.
Unfortunately this is where the bathroom was in the 1929 home. The bathroom was apparently never vented at all or correctly. We replaced 4 inch cast iron with 3 inch pvc.
Yes, none of this project is ideal.
In the edited picture I have done the following:
A. Raised the shower higher so that a sewage backup won't get into that line. I tried to show a 45 wye from the center line attaching.
B. I moved the initial location of the dry vent to closer to the toilet.
Questions:
1. Is there any code that says you can't dry vent horizontal 15 ft and then go vertical to the roof as long as you have the right pitch? (I think you just said it is not best practice)
2. In this layout you will see a red coloring to represent the 2 inch vent intersecting with the horizontal line from the shower p trap and to vent the toilet. Is that an acceptable way to vent both?
Or do I need two separate parallel vent lines that go horizontal and then vertical?
3. Do you know what code the plumber is violating with not having a direct horizontal vent connection to the shower? I want to bring it to his attention.
4. Should the vent for the toilet be downstream like I put it or upstream?
Thank for helping this make more sense.
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Last edited:
mrordinary
Member
I think I may have answered Question 2 (the connection with the shower p trap horizontal line)
It looks like we will need to have a separate 2 inch run for the toilet and the shower if I am reading this correctly:
We could tie them together when we get above the flood rim level of the toilet?
It looks like we will need to have a separate 2 inch run for the toilet and the shower if I am reading this correctly:
We could tie them together when we get above the flood rim level of the toilet?
12.6.3 Vent Connection Height Above Fixtures
Connections between any horizontal vent pipe, including individual vents, branch vents, relief vents, circuit vents or loop vents, and a vent stack or stack vent shall be made at least 6 inches above the flood level rim of the highest fixture on the floor level.First, let me comment on 12.6.3 that you cited. "Connections between any horizontal vent pipe, .... and a vent stack .... shall be made at least 6 inches above the flood level rim of the highest fixture on the floor level." So, this means that a horizontal vent pipe has to turn up and go vertical to a point 6" above the flood rim of the highest fixture that is being vented before it is connected to a vent stack. It does not mean that separate vents are required for each fixture.
But I still think I wasn't understanding your entire system until now, and I apologize for not getting a better understanding your system sooner. Please let me know if this describes the horizontal line of your system that we are discussing.
If I stand at the wye where the two large sewer lines combine and look upstream at the branch in question, at the far end is a 2" vertical pipe for a sink drain. The line then turns horizontal towards me and increases in size to 3". A 3" toilet connection then enters the horizontal sewer with a 3"x3"x3" wye lying flat. A little closer to me a shower drain enters the sewer with a 3"x2"x3" reducing wye lying flat. And then a little closer to me yet a 2" vent is in the 3" line with a 3"x2"x3" reducing wye with the branch of the wye at about a 45-degree angle up. that vent then runs above and parallel to the sewer line away from me. Is this correct?
I'm not totally familiar with the New Jersey Plumbing Code, but 12.10.2 Individual Water Closets says:
a. An individual water closet may be wet vented by an adjacent lavatory.
b. The wet vent from the lavatory drain shall be not less than one pipe size larger than one-half the size of the drain from the water closet.
c. The maximum length of the water closet trap arm to its wet vent connection shall comply with Section 12.8.4, horizontally and vertically.
d. The dry vent from the wet vent at the lavatory connection shall be not less than one-half the size of the drain from the two fixtures.
And 12.8.4 says:
"For water closets, clinical sinks, and flushing-rim service sinks with integral traps, the distance between the outlet of the fixture and its vent connection shall not exceed three (3) feet vertically and nine (9) feet horizontally."
So, the toilet appears to be properly wet vented by the 2" sink drain line and its dry vent off the sink P-trap arm. That dry vent should be maintained at 2" through the roof or its connection to the main vent stack. So, it appears that the only issue you have is that the shower P-trap needs to be vented properly. That can be accomplished by removing the 2" vent from the 3" sewer line and attaching it to the 2" shower drain at least 4" from the P-trap weir and the 3" sewer connection. That connection can be done with a Sanitary Tee on its back at a 45-degree angle up and fittings to connect it to the 2" horizontal vent pipe. I would run that vent pipe vertically at the far end until it is 6" above the top of the sink before tying it into a vent stack or run it separately through the roof.
