I am detecting a faint odor of sewer gas in the bathrooms of my house. My wife believes it is stronger after leaving the lid of the toilet down, not that this is air-tight, but perhaps it allows a pocket of gas to accumulate? We are on a public sewer. What are the SDopers thoughts about these suggestions to self-diagnose (if not a city problem):
Note: Perhaps related, the half-bath toilet (virtually at ground level) will periodically have a non-productive flush without overflowing, but a second flush will usually clear it.
a) My vent stacks on the house may be partially blocked by some foreign material (dead bird, debris, etc.)
b) My vent stacks are too short. (Should I check the BOCA Code on this?)
c) The line out to the street may be partially blocked.
The wax ring around the toilet base may need replacing; however, the fact that the odor is present in ALL bathrooms makes me doubt that this is the issue.
The vent stack height would have been checked during house construction (assuming your house was constructed when BOCA was enforced), and I doubt that its length is an issue.
Check up in the attic and see if you can smell it up there. May be an obstructed vent stack.
Also make sure you dont have any dry traps in the house. Sometimes if a trap dries out you can get the gas smell in the house. Pour water down every drain that doesnt get regular use to fill the traps back up.
A trap is a goosenecked shaped bend in the pipe that prevents sewer gas from enering the house by assuring that water stays in the trap thus not allowing gas to pass.
I’ll second the call for checking no traps are dry. Sometimes one dry trap can really let a lot of unpleasantness inside, and it’s hard to pin down, from a smell standpoint.
I tend to favour a). With b) the smell would be most noticeable outside the house, and with c) you would notice just the nuggets, not the sewergas. If you lift the toilet out, remember to replace the wax seal with a new one, do not reuse the old seal. The ground level toilets’ reluctance to complete the flush may be caused by a too small a vent size, too long a distance to the stack or insufficient slope in your waste line.
A blocked vent stack won’t cause a smell in the house. The purpose of the vent stack is to allow air to flow freely both into and out of the waste pipe system, not to vent nasty smells. The distance that the vent stack protrudes above the roof is relevant only in a structural/obstruction sense; functionally, if it protrudes at all, it’ll work.
Also, I can’t imagine that leaving the toilet seat down would have any effect unless the toilet bowl is dirty and therefore the source of the smell in the first place. Assuming your toilet bowls are cleaned regularly…
A dry trap will indeed allow a nasty smell to get into the house. But this is seldom a problem with toilets, since modern toilets are essentially giant traps; as long as there’s water in them, you won’t get a backwash of sewer gas. And I doubt if a leaky wax ring is the culprit; the universal symptom there is water all over the floor or coming through the ceiling of the room downstairs.
I helped my parents build a new house some years back, and to this day my dad bitches about the plumbing. One of his complaints is a nasty sewer smell, most noticeable in the basement bathroom, and particularly after someone upstairs flushes a toilet. I did a lot of the plumbing work, including installing the waste stacks and vent, and he likes to claim that I screwed it up, or that I should have installed more vents, and whatnot. I took the time to chase down the yahoos who poured the basement floors, and it turns out that the basement shower drain has no trap at all. Duh.
True, however, we were not just talking about the toilet trap. Every single sink and drain in the house, with a few exceptions, has a trap in it which, if it goes dry, can let gas into the house.
My last paragraph was meant to be an illustration of what happens in a situation where there is no trap at all; a dry trap = no trap at all. We agree, yes?
At the moment, I’m in the middle of renovating a 120±year-old house, and I can tell you for a fact that providing traps was not necessarily high on the list of the plumbers of the distant past! We have a floor drain in the basement that ties into the “main drain,” the sanitary sewer for the house. It is nose-curlingly clear that there is no trap on that floor drain!
