Washer drain backflows to sink and shower

[dom]

My mother just had a full bathroom installed and is experiencing the following problems. Each time the washer drains there is backflow through the bathroom sink and shower stall. Occassionally the toilet bubbles as well. The bathroom is situated next to the wash room. I've been told a "p-trap" may not have been installed properly (if at all), or that the sink and shower drains were tapped into the wrong line. Could either of these suggestions be the cluprit, or is it something else? Unfortunately, I wasn't made aware of the problem until now and the installer is no where to be found. Any help is appreciated.

[Rich]

Sounds like either of those could cause it. If it was tied in incorrectly the venting on the washer side could now be incorrect also.

[dom]

Rich - Thanks for the reply. Where would I go to find more information and repair tips? I performed a google search which resulted in thousands of "matches" but I've yet to find a solution. Thanks again!

[Rich]

Is there anyway to take a couple pictures of it and post it? And possibly call out what you think comes from where and goes to where?

[dom]

Is there anyway to take a couple pictures of it and post it? And possibly call out what you think comes from where and goes to where?
I'll try and get some pics up this evening.

[Tom R]

Sounds like he didn't vent the bathroom drains properly, and/or your drainline is clogged (from the improper venting). Is the washer draining into a 42" high standpipe with an 'open' top and a trap? Is this in your basement or on the 1st floor, or what?

[dom]

Sounds like he didn't vent the bathroom drains properly, and/or your drainline is clogged (from the improper venting). Is the washer draining into a 42" high standpipe with an 'open' top and a trap? Is this in your basement or on the 1st floor, or what?
Tom - The washer does drain into a high standpipe but it's 36" from the floor. There isn't a p-trap attached directly to the standpipe but there is a p-trap under the washtub to which the standpipe leads to/from. Please refer to the pics (you'll have to excuse the pink...the house was built circa 1940 8) ). Everything is located on the bottom floor of the tri-level house with no basement. I should note that my mother has never had a problem with the washer drainage pipes until the bathroom installation.

With regard to the bathroom, none of the pipes are visible except for the p-trap under the sink. It appears they were ran behind a wall which is adjacent to the washtub in the pic. Thus, I didn't snap any pics of the bathroom.

Looks like I'm going to have to take out the wall to determine where the shower and sink drains are leading to/from. What should I look for while I'm in there?

[mjpliv]

Without a p-trap on that washer drain you are venting sewer gas directly into the house. My guess would be a restriction in the common drain under the floor. That pipe going into the wall is probably your vent line. Unless it is plugged or restricted it is unlikely to be the culprit.

[dom]

Without a p-trap on that washer drain you are venting sewer gas directly into the house. My guess would be a restriction in the common drain under the floor. That pipe going into the wall is probably your vent line. Unless it is plugged or restricted it is unlikely to be the culprit.
mjpliv - Thanks for the response. There's never been a problem with washer drainage or odor problems until the bathroom install. This leads me to believe the culprit(s) to the backflow of debris into the shower, sink, and toilet (while the washer drains) lie somewhere in the bathroom plumbing. But then again, maybe the washer drainage is plugged up somewhere...What is the most likely culprit and what should I check first??? I am not liking the thought of ripping a wall apart... :?

[mjpliv]

I would pull the toilet in the bathroom out and run a large bore snake downstream to clear a suspected restriction.

The washer may be the only thing that indicates a problem because everything else drains by gravity while the washer output is pumped. The larger volume of water could cause a main drain restriction to become apparent.

[Tom R]

What mj says is the most practical way to start the 'process of elimination', the last thing you would check (if you can't find any other problem) is where that vent goes. Unless that vent goes directly outside, through the exterior wall somewhere, it shouldn't connect into another vent line until it's above the water level of all other fixtures in the house. Also, that vent line going into the wall, in all reality, should be one size bigger (in other words, if your drain lines are 1 1/2", your vent line should be 2"). I would wager he vented as close as possible (a 'wet' vent) which is usually not suggested/allowed.

[mjpliv]

I wonder if the guy put the sanitary Y's in backwards in the bathroom? I suppose that will be found out when you try to feed a snake through the system.