Our toilet sounds like water is always running, however, the water level in the tank does not decrease. What could be the problem?
You can try putting a drop or two of food coloring into the tank and wait 5 or 10 minutes and see if it shows up in the bowl. If it does, you may have a bad flapper or a cracked flush valve or even a hairline crack in the internal toilet trap. Running water in the area of your toilet is not uncommon so please do not panic. There are a number of quick and easy fixes you can employ to get the problem addressed. Before turning to the food coloring dye, try some visual evaluations of whether you can actually see the running of water and if it is coming from your toilet. You very first cue will be the sound of water running and if you hear that then pull off the toilet tank lid cover and take a peek. Often the flapper will be the cause of your issue. It may be obstructed by the attached chain that is attached to the toilet handle stem. Many flappers make use of a metallic chain instead of a plastic chain and those types of chains tend to get caught up under the flapper drain and prevent the toilet flapper from closing off fully to properly seal.
Sometimes the little water hose will come loose and as a result water will not properly be guided to the right place, causing the running noise you may hear. That is quite easy to fix as you only need to re-attach the hose. But back to the toilet flapper. These little devices are important, though not costly. When working properly, you never think of them as they function properly hundreds and hundreds of times without failure. But over time as they become worn, they can begin to fail. Sometimes the various elements within the tank can cause the edge of the flapper to stick and as a result not fall back down to close off and seal properly. When you suspect this as the kernel of the problem, you can do a scrubbing of the flapper and anything it can come into contact with to ensure a tight seal. Invariably, after time you will want to replace these flapper in your toilets so as to ensure their proper functioning. Since the toilet gets a lot of use, its best to replace them at least every year in all of your toilets in your home.
Fortunately, the problem you have reported is not serious and at worst, you may be only losing a few cents per day in water that is causing the running water noise you described. Nevertheless, it is not something you want to continue to occur because the cents add up and importantly, the need to ensure you get the proper water levels in your toilet tank to facilitate an adequate flush is critical.