Toilet issue -- am I on the right track?

I have a low-flow Kohler toilet that’s been acting up. Here are the symptoms: poor flushing, low water level in the bowl, and most of the time there is an air bubble that blurps out as soon as the lever is flushed.

At first I thought it was just a clog, so I used a toilet auger. I used the full length of a 6 foot snake, and it helped a little bit – there were not any obvious obstructions. I can’t use a plunger because the bottom of the bowl is slightly oblong shaped and does not form a good seal.

After a little googling, I found that the bubbles at the beginning of the flush are probably caused by an obstruction in the vent line. I read that this can be diagnosed by pouring a bucket of water into the bowl and seeing if the water level keeps rising and air bubbles are being released as the water is going in. My plan is to try that tomorrow, and if I see bubbles, head up to the roof and try to snake it out with a 30’ snake I have.

Am I on the right track here? Any other suggestions? I’d rather not pay a plumber to come to the house because this doesn’t seem like rocket science, and plumbers are quite expensive here in DC.

We had an issue like that earlier this month. It turned out to be a big clog in the septic system, nothing wrong with the toilets themselves.

If this is a recent development, yes, the vent and/or waste lines are probably the problem.

Would a plunger with the extended cup work on that bowl?

If this developed as soon as the toilet was installed, then you should be looking at the toilet. The low-slunk Kohler I installed never worked all that well - it need more water pressure than the house could supply.

Lesson: no more low toilets.

The toilet has been working fine for more than a year. I should also mention that I don’t seem to be having trouble with any other toilets or faucets in the house.

I will check into the extended cup plunger, I had never heard of those before.

When you are looking at the vent line check to make sure there is a screen or something to prevent junk like leaves from falling into the vent and clogging it up.

If you’re having winter weather like we are, watch for slick spots on the roof!

Naw, it’s like 50 degrees today and the vent is on a flat part of my roof. I’m just a little puzzled why, if it is a vent problem, only one toilet would seem to be affected.

The other toilet has some sort of a vent. There may be a proper vent for it.
Or it might have sucked the water out the S bend in a nearby pipe (eg floor drain), and turned it into the vent.

Or just because the pipes there leak air in or out.

Or just because the horizontal pipe has a large volume that means the pressure change caused by flushing is not significant.

a screen on a vent pipe is not a good idea. it’s a building platform for a bird’s nest, bugs and flies will nest on it. it would plug up quickly.

Is a snake the right thing to use on the vent? I also read online that a garden hose (with or without one of those pressure bulb things) can be used. But I’m not sure I have a hoses that will reach…

Do you know if the problem toilet is the one closest to the outgoing sewer line?

I had a problem similar to yours with one of my toilets (poor flush, bubbling, etc.), while the other one was flushing and draining fine. It turned out to be roots growing into the septic line, near where it left the house. A plumber made a few passes with a power rooter through the cleanout pipe and it cleared things up.

I fixed it. I snaked the vent and came across two small clogs – both were disposed of quickly, but I had a feeling they weren’t actual obstructions.

I flushed the toilet again, and still with the bubbles. I went back to step one… and discovered that the 6" fill tube was dislodged and emptying incorrectly into the tank. Snapped that back into place, and everything is perfect again.

It was a nice day to be on the roof and have a view of lovely DC, though!