Thanks for he opportunity to get help from experts through this forum.

I have a two year old house with a basement rough in that consists of a 4 inch pipe about 16 inched from the wall. There is also a smaller pipe about 4 feet away that is supposed to be used for the sink. Running up the wall about two feet from the large pipe is a vent pipe that connects to the main vent running the length of the house.

I would like to install a small bathroom but when I pulled the cap off the large (toilet) pipe about two gallons of water rushed up and out. The water smelled stale but was clear and not like sewage. The cap was not glued so it did not take much effort to pull it off. The water went down and I put the cap back on. Since then I have noticed some seeping from time to time.

I’m ready to start working but before I start the job should I have my main drain checked for blockage? There is a washing machine drain about 15 feet away that is only about 12 inches higher than the bathroom pipes and I have never had any problem with water backing up there. I don’t want to open the bathroom drains and have a flood. What is your advice?

My question is whether you know how the pipes in the basement drain. Is there reason to believe it is just gravity fed out to the street or is there perhaps a pump involved with the drain at that point. If it is gravity fed and you want to be sure there is no blockage, why not hire a company to camera the line?
Darrel

Hi Lou,

"There is a washing machine drain about 15 feet away that is only about 12 inches higher than the bathroom pipes and I have never had any problem with water backing up there."
Please explain what you mean. The washer stand pipe is a foot above the lowest drain,( tub or shower)?

Why not take the cap off the 4" toilet stub up and cycle the washer. If it backs up you have a clog farther on downstream in the sewer line and it needs to be snaked. I don't get the impression that there's a sewerage pump involved or you would have more problems then you have indicated. Darrels idea of running a camera down the line has merit but if it's a partial clog you're going to end up snaking that line out. Regards, Tom

Thanks for the advice,

The washer pipe is about 12 inches higher than the lowest drain in the rough in. The washer drain pipe runs about 6 feet and connects above ground to the main drain. I assume the rough in pipes connect to the same main drain below the concrete slab.

I’ll uncap the pipe and run the washer and some other water sources to see if a backup occurs.

Thanks again.