Toilet question

[Kurt Ullman]

One of the toilets in my kids home is emptying itself. Sounds like autosyphoning because of a blocked stack. HOWEVER, one of the websites suggested "power" flushing with hot water as a possible treatment. Figured I had nothing to lose but a couple gallons of hot water if it didn't worked so I tried it. About half a gallon in, the water apparently hit a certain height and the toilet flushed itself. I am guessing due to the weight of the water triggering the flush. So, does this change the diagnosis and possibly the treatment. Hers is a two story house and I have vertigo so climbing up on the roof really isn't an option.

[Bob_Villa]

Sewer or septic?

[trader_4]

I agree with your suspicion that it's a venting problem. I don't see how a blockage could cause the toilet to later drain itself. Also, never heard about the hot water fix either.

[thekmanrocks]

Repeated hot water might melt the wax ring sealing the toilet to the floor.

[David L. Martel]

Kurt,

Toilets aren't designed for hot water. Pouring a large amount of hot water may cause the bowl to crack due to thermal shock. Glad this didn't happen. Do your kids have vertigo? Someone needs to snake out the vent stack.

Dave M.

[Stormin Mormon]

From what you describe, "someone" will end up on the roof, with a drain snake, or garden hose and blaster tip.

[nestork]

Kurt Ullman:

Is this a basement toilet that was installed after the house was built?

If so, then it's not a venting issue at all. It's because the main drain line from the house is partially clogged. When was the last time you had that drain line cleared with a plumbing snake?

If it's a basement toilet that was added after the house was built, there's no requirement to install a vent stack for that toilet. All that's required is that the toilet's drain pipe be connected to the main drain line from the house to the sewer line or septic tank. In that case, if that main drain line is partially clogged, then that drain line can fill with water during a flush. As the water then drains away past the partially clogged section, the suction created behind the draining water can suck the water out of the toilet bowl.

If you can't remember when the last time the main drain line from the house was cleared with a snake or jetter, then I'd do that before you do anything else.