Toilet not filling fully and smell of sewer - Kohler Cimarron 2-PC Elongated Toilet with EcoSmart Technology, Left-Hand T...

Probable situation,
No working sewer vent pipe
While tank fills, a tube from float valve should drain not on tank but on top of large tube, large tube drains to the toilet to raise toilet water level.

The smell is sewer gas coming back in the house from the sewer or septic tank ether from a dried out water trap in a floor or fixture drain, or from the roof vent, or a hole or separation in pipe or fitting. Like wax ring under toilet. First pore water down every drain to fill any trap that might have gone dry, then flush toilet or run washer or drain bath tub.This will displace gas in pipe and will cause the smell to increases if there is no smell then the problem is fixed if not check roof vent it may need a charcoal filter on top, There is no water trap on air vent on roof and is an open hole to the sewer or septic, The heating system in the winter or AC in summer will draw the gas inside from the vent.If it is the vent you should be able to smell it from outside. If all tests fails You will need to have a smoke test done. A smoker is set up outside and the line is filled with smoke and will show where gas is coming from. Also it might be a good ideal to check all gas fittings in case it is a gas leak.

Ensure all your additional rough in plumbing is capped, and toilets or sinks that are not used for long periods of time , sometimes p traps may dry up allowing sewer gasses to enter the home so use them once in a while or fill with water once in a while ,same with floor drains. If that isn't it check that you have them installed.

are there any floor drains in the room and an unused bathtub or shower? if so the water may have evaporated from the trap and allow the sewer gas smell. try pouring water into all the drains and see if it is still happening. more elaborate problem may be a broken vent stack in a wall.

Suppose you plugged the drain of the sink and filled the basin with water, then removed the plug. I must think that only after the basin empties you would get the sewer smell, and the smell would persist until you slowly ran some more water. If you try this, and this is the result, then the problem is that the sewer vent (that is supposed to prevent the water in the trap under the sink from being sucked down the drain) is not working right. If this is a new problem then you may be able to clear what is probably a blocked vent pipe. If this bathroom has always had this problem, then you have a poorly designed or executed vent pipe setup that you can only fix it with some surgery to your plumbing. However, to clean the vent you can try pouring a good bit of drain cleaner down the vent pipe on the roof, followed by water. But because there may be several vent pipes sharing the same vent stack out the roof, the drain cleaner may not get to your blockage and may simply go down a different path. Good luck.

Sounds like you have an intermittently blocked vent pipe (the one that goes out through your roof). If there is gas pressure in the downstream sewer line and it can't get up through the vent, it could bubble up through your toilet or sinks. I would get up on the roof with a few jugs of powerful drain cleaner and dump them into your vents. You might also run a few dozen gallons of water down those vents after the drain cleaner has had time to work.
Good luck!

Smells usually come from the tank and not the bowl.
Buy tank deodorizer from local store located near toilet brushes.
http://secure.willert.com/images/bf_wire.jpg
Deodorizer hangs inside tank. make sure it reaches the water.

You can also drain and clean the tank using CLR calcium lime and rust remover.
The CLR and gunk are fine for flushing away as long as the gunk doesn't clog the flush holes that let water flow into bowl.
http://www.fixya.com/support/r6633961-toilet_doesnt_flush_water_just_spins

Sewer line can also cause of odor.
If the toilet bowl is not full of water, or if nearby drain is not filled with water, or if toilet is not sealed tight against floor, or if toilet appears to have dampness visible around base, or if a vent pipe terminates behind a wall instead of on the roof: these things can cause sewer air to enter room.

The smell may be coming from the sink trap if there is a problem with the vent pipe (that's in the wall from the sewer line to the roof). Do you ever hear gurgling in the sink drain when you flush? When you have the smell again, stick your head in the sink and see if that's where it's coming from. If you have a floor drain, the smell may be coming from there. In either case, a bit of water added to the drain will fill the trap and stop the smell. Please vote if you found this helpful. Good luck, Al K

jajoy,

Did you connect the sanitary pipe stack to the sewer line that takes away the flushed effluent? Check to see that the pipe is connected, not leaking sewer gas, not plugged up with an animal carcass, and that the pipe extends through your roof three feet past the roof line (keeps smell out of house).

The wax ring would only help if the toilet wasn't sealed to the drain. Is the odor coming up through the toilet? If so then your water level must be low in the bowl, allowing the trap to be open to air. Make sure the little hose from the fill valve is dumping into the overflow. This helps make sure the toilet stays full, when refilling.