And 12.6.2.3 Cleanouts says:
Cleanouts shall be provided in the vent piping so that any blockages in the vent piping below the flood level rim of the fixture served can be cleared into the drainage system.
Sorry for all the confusion in these answers. But I hope this provides you with the needed information without too much rework.
But I still think I wasn't understanding your entire system until now, and I apologize for not getting a better understanding your system sooner. Please let me know if this describes the horizontal line of your system that we are discussing.
If I stand at the wye where the two large sewer lines combine and look upstream at the branch in question, at the far end is a 2" vertical pipe for a sink drain. The line then turns horizontal towards me and increases in size to 3". A 3" toilet connection then enters the horizontal sewer with a 3"x3"x3" wye lying flat. A little closer to me a shower drain enters the sewer with a 3"x2"x3" reducing wye lying flat. And then a little closer to me yet a 2" vent is in the 3" line with a 3"x2"x3" reducing wye with the branch of the wye at about a 45-degree angle up. that vent then runs above and parallel to the sewer line away from me. Is this correct?
I'm not totally familiar with the New Jersey Plumbing Code, but 12.10.2 Individual Water Closets says:
a. An individual water closet may be wet vented by an adjacent lavatory.
b. The wet vent from the lavatory drain shall be not less than one pipe size larger than one-half the size of the drain from the water closet.
c. The maximum length of the water closet trap arm to its wet vent connection shall comply with Section 12.8.4, horizontally and vertically.
d. The dry vent from the wet vent at the lavatory connection shall be not less than one-half the size of the drain from the two fixtures.
And 12.8.4 says:
"For water closets, clinical sinks, and flushing-rim service sinks with integral traps, the distance between the outlet of the fixture and its vent connection shall not exceed three (3) feet vertically and nine (9) feet horizontally."
So, the toilet appears to be properly wet vented by the 2" sink drain line and its dry vent off the sink P-trap arm. That dry vent should be maintained at 2" through the roof or its connection to the main vent stack. So, it appears that the only issue you have is that the shower P-trap needs to be vented properly. That can be accomplished by removing the 2" vent from the 3" sewer line and attaching it to the 2" shower drain at least 4" from the P-trap weir and the 3" sewer connection. That connection can be done with a Sanitary Tee on its back at a 45-degree angle up and fittings to connect it to the 2" horizontal vent pipe. I would run that vent pipe vertically at the far end until it is 6" above the top of the sink before tying it into a vent stack or run it separately through the roof.
And 12.6.2.3 Cleanouts says:
Cleanouts shall be provided in the vent piping so that any blockages in the vent piping below the flood level rim of the fixture served can be cleared into the drainage system.
Sorry for all the confusion in these answers. But I hope this provides you with the needed information without too much rework.
mrordinary
Member
Any confusion is probably my fault.
Please see the picture called "Outline of sewer and vent" and "stack at wall". I believe this is the view you were describing, but I think you may have described the sink incorrectly. The sink goes directly into the 3" sewer line; according to the plumber it needs an AAV.
So to be clear, there is a 2" vent line that comes from the roof, to the basement, and then goes horizontal to the basement bathroom and attaches to the 3" sewer line. At the wall there is also a 3" sewer stack from the 1st floor bathroom that then goes horizontal under the slab. The basement sink is directly connected, the toilet then branches into it and finally the shower does. Currently the vent attaches to the 3" sewer right past the shower connection to the 3".
From all your feedback, I created the picture "Proposed change" to make the changes I believe you wanted. In the "Proposed change" I moved the vent to connect right after the toilet. AND then I branched the vent to the P-trap arm of the shower so it is vented (originally you said it was not vented)
I am not sure if I can branch the vent line to the p-trap shower arm due to 12.6.3 "a horizontal vent pipe has to turn up and go vertical to a point 6" above the flood rim of the highest fixture that is being vented before it is connected to a vent stack."
