Tip One: Make sure the water shut-off valve is turned on all the way on.
Occasionally, friction from a nearby object or a deep-cleaning session can nudge it to the off position, preventing water flow to the tank. This leaves just one or two flushes before the water level gets too low for the toilet to work properly.
Tip Two: It’s possible that you’re dealing with a clogged pipe.
Heavy paper products are usually the culprit here. To prevent another problem by switching to lower-ply toilet paper, and remember that flushing paper towels or feminine products are pretty much asking for trouble.
Tip Three: Still having trouble? Take the top of the toilet tank and check the flapper.
Carefully remove the top of the tank and set it aside for a moment so you can check if your flapper, which is located at the bottom of the tank and often red in color, is causing the backup. One that looks warped or damaged needs to be replaced.
Tip Four: Check that the lift chain is connected to the toilet handle and the flapper.
If your flapper shows no signs of a problem but there’s too much slack in the line, it won’t react properly when you try to flush.