Venting?

[PJM1]

Hi,
I live on the second story of an eight story condo complex with 98 units. My unit is at the end in the corner. In one of my bathrooms I get laundry soap backing up through my toilet and out my tub drain. The management company keeps sending plumbers to snake the line but I think it might be a venting problem. The toilet in the second bathroom has a slow flush and the kitchen sink use to have water back up thought the drain until there was a check valve installed.
Presently the only issue is the laundry soap. What do you think it could be, how can I have it inspected to verify the issue and what do you think I can do to correct it? This problem has been a problem for a couple of years.

Thanks
Paul

[jimbo]

Multistory buildings are a different animal, and I have no experience there.
FIrst question: Is the suds from when YOU are running a washing machine in your apartment, or is it from a common laundry, or coming at times you are not running the washer?

Venting is not the first thing that comes to mind. What I might suspect is that the laundry drain is not installed correctly, or is undersized.

I think some other guys will offer some more specific advice. You will probably have to find a plumber who is familiar with your building.

[PJM1]

Every unit has its own laundry and it does not happen when I do laundry. I always happens on Friday or Sunday!

[Gary Swart]

Once again I stand in support of Jimbo. I suspect the drain for the washers is too small. In a single family unit, 2" is required for new machines. What you would need in a multistory building, I have not idea, but it sounds to me like there are too many machines dumping water at the same time into a drain that is undersized.

[hj]

There are many interrelationships in a multistory building, but venting is usually not the cause of your symptoms. If it were there would be ABSOLUTELY NO WAY to cure it. You probably have what is know as "suds explosion", although it usually occurs on the lowest level of a multistory building, unless you building has a hybrid drainage system and you are the lowest level of the gravity portion of it. If this is the case, then it is because of an improper, or at least unwise, connection point for your drainage, and it is also expensive to correct. Your problem probably started when someone upstairs decided to change to a high sudsing detergent.

[PJM1]

There are many interrelationships in a multistory building, but venting is usually not the cause of your symptoms. If it were there would be ABSOLUTELY NO WAY to cure it. You probably have what is know as "suds explosion", although it usually occurs on the lowest level of a multistory building, unless you building has a hybrid drainage system and you are the lowest level of the gravity portion of it. If this is the case, then it is because of an improper, or at least unwise, connection point for your drainage, and it is also expensive to correct. Your problem probably started when someone upstairs decided to change to a high sudsing detergent.

Thanks
I think you hit it right on the head. It only my unit is on the lowest level at the end of the building where the drain exits the building. It also happens at the same time every week and it seems to have stopped since we spoke to someone that was using High Efficiency soap improperly. Is is something I can fix if It does not stop?

[Winslow]

Thanks
I think you hit it right on the head. It only my unit is on the lowest level at the end of the building where the drain exits the building. It also happens at the same time every week and it seems to have stopped since we spoke to someone that was using High Efficiency soap improperly. Is is something I can fix if It does not stop?

The suds float on top of the draining water, as the suds increase in volume they make their way back up into your unit. The only sure remedy besides convincing the people above to use a low sudsing detergent is to move.