Mysterious Sewer Gas Smell

[jodyjl]

We bought this home in April 2007. We began noticing a sewer gas smell once in a while. It was not in any particular room. It seemed to be EVERYWHERE. We work out of our home and so we are here 95% of the time. We notice the smell mostly on weekdays in the evening about 6pm. We have checked the vents for the bathrooms and cleaned them. We have checked the attic for leaks in the vents and found none. We have checked all pea traps to be sure they are installed and full of water. We have checked the a/c condenser drain pipe but it drains directly outside. When this smell happens, we are normally gone and come back into the house to an overwhelming smell of sewer gas and it will linger for 3-4 days. We are thinking about installing a vent in the main sewer drain outside to see if that would help but it doesn't make any sense that it would. How can the gases be getting past the pea traps? The only common activity that seems to be tied to the smell is I will do laundry --like yesterday morning. I did two loads of laundry, cleaned house all day, had friends in about 3. No smells. Went out to the pool and swam for 45 minutes--came in to a moderately bad sewer gas smell.

Does anyone have any ideas of what could be causing this?

 

[Softus]

Firstly, it's quite possible for sewer gas to make it's way through the water seal in your WC, basin, sink, shower and bath wastes.

Secondly, nobody is going to pinpoint the answer to your problem without any details of your plumbing system.

 

[jodyjl]

I am not sure what details of my plumbing system you would need, but the house sits on a slab. We are are city sewer. Does that help?

My husband found a "clean out" in the main sewer between the house and the main city sewer line. It was just a hole that was made in the PVC pipe and covered with a piece of metal. In other words, not a closed system. The soil is actually sand so if there were a build up of gases in the city's main line, we think the hole would have allowed the gases to escape before getting into the house.

 

[Softus]

I am not sure what details of my plumbing system you would need, but the house sits on a slab. We are are city sewer. Does that help?

No. What I'm looking for is:

1. How many sanitary units drain into your private sewer run.
2. How those wastes are all connected.
3. How long the waste pipes, e.g. from basin to connection point of sewer.
4. Whether or not there's a vent to the open air at high level.
5. Whether there are any air admittance valves.
6. Any other information that you might think is relevant.

My husband found a "clean out" in the main sewer between the house and the main city sewer line. It was just a hole that was made in the PVC pipe and covered with a piece of metal.

Well that's not a good thing. In the UK that would be illegal.