1/8" per foot (1% grade)
5 inches of drop. 1/8 inch per foot.
Sounds like the trap in the sink is getting the water pulled out of it. It probably wasn't vented properly.
Your home improvement warehouse store or bathroom contractor should have "flush-up" toilet kits (sewage ejector pump, Qwik Jon is one I have installed. These are very handy where no sewer is available for standard toilet installation. The kit consists mainly of a tank and pump that will carry waste to the existing sewer lines and misc. parts and installation instructions. You provide the toilet and PVC from tank to sewer. They run about $800-$1000 depending on your needs (toilet only, or toilet, lav, & shower configuration). These require a GFCI outlet nearby so you may need an electrician, the rest is very easy. Good luck. In addition to the installation instructions I would recommend installing a "clean-out" in your PVC, especially if you are pumping a considerable distance, in case a clog develops.
If the existing sewer line is lower than basement grade (does it go into the basement floor and out of the house?) you can just connect in to the existing drain. By code, sewer lines must have a slope of 1/4 inch per running foot, meaning that raw sewage will run AWAY from the main plumbing stack of the house. If the sewer line is ABOVE the level of the basement plumbing fixtures, you will need to purchase and install a pump check-valve, and tank to install any plumbing below the house sewer line. If you have any questions, contact a licensed plumber to find out the needs of your home.
The man who invented the toilet--John Harrington--was an English nobleman. The infamous Thomas Crapper didn't invent the toilet, but he DID invent, among other plumbing products, the drain trap--a more important product than the toilet, as it made plumbing safe to have in your home. The trap keeps poisonous sewer gas from entering your house.
To vent off odors emanating from the septic/sewer system and to allow the toilet to flush correctly and the other drains to empty correctly.
You are to heavy to use the toilet.You must lose at least twenty pounds before using that toilet again. another way is to pay at least 12,000 at most 342,000 to fix your whole plumbing system and rip out your floors to fix the pipes.
some people flush their fish down the toilet when it dies, and the toilet is connected to the sewer.
You must be able to do various plumbing-related tasks, including but not limited to: repairing or replacing broken water pipes / sewer pipes, installing complete plumbing for new structures, clearing clogs from drain pipes, installing toilets, sinks, bathtubs, and other water-related appliances.
It is quite possible that your main pipe to the city sewer system has become blocked somewhere between the basement floor drain and the man city sewer line. Could be a result of items flushed down the toilet(s), or damaged pipes as a result of age, tree roots searching for water, etc. Suggest having your main access to the city sewer system checked by camera.
A trap doesn't cause the blockage. Something IN sewer line causes a blockage.
the toilet overflows if either the building sewer, branch line in your sewer system or trap in your toilet gets clogged.