For those without a pet who might use the toilet as the occasional drinking fountain, missing water from a toilet bowl is evidence that there is a repair issue which must be addressed. This is especially true if you have a tank full of water waiting for the next flush.
You Have a Toilet Paper Problem
If water is not in the toilet bowl, but it is in the tank, then you likely have a partial clog in the trap which is caused by toilet paper. The toilet paper will siphon water out of the bowl, much like a lantern siphons oil from a reservoir to create fire.
To stop this issue, you will need to use a plumbing auger to dislodge the clog. Plunging may be able to remove it as well, but you’ll use less water in the removal process with an auger.
You Have a Structural Problem
If you don’t seem to have a toilet paper clog, then there is a good chance that the interior of the toilet has been damaged. When a crack occurs within the interior of the toilet, the water can drain out of the bowl. It may lead the water directly into the drain or it could be causing water to seep into your floor.
The only solution to fix this problem is a complete replacement of the toilet bowl.
You Have a Gravity Problem
Have you ever flushed a toilet using a bucket of water? By using the force of gravity, the extra water creates a flush without engaging the tank. Because the tank has not been used, there is no water to replenish what was in the bowl.
In some homes where a toilet is on an upper floor, there is a possibility that human waste can trigger enough extra weight within the toilet bowl to cause a flush to happen. If this occurs, just engage the tank so the bowl can be cleaned and the water replaced.
Water can drain from a toilet bowl for a number of reasons. By identifying the cause of the problem, you can then implement the correct solution.