I am connected to a sewer system. When my washing machine emptied into a double sink in the basement, my toilet, which is about 30 feet away, backed up. I ran the shower and sink on the first floor and flushed the commode on the first floor, and it had no effect on anything in the basement. The sink the washer empties into now ( a day later) has standing water which eventually empties. So obviously since the sink empties at a snails pace, there's no back up in the commode. I can still run and flush on the first floor with no apparent problems. Can anyone put a finger on what's causing this?

Hey Kool... start by looking around at pipe that comes from upstairs and see if can find a way that pipes by pass the basement pipes (such as coming out of ground and heading upstairs wayyyy before basement drains?? ).

Next, if nothing obvious, I want you to really flood the plumbing system. YOU will need 2 people here. One goes upstairs, turns on all fixtures, flushes toilet.. and keeps doing this for 5-10 minutes.. second stays in basement watching toilet AND laundry sink.

See, laundry sink may already drain slow... so do not concern yourself with that yet... flood the system... AND THAT TAKES time.. so fill away, flush away.. see if can flood your main.. then you will know it is your main drain line. WHY does washing machine flood?. 'cause large volume of water all at once... flood via washing machine and then flush toilets upstairs for a few.. again... have friend standing by ;)

IF you can find the main drain cleanout.. remove that if you can... and do this flooding of plumbing I am talking about.. IF water shows up at cleanout.. just confirms what I am saying.

WHY am I leaning toward main drain... cause laundry tub And/Or toilet filled with water is sign of main drain clog.. USUALLY. AND usually customers do not flood system enough to tell that whole house is involved (picture all those pipes filling with water... if slow clog.. can take awhile before finally backing up).

ANyway... you did say you were on sewer system... NOT SEPTIC right (per your post)?

Hey , look around, try these tests, see if anything gurgles when using first floor fixtures, etc. Get back to us!

Thanks for the Quick reply, Mass. Yes I am on a sewer system. I'll have to do this tomorrow afternoon when my son is here. I'm not sure what or where a cleanup drain is, but there is a 2-inch nut on the floor about one foot in front of the pipe going into the concrete floor from the sink. The nut seems to be on a pipe going into the floor. Would this be it? It looks like it will be hard to open, but I'll give it a shot. I'm finding it difficult to follow the pipes coming out of the first floor into the basement ceiling. But I will email back my results tomorrow. Thanks again.

YUP that plug may be it.. I hope.. and yes.. will be hard to open. I would use an 18 " pipe wrench. The MAIN DRAIN cleanout is larger.. say 4 inches across... it should be on the street side of your building in the floor or just outside foundation at ground level... it will also be hard to get out... Keep us posted.

OK Mass, here is what I did and the results of those actions. Being anxious to get these things resolved, I did a few things before my son came over. I hope none of these things masked what might have been the original problem.

First of all, I did not see any pipes coming from or going to the ceiling that I couldn't account for. Just out of curiosity, what size pipe should I have been looking for? This is a finished basement however, and ceiling tiles and some structures hide a lot of eyesores. In fact, there was a paneled structure in a corner of a room downstairs, that went from floor to ceiling. The floor of the basement is about 5' below ground level, by the way. It was about 2' x 2'. By my estimate, it was directly below the bathroom on the 1st floor. So this could be hiding the pipes you had me looking for. Also, I walked all around the outside of my home, and other than two faucets on either side of the house that I attach water hoses to, there was only one other pipe I could see. It was coming straight out of the concrete wall, just above ground level outside the laundry room. It looked like a vent pipe, that had a rounded fitting at the end that pointed it downward. I saw nothing that might be a drain cleanout pipe. The one in the floor by the sink was the only one I could find. And now looking at that, it was more like 3 or 4 inches across, not 2 like I had indicated yesterday.

The first I did this morning was go into the basement bathroom that is backing up, and noticed there was what looked like it might be a vent pipe, it extended about 6 inches above the floor, between the wall and the commode. I unscrewed the cap, and water came gushing out. But only for about 10 seconds, then it settled down and after cleaning up the water, looking into it, I could see no more water. I then open the cleanup drain, which wasn't as hard to do as I thought, and again water came gushing out. It had particles in it that looked like they might have been the remnants of paper towels that had not biodegraded. After I cleaned the water up, I looked into it and I could see standing water, just below the floor surface.

Now we did as you had requested, we flooded the system with water from the first floor. The toilet, the bathroom and kitchen sinks and the bathtub. Although the water in the drain cleanout seemed to ripple a little, there was no rise in the water level. Nothing changed in the pipe in the basement toilet. Then I filled up the washtub, and it emptied quite normally until there was only about 1/4 inch, at most, left. Then it sat there for a minute or so and eventually completely drained. I don't know if any of this was significant because there were times during the last few days that I could not recreate the situation, and then suddenly, it was back.

The last thing I just did, was run two large loads of water through the washer. The first time there was only standing water in the commode, but it did gurgle. I filled the toilet up then (for other problems, unrelated to this, I have had to shut the water of at the toilet and the only way to flush it is to quickly pour a bucket of water into it) and the second load also gurgled, but did not overflow.

Anyway, there are 2 abnormal things wrong with this system. The gurgling is one. The other is that when the one half of the double sink starts emptying, the other half starts to fill. Not completely, maybe a half inch, before it empties.

Sorry for being so wordy, but I would rather give you too much info, than not enough. Do you have any idea what might be causing my problem? I really appreciate your time. If you need any other info please let me know. Thanks!

That 3 or 4 inch plug /cap is probably your main drain cleanout...

You say you found pipes that had water that overflowed when you accessed them... that suggests a good place to snake the drain from. That 6 inch pipe in bathroom... send a snake down that drain and see what you find... that should help you.

I am a little confused by fact that flooding system did not cause pipes to back up, but does not matter at this point. Rent a medium size snake (3/8" or 1/2") and send it down the pipe you uncovered at bathroom... sounds like some paper towels got down there and clogged stuff up (could be roots somewhere outside... ). If you don't discover anything then it may time to call in the pros! Keep me posted.

Thanks, Mass you have been a big help. One of my friends had suggested the root problem, which sounded very costly. But I'm thinking if the problem was in the yard, why wasn't it backing up when the system was flooded from the 2nd floor? I will take your advice, and rent a snake. I can't tell you how helpful you were, and how much I appreciate your valuable time. I understand a lot more about plumbing now, than I did yesterday at this time. I will post when I get a resolution. Thanks again!

I just hope the problem is inside like YOU are hoping. Keep us posted over here.. and please wait a little and see what some of the most experienced posters have to say on this matter (they know who they are ;) )

You know some of them aren't even plumbers.. just smart people with life/work experience.. so give 'em a day or two to post. Like I said... let us know. Good night.