Sewer Venting Question (possible issue)

[William Roberts]

I recently had a bathroom redone on my 1st floor and have noticed the toilet does not flush as well since the project was completed. It sometimes has no power to the flush, has no/low water in the bowl and/or has low water in the tank. I attached a rudimentary diagram of the sewer piping. I have a shower, laundry, toilet and sink all feeding into a 3 inch main. Each of those inlets has a p-trap associated with them. Downstream of all of those inlets is a 2 inch vent line that goes out to the roof. None of the individual inlets connect back to the vent, they all just connect to the main. The little research I have done indicates I need some additional venting for things to work correctly.

Looking to this forum to see if anyone can confirm my suspicions that I have inadequate venting. A bonus if I can get a suggestion/diagram of how to fix it. Thanks ahead of time to anyone who contributes.

 

[Geofd]

If the water in your tank is low it could be an adjustment on the fill valve, try that 1st,the water should be about an inch below the top of the plastic tube

 

[breplum]

I will say that your attempt for a horizontal wet vent system with an improperly located vent is the problem.

 

[MicEd69]

Every fixture has to be properly vented. You show a trap for the toilet in your drawing, so it is evident you are not well understanding plumbing and venting requirements. Pictures would help of everything you can see.

 

[William Roberts]

Every fixture has to be properly vented. You show a trap for the toilet in your drawing, so it is evident you are not well understanding plumbing and venting requirements. Pictures would help of everything you can see.

Thanks for the response. Just to clarify, the p-trap I illustrated for the toilet is just the built in trap that is part of the porcelain part of any toilet. There is not any PVC p-trap in the piping under the toilet.

 

[William Roberts]

If the water in your tank is low it could be an adjustment on the fill valve, try that 1st,the water should be about an inch below the top of the plastic tube

Thanks for the reply and idea. Unfortunately, I have already adjusted the fill valve so the water level is about an inch below the top of the plastic tube. There was no change in the behavior of the system and really not much adjustment needed (one or two turns).

 

[William Roberts]

I will say that your attempt for a horizontal wet vent system with an improperly located vent is the problem.

Thanks for the reply! A contractor did the work for the bathroom remodel as far as plumbing goes. I am just trying to fix any problems that person may have left behind for me (or reach out to them and have them fix it). Do you have any more details on what exactly is improper about the current design?

 

[GReynolds929]

Do you have any more details on what exactly is improper about the current design?

None of the traps and fixtures are vented based on what can be interpreted of your drawing. Look up isometric plumbing diagram and try something like that. It will help us better understand how everything is run.

 

[William Roberts]

I was able to climb down in the crawl space today and get an overview picture to help add clarity to the exact setup based on feedback. I tried to label the information to help explain what is going on. This area is cluttered with HVAC, wiring, water supply, radon AND sewer. So try to ignore anything I have not labeled. Hopefully this can help with the discussion. I also took close-up pictures of each area but not sure they add much value at this time. I can upload those if anyone wants to see something in more detail.

It's great to get confirmation that there is a likely venting issue. Now I just have to figure out how to get it fixed. Thanks again for all the help from the folks who have replied.

 

[William Roberts]

Every fixture has to be properly vented. You show a trap for the toilet in your drawing, so it is evident you are not well understanding plumbing and venting requirements. Pictures would help of everything you can see.

I posted pictures now.

 

[William Roberts]

None of the traps and fixtures are vented based on what can be interpreted of your drawing. Look up isometric plumbing diagram and try something like that. It will help us better understand how everything is run.

I posted pictures.

 

[MicEd69]

I'll start from the beginning of the drain line, a very good place to start. LOL. The shower is not vented per ANY code whatsoever. The laundry standpipe is not vented per ANY code whatsoever. The toilet is almost vented, except the existing vent looks to have an elbow that goes horizontal before it reaches at least 6" above the flood point of the toilet. While that is not the main reason that vent doesn't vent the shower or laundry, the horizontal run would also be another reason that vent is not acceptable for those two items. And if the sink isn't vented after the P- trap, it is an illegal S-trap.

As I said above, as the vent turns horizontal before reaching 6" above the fixture(s) it serves, it is against all codes. If the sink would drain into the vent line, that would appropriately vent the sink and wet vent the toilet at least.

 

[GReynolds929]

There is nothing correct about that drainage plumbing. Laundry trap needs to be above floor and have it own vent, shower is not vented and needs it's own vent it can't be wet vented due to the laundry tying in. Drain should be 2" from shower all the way to the toilet. Lav sink can wet vent toilet if drained through the vent pipe. Wrong fittings used. Santees are not allowed to be on their back like that, they are strictly for horizontal to vertical connections. The correct fitting is a combo.

 

[William Roberts]

Thanks for the reply! This is what I suspected I would hear. To clarify, do you mean a separate main vent stack out of the roof of the house for each or just a separate tie-in to the main vent? Sounding like I might need to hire an actual plumber.

There is nothing correct about that drainage plumbing. Laundry trap needs to be above floor and have it own vent, shower is not vented and needs it's own vent it can't be wet vented due to the laundry tying in. Drain should be 2" from shower all the way to the toilet. Lav sink can wet vent toilet if drained through the vent pipe. Wrong fittings used. Santees are not allowed to be on their back like that, they are strictly for horizontal to vertical connections. The correct fitting is a combo.

 

[GReynolds929]

Vents can be combined as long as you have the same aggregate venting area as the main drain exiting the house. IE: 3" sewer, you need the equivalent or more of 3" venting out the roof. If this is an add on there should already be enough venting through the roof.

 

[MicEd69]

Thanks for the reply! This is what I suspected I would hear. To clarify, do you mean a separate main vent stack out of the roof of the house for each or just a separate tie-in to the main vent? Sounding like I might need to hire an actual plumber.

Yes, you definitely need to hire a professional plumber. The person who installed that mess does not know anything about drains or vents. Wrong fitting choices, wrong vent layouts, wrong just about everything. There WILL be problems if you leave it like it is. Adding vents will NOT fix this mess.

 

[William Roberts]

Appreciate all the help and advice! Time to start looking for a reputable plumber in my area of Missouri. I want to get this fixed to code and working correctly to avoid any larger issues.