View Full Version : Bathroom drain problem - sharing with garage floor drain

06-13-2011, 05:52 AM
Hi everyone,

I hope someone here is able to help. There sure seem to be a lot of knowledgeable people posting in here!

We have a house built in the 1950's that had a bathroom added to the room above the garage in the 80's. The problem is I believe they tied the new bathroom drain into the line that has the garage floor drain, and they tied in before the drain. What is happening now is that sewage, toilet paper, etc. is finding its way up the floor drain and into the garage. I had a backflow preventer valve installed there, but it eventually was broken by the pressure of the sewage. The bathroom drains fine and there are no backups in the toilet or sinks, however I fear that this accumulation of sewage in the vertical pipe that ties the garage floor drain to the main line is eventually going to cause a problem. Also, there is a cleanout for the garage floor drain but that is also clogged with waste matter.

Can anyone recommend a fix for this? Should I try and have the garage floor drain capped down the pipe where it meets the main line?

Thanks for your assistance!

06-13-2011, 06:08 AM
You have a blockage in the drain. THere is plenty of pipe to fill up downstream, so you don't notice a problem with the flush.

Although not required in 1950, it IS required today to have a floor drain in the garage, so you can't just close it off.

06-13-2011, 06:12 AM
Thanks for the reply, jimbo.

Where I live (Ontario Canada) it is the opposite - floor drains are not allowed in new construction because they encourage people to dump oil and other waste products into the sanitary or storm sewer system, so rendering this drain non-existent would actually be ok.

So are you thinking that the problem is further down the line, past the garage floor drain and closer to where the drain meets the city system? What would you recommend as the best course of action to resolve the problem and prevent future recurrence?

06-13-2011, 07:17 AM
Whether you close off the drain or not depends on whether you want a "pond" in the center of the garage around the drain. Closing the drain, like installing a backwater valve, just eliminates the SYMPTOMS, it does NOT cure the real problem. What you describe SHOULD NOT happen, but there are many reasons why it does, ranging from a bad installation to a partially clogged drain line. Backwater valve are NOT destroyed by back pressure because that is what they are supposed to resist.

06-13-2011, 09:55 AM
Thanks for the input... So would you agree that a floor drain should not be present in line with a bathroom drain? What I am hearing is that the problem is likely partially clogged line, which my findings would indicate, so I am thinking I will have the line professionally snaked and/or opened up, but then I want to know if you all agree that eliminating a floor drain and cleanout in-line with the bathroom drain is the proper solution to make the system as sound as possible.

06-13-2011, 11:24 AM
I have read your post 10 times and if they tied it in before the floor drain( how I don`t know), it might going through the trap of the floor drain.
You should keep a clean out.

06-13-2011, 02:10 PM
quote; but then I want to know if you all agree that eliminating a floor drain and cleanout in-line with the bathroom drain is the proper solution to make the system as sound as possible

NO! If the system was installed properly, and it is working the way it should, you will NOT have the problem until it needs servicing again, and that will happen regardless of whether you have the floor drain, and will be more difficult to correct if you eliminate the cleanout.