Why does the water level in my toilet rise and fall so that it doesnft flush well some days?
Itfs probably related to the stink (vent) pipe on your roof, which allows gases that build up in the sewer pipes to be carried away. A marked difference between the low pressure outside and the higher pressure inside will cause the water levels to fluctuate. It will be less pronounced if you leave the bathroom door open, which may not be desirable. You can also climb on the roof and check out the stink pipe, which may need to be cleaned out with a snake.