Constant Sewage Smell in Commercial Building

[plumbingreceptionist]

Hi! I am an Office Manager for a plumbing company, not a plumber by any shape or form but I take all the calls and deal with the upset customers - LOL.

Anyway 2 of our best guys are on a commercial job for a Bank that has a constant horrible sewer smell. This is our third day on the job and we still have no found the source of this dang odor. All plumbing fixtures are working fine there are no clogs and all p-traps are wet. The smell is apparent everywhere but could possibly be worse in the janitorial closet. There is a cleanout in the janitorial closet where our guys ran a snake and hydrojetter. This helped alleviate the smell a little bit but when bank employees returned the next day the horrible smell was just as bad as it has been. Then we did a camera inspection for an hour and a half through that same cleanout and there were no huge red flags, there were some visible cracks in the pipes but this is normal for the guys to see - on previous jobs they have seen cracks on camera and exposed pipe only to find no leaks - nothing of a red flag situation or reason to believe that there is definitely leak in the pipe, not to say there ISN'T a leak in the sewer pipes. Anyway, today our guys are doing a camera inspection of the vents to see the condition, see if there are any clogs or damage.

Anyone have any experience with a situation like this? If so what was the resolution?

I keep researching and debating about persuading the owner to buy a smoke blower but since I have been working here we have never needed one until now. This is the first real pickle our guys have encountered, usually they knock-out any and all plumbing jobs.

Also something they did notice:

In front of the building there are 3 cleanouts that are holding water and when they tried to clear those lines there is a blocked that none of our snakes or even commercial snakes can penetrate. Our customer requested we hydrojet the line and all that did was cause water to push out from the cleanout next to it.

I am all ears for suggestions.

If it helps I can upload the camera inspection videos.

 

[Twowaxhack]

Mix 2oz of pure peppermint oil per gallon of warm water and pour down each roof penetration while a few people are in the building that haven’t been exposed to the peppermint mixture.

Turn off all hvac and fans for the first 10-20 minutes. If no peppermint smell is detected in the building then turn on all regular hvac equipment and ventilation fans. Check for smell.

This will at the very least prove or disprove the smell is actually sewer gas.

 

[Geofd]

Check air handler rooms,the traps will evaporate because of the air movement, is the a commercial kitchen???

 

[plumbingreceptionist]

Check air handler rooms,the traps will evaporate because of the air movement, is the a commercial kitchen???

There is no kitchen, the commercial building is a bank

 

[amj105]

Crack on the top of vent pipe in plenum (I hated that one) been there.

 

[RickFlorida]

Sounds to me like not being able to blow out all 3 cleanouts outside is related. I think a leak detector company or anyone with good pipe cameras need to inspect where the blockage is. The blockage may be well outside the building but his holding gases inside I suppose.