Apartment toilet and sink drain issues

[makersmonk]

Problems:

All sinks in the two story apartment stink underneath and from the drain

Water levels in one toilet lowers over time (within one day)
1. Floor is dry
2. seal was replaced
3. flap was replaced
4. this bathroom stinks reallly badly
5. vent on roof was checked
6. It bubbles when I flush it
7. all other functions seem to work normally
8. a simple auger was used with no success
9. flushing seems to cause the bubbling to go away after many flushes (bubbles may just be reduced in size)

Ventilation pipes underneath every sink were capped to try to prevent the smell and nothing changed. They then had holes drilled into the ventilation caps but kept the sink side capped. Bleach was also poured down the drain and only provided a very temporary effect.

*im not sure that the toilet problem existed before or after the capping of the vent pipes occured*

Any ideas? I am completely fed up with my apartment manager, he keeps sending simple day laborers to do plumbing work that they really have no clue about.

 

[Terry]

How about some pictures, 800 pixels or less.

By ventilation cap, do you mean AAV's Air Admittance Valve
If so, those can't be modified without ruining them.

 

[Sponsor]

 

[makersmonk]

just noticed that the vent pipes dont have anywhere to go to normally. My apartment building is a total of three stories, my actual apartment is two stories.

Upstairs bathroom sink (double sinks, both look the same) and looks the same for guest bath sink upstairs as well.

 

[Terry]

Those were glued on caps that did nothing.
Now someone has drilled them out, which allows the traps to be vented, but it now allows sewer gas to come into your home.

They should have been something like this.

https://ipscorp.com/plumbing/brands/studor/

 

[Gary Swart]

Now you know why some folks refer to vents as "stink pipes". Air Admittance Valves are not a popular choice among the professional ranks, but that what you have. The do work, but since they are a mechanical device, they are subject to failure. For that reason, if they are used, they must be accessible for replacement. As you can see in Terry's photo, they have male screws on the bottom end. This screws into a threaded female adapter that is solvent welded to the PVC pipe. I would extend the PVC pipe as high as possible and still be able to screw the AAV in/out.

 

[Jadnashua]

If the pipes aren't vented internal to the wall, then those stubouts need an AAV installed on each one.

One source of smell in any sink with an overflow is that the overflow gets some crud in it. If bleach helped in the main drain, try some also down the overflow.