I have a toilet main line going to my septic tank. My basement sump pump is connected to the same main line that the toilet is connected. My wash machine drains into the sump pit. When my sump pump starts pumping water into the main line, the toilet gives a gurgle and the water in the toilet goes down.When I flush the toilet after the water goes down, it bubbles and fills back up. It then works fine. The only time I have a problem with the toilet losing water is when the sump pump starts up. Is this a clogged air vent problem or a partially clogged sewer line?

I would personally check your septic tank first to make sure it isn't full. If it needs pumped, every flush is pushing sludge into your lateral field and causing a lot of damage. Unless you have a tree between the house and septic, it usually isn't a root blockage; getting the tank pumped will effectively pull the stopper out of the end of the pipe and a paper blockage can sometimes slide out into the tank. Tank first, then main line.

I just had my tank pumped last month. I have it pumped yearly. Are you thinking a blocked
sewer line and not a venting problem? Also, I have another toilet and sinks in the house that seem to work ok.



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Yes, you have a substantial blockage somewhere in the main past the affected toilet and sump pump. If the other bathroom runs to the same line, it is most likely somewhere between where the first toilet is, and where the main line runs connect.

Thanks for the information and advice. I'll have that checked out.



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It could be neither. It is possibly a problem with how, and where, the pump is connected to the system. I had a customer who had the same problem, but there was no cheap or easy solution to cure it.

IF it were a blockage, the water would OVERFLOW the toilet, not suck the water out of it.

The sump pump system that I have worked well for many years, nothing has changed. I don't have any overflow from the sump pit or the toilet. The main pipe connected to the sump pump and the toilet has its own roof vent pipe. It does not have any kind of cover on it. I was reading some other sites that suggested that the symptoms I have could be a restriction in the pipe or a partially clogged sewage pipe. Plumbing is not one of my strong points so I'm trying to get some input from the experts out there. I really appreciate all the comments.