Our commode doesn't flush well and when it does it gurgles. Then all the water in the bowl empties. I told my husband that I thought the vent was plugged. He says that doesn't have anything to do with it. What could it be? And how can we fix it?
You are on the right track. A plugged vent can and will cause symptoms similar to what you are describing. I once found a birds nest over the top of a friends vent. It could be blocked from a ball or any foreign object. Many vent do use some bends in the pipe that a foreign object could stick in. Most of the time I have found either an improperly installed or a drain pipe that has sagged from insufficient pipe hangers. If the water is allowed to puddle in the pipe enough to cause an air lock (this is formed from the block in the pipe and the trap in the toilette then the water level has to fill in the bowl enough to overcome the weight of the water locked in the pipe. Then once flowing the block pulls the water threw causing a partial suction emptying the bowl. Drain pipes should ALWAYS have a pitch down. Sometimes a system might work normally and only a partial blockage (slow drain) can bring it to this state. If all else looks well many times plumbers can do a main drain rodding threw a roof vent but I would rule out everything else first. Many time a clean main drain line can have even a improerly set up drain sytem work fine. but if it starts to hold water many thing can happen. I have seen homes build without vents! not all areas had codes enforced st sll times. Water out is all they though of. Some of these system can work ok. but they canot have any water build up in the pipes causeing any airlocks.