I have a 1963 5 gallon toilet that is doing something weird. After flusing (toilet flushing fine), the toilet bowl will slowly drain or lose about an inch of water in the bowl. It drains out the inch in the first minute or two after flushing and you can see it going down in the bowl. Remaining in the bowl is plenty of water to flush and this seems to be operating effectively. As a precaution, I replaced the flapper but this didn't help correct the problem.

Any ideas? Could it be a clog and if so, how do I verify the sewer is not getting plugged? Like I said, it is flushing fine.

I did have a licensed plumber out to look at it and he said it's fine, although he said my toilet was very old.

I am very worried about it however, as it is the only toilet in the house.

Thanks in advance for your advice.

I suspect that the drain either does not have a vent or the vent is clogged. When the toilet is flushed, there is a vacuum created by the water rushing down the drain and that will "pull" a little more water with it after the bowl has re-filled.

Do you have issues with water draining from the vanity or tub?

If it were vented properly, how would that prevent what you are describing, at the bowl?

Especially since it takes a minute or so for the water level to drop.
What happens if you pour enough water in the bowl to raise it to it's original position without flushing it ?

Actually, I do have trouble with water draining from the tub and the bathroom sink. Sometimes I put the liquid plumber down the sink drain which helps for a while. Do you suppose there could be a stoppage?

And about 4 years ago, when I bought this house, the inspector said there were tree roots in the pipes. I was afraid to pursue that at the time and I have 2 giant trees in the front yard.

The house was built in about 1930 and is on a 3 foot tall foundation with the pipes underneath.

Am I just being stupid and it's the roots?

Thanks.

OK, check this out. I poursed 2L of water into the bowl and the bowl didn't hold it. Somehow the water level never rose. There was now obvious sounds/gurgling and I didn't see any water movement to speak of.

What could that indicate?

Try using a plunger on the toilet. It's a longshot, but if something has draped itself over the weir of the toilet, it could wick the water down in the bowl.

OK, plunged the toilet and flushed it and it continued to drain away about an inch of water. After the bowl filled up, it held the water about 15-20 seconds and then the water level dropped. It was as if it got sucked out of there.

It drops the 1" rapidly? The flush has finished, there's no more sound of running water, and then the level drops?



Edited 1 times.

Yes, it drops the 1" in about 10 seconds. I just checked it again and the tank fills kinda slow but without issues and once the tank finishes filling and the water stops coming into the tank, the water drains out of the bowl in about 10 seconds. There might be very minor current or movement of the water as it drains the one inch but no water flow noise.

This all started yesterday after my shower. I wonder if that has something to do with it?