If I am right, the vent stack is at the wall. So the only time we get above the flood rim is 15 ft away. So I read that 12.6.3 meant that I can't branch the vent for both the shower and toilet since it never cleared the flood rim of either fixture. This is why I stated that it seems like I can't branch the 2" vent line for the toilet and the shower. I figured I need to run another 2" line to vent the shower and then put a "wye" at the wall when I am above the flood rim. And then I would need to add a cleanout for the vent.
Let me know if that makes any sense. I am very confused.
Please see the picture called "Outline of sewer and vent" and "stack at wall". I believe this is the view you were describing, but I think you may have described the sink incorrectly. The sink goes directly into the 3" sewer line; according to the plumber it needs an AAV.
So to be clear, there is a 2" vent line that comes from the roof, to the basement, and then goes horizontal to the basement bathroom and attaches to the 3" sewer line. At the wall there is also a 3" sewer stack from the 1st floor bathroom that then goes horizontal under the slab. The basement sink is directly connected, the toilet then branches into it and finally the shower does. Currently the vent attaches to the 3" sewer right past the shower connection to the 3".
From all your feedback, I created the picture "Proposed change" to make the changes I believe you wanted. In the "Proposed change" I moved the vent to connect right after the toilet. AND then I branched the vent to the P-trap arm of the shower so it is vented (originally you said it was not vented)
I am not sure if I can branch the vent line to the p-trap shower arm due to 12.6.3 "a horizontal vent pipe has to turn up and go vertical to a point 6" above the flood rim of the highest fixture that is being vented before it is connected to a vent stack."
If I am right, the vent stack is at the wall. So the only time we get above the flood rim is 15 ft away. So I read that 12.6.3 meant that I can't branch the vent for both the shower and toilet since it never cleared the flood rim of either fixture. This is why I stated that it seems like I can't branch the 2" vent line for the toilet and the shower. I figured I need to run another 2" line to vent the shower and then put a "wye" at the wall when I am above the flood rim. And then I would need to add a cleanout for the vent.
Let me know if that makes any sense. I am very confused.
Attachments
OK, if you can vent the sink to the roof instead of using an AAV, which appears easy to do as the proposed vent to the roof looks pretty close to the sink, then the toilet will be wet vented through the sink drain line and the dry vent for that sink. If you use an AAV for the sink, then that will not adequately vent the toilet, only the sink. Assuming you can do that, then the "new vent" needs to be disconnected from the 3" sewer line and only connected to the shower drain line before it connects to the 3" main. Then that vent can run following the same path as it is now, then up, and then connect to the sink vent at an elevation of at least 6" above the top of the sink. This is what I would do as it provide a good vent and I dislike mechanical devices for vents. They must be accessible, and they will fail in time.
Now theoretically, if you disconnect the vent line from the 3" main and connect it to the drain line from the shower before it hits the 3" main, I think the toilet will be properly wet vented through the short section of the shower drain between the vent and the 3" line, and then by the dry vent for the shower up to the roof. That way, you could use an AAV for the sink, if you wanted to.
But by venting the sink to the roof and combining the shower vent to the vent stack from the sink at least 6" above the top of the sink, you would provide dual paths for air to properly vent the toilet.
Now theoretically, if you disconnect the vent line from the 3" main and connect it to the drain line from the shower before it hits the 3" main, I think the toilet will be properly wet vented through the short section of the shower drain between the vent and the 3" line, and then by the dry vent for the shower up to the roof. That way, you could use an AAV for the sink, if you wanted to.
But by venting the sink to the roof and combining the shower vent to the vent stack from the sink at least 6" above the top of the sink, you would provide dual paths for air to properly vent the toilet.
mrordinary
Member
I was a little confused about wet and dry venting in your last response, but I am still confused. So I am going to backtrack to try to get on the same page with you.
I think your response was based on the purple shaded region (the dry vent going to the shower, and then connecting right after the toilet and then going to the wall and finally to the roof). Are you saying if I do that, then all 3 parts of the bathroom would be vented properly and an AAV is not necessary?
If so, where I am getting confused is when you said, "OK, if you can vent the sink to the roof instead of using an AAV, which appears easy to do as the proposed vent to the roof looks pretty close to the sink, then the toilet will be wet vented through the sink drain line and the dry vent for that sink."
