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Plumbing in the Home/Toilet won't flush, but does after upstairs toilet is flushed.


We do have septic issues.  The downstairs toilet seems to give us the most trouble.  Frequently it overflows (will be putting brick in tank because that might be just enough to prevent so many overflows), but especially if the dishwasher or washing machine are running.  Typically, it doesn't flush, but over time it does drain to almost empty.

Tonight it would not flush.  It overflowed on the first flush.  No shower, washing machine or dishwasher ran tonight. It did not drain more than a couple inches.  Then the upstairs toilet was flushed and it bubbled I was worried it was going to overflow again, but it didn't.  Next thing I knew it had flushed.

Could this just be from a full septic or does it sound like a clog between the toilet and the septic?  Why did it flush after the upstairs toilet did.

Thank you.

Hi Peggy,
Sounds like there is a partial stoppage in the main line.  This stoppage may be causing a blockage of the vent line as well. Vent piping comes off the top of the drain lines.  If the pipes are full of waste, the vents get blocked.  Without a functioning vent, fixtures will not drain properly.

This whole drainage thing is dependent of flow.  Drain lines need to have a certain flow rate to "scour" the pipes.  When the flow rate drops, solids start to settle out and build up in the pipes, eventually creating blockages. If the septic is full, it may be contributing to this problem.

First, I would have the main drain properly cleaned by sewer auger or jetting. With a full septic, this might help and it might not, or not for long.  Ultimately, you will need to get the septic pumped.
Good Luck,

Plumbing in the Home

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Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


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