Sewage smell thru bathroom sinks

[Zanne]

heater, I'm glad you figured out the problem for some of the sinks and managed to get things resolved.

IFIXH20, thanks for the info explaining about it being the water in the P-trap and not the pipe length. Also, the vinegar thing sounds like a good idea for cleaning the overflow.

 

[heater963]

Hi Zanne,

The smell is back with a vengeance! All 3 sinks again. I covered the sink overflow with tape and the smell came out the sink drain instead. I sent compressed air up the 2" stack vent and checked the vents on the roof. All had air coming from them.

I think there is a design flaw in this plumbing system, as none of the vents appear to be clogged or blocked. I am going to have to locate a good plumber.

Thanks for all of your help on this. When i figure out what caused this I will post the answer and solution. (Hopefully, I don't have to pawn my computer to pay the plumber)

 

[Zanne]

Yikes. Sorry the things you tried to resolve it didn't work. I hope you get a good plumber for a decent price and can get things solved.

 

[heater963]

I think I figured it out...AGAIN. I went up to the roof and added a four foot extension to the two vent stacks the involved sinks use. The additional 4 feet to the stack cleared the high point of the roof in both applications. I came down and checked the sinks. After testing ALL of them several times, I can happily report that the smell is no longer coming up the overflow or drain of any of the involved sinks.

I think the fact the home is located in a fairly deep canyon caused this "venting problem." I do not think the UPC codes take "canyons" into account when they publish their codes. It seems to be the answer to this particular problem.

Thank you everybody for helping me. I know I learned something here.

 

[Zanne]

I think I figured it out...AGAIN. I went up to the roof and added a four foot extension to the two vent stacks the involved sinks use. The additional 4 feet to the stack cleared the high point of the roof in both applications. I came down and checked the sinks. After testing ALL of them several times, I can happily report that the smell is no longer coming up the overflow or drain of any of the involved sinks.

I think the fact the home is located in a fairly deep canyon caused this "venting problem." I do not think the UPC codes take "canyons" into account when they publish their codes. It seems to be the answer to this particular problem.

Thank you everybody for helping me. I know I learned something here.

That's interesting. I didn't realize the height of the vent stack could have that effect.

I really hope that it has cleared up now.

 

[heater963]

Hi Zanne,

It is definitely related to the stack height. I think it really has a lot to do with the fact the house is located in a fairly deep canyon and therefore has less wind to create a pressure differential and get the gas flowing out of the stack.

I have been watching and testing when there is a breeze versus when it is still in the canyon. When there is a breeze, there is no smell of sewer gas from any of the sinks. When it is calm, there is still a slight sewer gas smell, but hardly as pronounced as it was prior to increasing the stack length.

It seems to be somewhat of a unique problem and the recommendation that I add even more length to the involved vent stacks came from a fella named Stuart Meade, who has a business in Indiana, designing and installing septic systems.

I had added a 2 foot length to each stack initially and he recommended I add even more length and re-check. It made a world of difference and it makes sense in that the extra length would potentially get more airflow across the stack, thereby creating the pressure differential needed to vent properly. So, i now have two vent stacks that are about 4 and a half feet from the roof. The worst sink vent stack now clears the highest point of the roof, so I know that alone allows it to get more airflow across the stack.

My concern now is the stacks becoming "sails" in a Winter storm.

Thanks for all your help. I am elated I did not have to call in a Plumber, as I doubt the diagnosis and "fix" would have been as easy on the old wallet.

Thanks again.

 

[Zanne]

I'm no expert on aerodynamics, but with the way vent stacks are shaped, I don't know if winter storms would affect them.

I'm glad that extending the vent stacks worked to resolve the problem and that you didn't have to hire a plumber for it.

Thanks for updating us on the progress. Hope things are finally cleared up for you now.

Cheers!