Sewer gas

[Anonymous]

Posted by: ctyankee (old forum transfer)
Posted - 04/30/2002 : 07:59:08

I have 2 bathrooms on the 2nd floor back to back, serviced by a stack in a wet wall between the 2 rooms. When the toilet in bathroom 2 is flushed, the water in bathroom 1 toilet and shower stall both move up/down by up to an inch and thereafter I have a sewer gas smell eminating from the shower stall drain. Any ideas?

[Anonymous]

Posted by: Wgoodrich
Posted - 04/30/2002 : 12:34:19

You either have a vent to those outlets inadequately sized or inadequatley placed or you have a wet vent that is plugged.

Check for a plugged wet vent then if you find no plugged wet vent then calculate your units concerning sizing of that or those vents and / or distance of the vent from the outlet.

Your plumbing can not breath causing a suction from the flowing waste water that is sucking your J-traps dryer allowing sewer gas to enter the dwelling through the empty j-trap.

Hope this helps

Wg

[Anonymous]

Posted by: ctyankee
Posted - 04/30/2002 : 12:59:54

Thanks for your reply, but what do you mean by a wet vent? and how do I check it if the plumbing is not accessable from below? Also, the house is 10 years old and this problem has only been happening for the past 3/4 months

[Anonymous]

Posted by: Wgoodrich
Posted - 04/30/2002 : 13:54:38

A wet vent is commonly used when venting a couple of outlets like a sink and shower. Most often you will find the vent going up through your roof. Problem is often times vents are connected to a bigger pipe that shows through the roof yet are coupled together within the wall.

Look to see if you have a shower or vanity that is slow of plugged while draining. Most often the problem will be there.

Try taking your shower screen found in the floor of your shower out. See what direction the pipe heads. Probably will head toward the second shower. Then remove the screen in the second shower and see if that pipe heads toward the other shower. You will probably find both drains are connected together with a wye in the adjoining bathroom wall. Go outside and see if you have a pipe going through the roof directly above that adjoining wall between those two bathrooms.

Picture the two shower drains connecting together then connected to a pipe going down to the crawl space serving as the drain pipe for both showers. Most likely the vanities are also connected to this larger pipe going down to the crawl space below. What I suspect you will find will be another pipe going straight up acting as the vent where these separate units connect to that drain pipe serving all the units.

This pipe is called a wet vent. This pipe serving serveral units not only act to guide the water into the crawl space but also allows are to enter the system to stop the pipe from syphoning the other units trying to get air as the water goes down that bigger pipe. If this wye is plugged then the vent is doing you no good and the drain system is pulling the water out of your other units such as stools, vanities, shower drains to get its air release to stop the weight of the water flowing down the pipe to suck water out of adjoining pipes.

I suspect you will find the pipes plugged where the vent pipe is connected to hte system. You should be able to get a good idea where that vent connects to that drain by looking on your roof and seeing if that vent through the roof is over that adjoining wall that is stacked over a wall below for a path for these drains to get down to the basement or crawl.

You may not like it but you will probably have to open the wall and replumb around that older drain especially if this is metal drains. There is a rubber boot that allows you to cut out the corroded bad pipe sections and joints and use the boot to change to plastic for ease of replumbing that bad piping area.

Hope this helps

Wg

Most likely you plgged