Re: Sewer Gas Smell In Bathroom
Posted by angelo on July 29, 2003 at 10:47:57:
In response to Re: Sewer Gas Smell In Bathroom
: WE have a 40 year old building and our ladys bathroom is emitting a sewer gas smell. I did notice the the sink trap has a lot of activity in it when looking down into it with a flash light. Also when the trap is empty their is a force of air blowing in to the room. The roof vent is open I checked it. Do you have any ideas?"
Hube hit it on the head. The traps should never be empty. To understand this, you need to understand how traps work and why they are there.

Some people think traps are there to trap items that you drop down the sink. Not at all. There are there to "trap" a plug of water to act as a stop for sewage gasses from the sewer system. With the traps filled with water, gases are allowed to escape up thru the "dry vent" pipes .. which should be connected just past the traps and extend up thru your roof and out into the open air.

When you flush a toilet or open the drain in a tub or sink .. a solid "block" of water fills the pipes .. creating a siphon. Without an open drain pipe and vent pipe .. the vent pipe can't break the siphon and the draining action will actually suck the water from the trap. If this clog is bad enough .. a flush or drain can actually suck the water from all the other connected vents (you flush the toilet and it can train the trap in the sink).

Another way that you can loose trap water is thru a slow leak at the bottom .. you should investigate this if you can.

Assuming that the building was built to code and the drains are propery and that the traps are not leaking .. then your problem is probably a clogged pipe or vent. You should snake all the pipes that are connected .. bath, sink, toilet. I would follow that up with a foaming, snaking drain cleaner that is safe for your type of pipes.

If you have access to the roof and the vent, you might want to snake down the vent pipe as well.


Replies to this post