Wouldn't the sink and the toilet be wet vented since the dry vent is not at or above the flood rim level.
mrordinary
Member
On another note I was looking at this:
12.10.3 Bathroom Groups
- Water closets and bathtubs or shower stalls in bathroom groups may be wet vented by the lavatories. (this seems to be what we are doing)
- The dry vent pipe from the lavatories shall be not less than one-half the size of the drain pipe for the group.
- The size of wet vent piping shall comply with the following: (1) be not less than one pipe size larger than the required drain pipe size for its upstream fixtures, and (2) be not less than one pipe size larger than one-half the size of the largest connected drain piping being wet vented downstream.
- The connection of fixture drains to horizontal wet vents shall be horizontal. Except for water closets, the upper portion of the wet vent opening shall not be below the weir of the fixture trap. (Does this mean that the vent line that connects to the shower arm should not be above the centerline?)
- The bathtubs or shower stalls may be connected to their water closet drain upstream from its wet vent connection. (We are in violation of this with the current setup right?)
- The maximum length of the fixture trap arms for lavatories, bathtubs, and shower stalls shall comply with Section 12.8.1.
- The maximum length of the water closet trap arms to their wet vent connection shall comply with Section 12.8.4, horizontally and vertically.
- Where fixtures are wet vented vertically, water closets shall connect to the wet vent at the same lowest elevation. Bathtubs or shower stalls shall connect to the wet vent at the same elevation as the water closets or higher.
"I think your response was based on the purple shaded region (the dry vent going to the shower, and then connecting right after the toilet and then going to the wall and finally to the roof). Are you saying if I do that, then all 3 parts of the bathroom would be vented properly and an AAV is not necessary?"
No. If you dry vent the sink, disconnect the existing vent from the 3" line, connect the existing vent to the shower drain, and connect that vent line to the dry vent from the sink at least 6" above the top of the sink, then all three parts of the bathroom will be vented.
"Wouldn't the sink and the toilet be wet vented since the dry vent is not at or above the flood rim level."
No. The sink is dry vented because you will install a vent through the roof instead of using an AAV. The toilet will be wet vented through the drain of the sink and the dry vent of the sink. The shower will be dry vented through its vent line and then connection to the dry vent of the sink at least 6" above the top of the sink.
"1. Water closets and bathtubs or shower stalls in bathroom groups may be wet vented by the lavatories. (this seems to be what we are doing)"
Yes.
"4. The connection of fixture drains to horizontal wet vents shall be horizontal. Except for water closets, the upper portion of the wet vent opening shall not be below the weir of the fixture trap. (Does this mean that the vent line that connects to the shower arm should not be above the centerline?)"
No. If you disconnect the vent from the 3" line and connect it to the shower drain, that vent becomes a dry vent. And as indicated in the referenced "12.6.2.2 Slope of Horizontal Vent" in an earlier post, that connection needs to be vertical or no more than 45 degrees off vertical. And just note that while you've indicated a wye connection for that vent, a Sanitary Tee on its back positioned vertically or rotated at no more than a 45-degree angle is acceptable for the shower dry vent connection.
"5. The bathtubs or shower stalls may be connected to their water closet drain upstream from its wet vent connection. (We are in violation of this with the current setup right?)"
No. Note the word "may". it does not say "shall be".
I just did a bathroom for my nephew in his basement. I dumped the toilet first, then shower, I dropped a dry vent with cleanout in between shower and vanity into the 4" main. I stubbed the vanity up 3" with a cleanout on the backside and then 2" up to sink and AAV off the top. All vents were accessible AAV's. The inspector was fine with it because all my fixtures were within limits from a vented line. I did not put individual vents to any of the fixtures and the vanity was the only wet vent. I think your best bet is to run that piping then call for inspection and see what he tells you. I did have to install a backwater valve as they are code in his city and I forgot to have him ask when he applied for the permit.
Best bet is a proper horizontal wet vent, running 3 inches. And 2 inches from the most upstream that becomes the wet vent......
Don't know where u at with the project but can speak more later if needed