I have a new home. Toilet in master bath doesn't always fill up in the bowl. When it does fill up, the water will gradually drain out. The plumber has done the following:
Changed the ballcock, changed the refill tube, changed the toilet bowl (twice). The second toilet bowl was replaced with a 10 inch rough-in(?). It seemed to work a bit better after that but only for 1 day. They have since ran an auger down the vent pipe. The plumber stated he didn't feel a clog.

The next step is to run a video camera down the line they said.

Does anyone have any thoughts of what the problem is?

Melinda

No, but I should get another plumbers opinion first instead of paying the one guy for all that work, if the other plumber finds nothing too, then carry on with whatever they suggest.

There are only a few ways this could happen.
There could also be a factory defect in the bowl. Sometimes in casting the bowl there is a small bubble in the china. Instead of junking the bowl the manufacture will put a porcelain patch over the hole and send it on through. On occasion the patch will fail allowing the water to seep out of the bowl. If that's the case you would have a full bowl after you flushed and the bowl filled but some time later you would notice a drop in the bowl level. The only other thing might be if you dropped something in the bowl and cracked it. If you're worried about where the water's going, in both cases it drains back down into the sewer and not under the bowl on the floor.
Sometimes a blocked vent can "vacume" water out of a bowl. Does the level "bounce" up and down?
The bowl could have been cracked during shipment or installation. If the crack were internal then you wouldn't be able to see it.
But wait! You said you replaced the bowl and the same problem persists.
This kind of take the blaime away from the toilet doesn't it? Two cracked bowls or two bowls with a manufactures defect kind of stretches the imagination. Possible but not very probable!
What's left? A clogged vent would do it. I know you plumber said he checked the vent but (1) did he just look down it or did he snake and clear vit. If he snaked did he put out enough cable? **or** (2) did he check the right vent?
I've given you all the possibilities that I know that would cause this problem.
Now it's up to your plumber to sort them out. HINT! Go back over the vent and check it out real good. Best of luck, Tom

The plumber did snake the line, he said that he put in 100 feet! The water doesn't go up and down. When it fills up, it will have some air bubbles, then gradually go down, eventually stopping. Since I am still under the builder's warranty I haven't had to pay for any of this work. But I'm glad it is a different plumber who is coming today to put a video camera down the line. I hope he can fix the problem.

M

OK! If he went down the correct vent then this is beginning to sound more and more like a faulty bowl. I had the same complaint as yours, new toilet wouldn't hold water in the bowl but had no leaks on the floor. The only way to check for a hidden leak in a toilet bowl is to pull the bowl, set it up on blocks and fill it with water. You'll soon find out if the bowl's faulty or not. And I think that should be your plumbers next step.
Please keep me in the loop. I'm as interested as you to find out why the bowl level's going down. Regards, Tom

Speedball,
Well the plumber put in another brand of toilet today. A Vitra brand. It is a powerful flushing toilet, but... it doesn't seem to fix my problem. The plumber who did the house is stumped. He is positive that it isn't a vent problem because everything drains okay, no gurgling. We filled up the two sinks, bathtub and then opened stoppers and flushed the toilet. Everything went down okay. He says that he knows he vented the toilet off the lavatory and it was within the 6 feet recommended. He is positive that it isn't a venting problem, but I think that is the only thing it can be (or a clog).

We are going to run a camera down the line. This problem just doesn't make sense to me, why would a toilet bowl fill up with water, then gradually (about 1 minute) the water goes back down. We've changed the bowl 3 times, the tank, refill tube, ballcock.

Thanks
Melinda

How much water drains from the bowl? Did the plumber check to see if the toilet was level front to back? I installed a new toilet and though it was seated against the floor for some reason it was not level and was pitched towards the wall. After flushing, the bowl would fill and produce a good water surface but then slowly drain about 3/4". I could hear water slowly draining I'm assuming because of the pitch. After leveling, the problem disappeared. Maybe this was a unique situation but just something you might look at...

Thank you Shader for giving us a new slant on the problem. This is one I've never run into but it's another possible explanation. It just goes to show, you're never too old to learn. Mdbasnger, could this be the root cause? Regards, Tom

Well - they think they have figured out the problem. I have a "backfall". The water stays in my pipe. They ran the video camera down the line and that is what they have determined. To fix the problem they are going to have to dig under the house and re-do the pipe.

I'm unsure whether to have this done but am leaning towards having it done as the house is under warranty. Also I'm not sure what problems this might lead to down the line.

Thanks for all the suggestions and help.

Melinda

Well, I was close, something was slanted the wrong way:) But what does the plumber mean by "backfall" ? If water sits in the pipe it's not pitched properly. Backfall? Is it creating a vacuum and drawing water from the bowl? Also, where is this "backfall" located? If it's right by the toilet I guess it could create some type of problem, but if it's way down the line not sure if that would be the cause as you stated all the other fixtures work properly. Hopefully Tom can shed some light on this.

I have a problem with the "backfall" explanation. If the sewer had a bell in the line then it would act like a running trap and set up a back pressure as well as slowing down the flow. How would that set up a vacuum that would suck water out of the bowl? In my opinion the plumber ran out of ideas and fixed 0on the first thing he found out of the ordinary. Personally I think the [plumber's still "stumped". I don't care what anybody sez. If the toilet's vented correctly then nothing downstream of that toilet will pull water out of the bowl. If I'm wrong here, then I'm waiting for somebody to correct me. Regards, Tom

Speedball,
This is what was explained to me. A second plumber came out (not the one who plumbed the house), he ran a camera down vent pipe and didn't see a clog. He then ran the camera down the line inside the house (toilet removed). He said there was water standing in the pipe. Somehow this standing water was cutting off the air to the vent and causing the water to be sucked from the bowl.

What they are now going to have to do is dig down (6 foot?) and then go under the slab to fix the fall of the pipe.

Thanks again for your input.

Melinda

As I see all this, you are indicating the branch to the toilet has the back fall? Since it is only 6 feet from the vented line that means the bell [belly] in the pipe is backfalling at 1/2" per foot. Doesn't sound right. I tend to agree with tom on this one. Have the first plumber view the tape recording of the camera.

"The plumber said there was water standing in the pipe. Somehow this standing water was cutting off the air to the vent and causing the water to be sucked from the bowl."

That doesn't fly either. If that were the case wouldn't the water be sucked out of the lavatory and tub trap since they have less water to be sucked out?: Even if the standing water was deep enough to fill the pipe the fixtures would still be vented. I think your plumbers have run out of ideas and excuses and are blowing smoke. Regards, Tom