Steps for diagnosing sewage smell?

[rschmitty]

Moved to a new home and we have an occasional sewage smell that we detect in non-bathroom rooms. There were 2 owners before us, and the 2nd owners finished the basement. No idea if it was DIY or professional.

Sometimes when we flush a toilet in the basement we will get a whiff of sewage smell in the basement office OR our kitchen OR our master bathroom/closet on the first floor. The office is below the master bedroom and sometimes you can smell it in both the master bath and the office.

So far I have not smelled the sewage in the actual basement bathrooms.

Is there anything a DIY person can do to figure out where the gas leak is? If not, are there any special tools I should be asking the plumber that he will use to diagnose this issue.

 

[Reach4]

I suspect it may be bad venting. However try the easy stuff first. Add water to any drains, including floor drains, that you use only occasionally. This is to fill the P-trap with water to provide the seal. This seems unlikely to be the problem due to where the smells appear, but worth checking.

I would think this would be tough to diagnose if the smell is not coming from an identifiable location.

 

[Sponsor]

 

[rschmitty]

Thanks Reach4, we have been keeping the basement items in use at least once a week. There are 2 sinks, 2 toilets, and 1 shower. Each saturday I will flush both then run water in sinks and shower for a few minutes. I assume it doesnt take much water to fill up the P trap?

Since I work in the basement office I will use 1 of the bathrooms (the one in question) frequently both sink and toilet daily. For the other bathroom, is once a week enough to keep a P trap filled?

Is there anything I can do to inspect the venting? Any special tools a plumber should have to do a thorough job of testing the vents? Some kind of pressure test?

 

[Reach4]

You did not mention floor drains or the laundry output.

I figure that a cup of water would be more than enough for most drains, and maybe a pint for a floor drain. Overdoing it does not hurt.

Sniffing the drains each time you detect the smell would be good. Maybe invite in a guest sniffer. Would this be child abuse?

I am not a plumber, but I would think a pressure gauge would be good. For low pressures, this is often called a manometer. You could make a cheap version yourself. Get some clear flex tubing, such as discarded oxygen tubing if you know somebody on oxygen. Snake that down a drain past the trap. Blow vigorously to remove any water from the tube. Then put the near end of the tube into a glass of water. Normally the water level in the tube should match the level outside of the tube. Pressure would push the water level down. A half inch of difference is a lot, and I would think a quarter inch might be significant for diagnosis. Then watch the level ,while somebody flushes the problem toilet. Try other drains too maybe. If you see the water level pushed down that would represent a temporary pressure.

This is just a simple idea, and I have not tested it out.