I hope someone can tell me what else to try. I am redoing a bathroom in a 50 year cabin. The old toilet flushed strong, but there was a "gurgling" in the other drains. When I removed the old toilet I replaced the flange. The old flange had 3" pvc inserted into the 4" cast drain with some plumbers putty sort of filling the gap.

I installed a new flange with a "two finger" gasket into the 4" and it is sealed tight. I installed the new toilet and when I flushed, the bowl would quickly fill with water and then slowly drain down to the proper level (in a minute or so). I pulled the toilet and set it up on some 2x4s in the back yard, filled the tank with a hose and flushed it several times. Not the problem, flushes great. I then dumped 3 or 4 gallons of water directly down the waste openning and the water all went down quickly. No clog there. I reinstalled the toilet and the same "slow" flush is still there.

I assumed I had a vent problem so I dragged a hose up to the vent exhaust on the roof and ran water into the vent for 5 minutes (3" vent pipe, 15' long). I assumed it would fill up if there was a clog in the vent would it overflow on the roof but the water drained down the pipe fine. I even snaked the hose down the vent for its entire length and the water ran through fine. But I still have the "slow" flush.

I should add that if I fill the kitchen sink and drain it, the water in the toilet bowl goes "lap, lap, lap...".

I'm still thinking this is a vent problem but at this point I don't know how to proceed.

Any ideas on what to do next?

Thanks in advance,
David in Missouri

Hi David,

You might have run the hose down the vent but you didn't snake it. You don't need a full blockage to stop the flush action. My advice would be to rent a power snake.
Drop the cable to the base of the lavatory vent and put out about 20' more.
Afterwards do the same thing to the kitchen roof vent. That one sounds like it might have a problem also. Good luck, Tom

Thanks, Tom. I'll try that tomorrow.

The vent in the bathroom is the only vent on the system (just a kitchen sink and toilet/tub/sink in the bath. Not much plumbing). The single vent probably adds to the problem.

"The vent in the bathroom is the only vent on the system (just a kitchen sink and toilet/tub/sink in the bath."

Unless the kitchen and bathroom's back to back and share a common vent then you should have two vents. Some times the plumber will do a "revent" in the attic and tie one vent back into another so that only one comes out the roof. If that's the case you'll have to cut into the vent and snake from the attic. Let me know, Tom

"Unless the kitchen and bathroom's back to back"

No such luck here. There is a single vent that runs from the bathroom through the roof. The kitchen sink just has a long run of drain. I guess that helps explain the "girgle" I had before I started in on this project. The builder of this "fine" cabin wasn't much of a plumber.

Looks like I've got a bit more work to do to complete this. Thanks for all of the help.