That would be your flush valve in the tank
Clogged drain or toilet. Also check the vent holes under the rim and clean the out.
is is most certainly a blockage in the sewer line. Call a plumber to come and check it out and clean your sewer line for you.
The toilet is the lowest point, fluids seeks the lowest level, other sewage is coming up through your basement toilet. The system might be installed wrong or there is a blockage in some discharge pipes. Call a plumber, it can be really bad, when I was a kid we had our whole basement flooded with two feet of raw sewage after a big rain storm.
Check to see if the tank is full... if it is check why the pump is not emptying it. If it is empty then there is probably a clogged or missing vent.
Dynamic stacks do not need to check for overflow, per se, because they will automatically allocate extra storage if it is needed. However, it is still necessary to check for the out-of-memory condition, so the truth is that dynamic stacks do need to check for overflow, so to speak, because out-of-memory is similar in consequences to overflow.
so as to check the overflow
This is not a venting problem. You have a possible blockage. Get a plumber to check your sewer lines. They may need to be cleaned out.
An overflow occurs when you attempt a mathematical operation that results in a number that cannot be stored in the variable type you are using. C# projects only check for overflows if you have explicitly configured the project to do so (because it slighly slows down your application). To do this, you have to go into the Project Properties page, Build tab, click Advanced, and then choose "Check for arithmetic overflow/underflow" If you set this option, then this code, which attempts to add 1 to a integer that is already at the maximum value that the 32-bit integer type can hold, would cause an overflow: int a = int.MaxValue; a++;
Sounds like the rubber line on the bottom of reservoir is leaking or tank is cracked CHECK IT OUT.
check that the toilet stopper has been switched on and check that the strainer inside the toilet inlet is clear of debris
Either the toilet is plugged or the sewer line under the toilet is plugged. At this point I would suggest calling in an expert (plumber) to determine the problem. You have not given enough information to say. Sounds like you do not have enough water pressure coming in to wash the waste away. Check out the holes under the lip of the toilet seat to see if they are blocked, causing you to get an inefficient flush. Our new toilet is much better at flushing with lesser amounts of water.
This could be an old floor drain. Check to see if you have another floor drain in a different part of the basement. ...It's not a drain. That is a rough-in or prepared area to install a bathtub or shower. It is normanlly a squared off hole near some other PVC pipe stubs sticking up for toilet and sink connections.