The first cause of low-level water in the toilet bowl is a faulty fill valve, whether it has been damaged or merely positioned poorly. The fill valve is supposed to control the amount of water that flows into the tank once the toilet has been flushed.
These fill valves usually rust as time goes on because they are generally made from cast brass. Because of this, the metal arm of the valve will get stuck, which causes the floating ball to go stagnant.
Solution: Fill Valves With A Stuck Metal Diaphragm
To fix this issue, you will need to clean the rust and then adjust the fill valve as mentioned above. It is also a good idea to change the fill valves from brass to PVC because these will be rust-resistant and durable.
Sometimes, you may find that there is low-level water in your toilet bowl because there is actually a crack in the bowl that causes water to leak out. Cracks can form anywhere in the toilet bowl, from the back, sides, or base. It is often the case that these cracks are very difficult to find, and this is going to be even more true if they are small, inaccessible, or hidden.
Because various people sit on the toilet bowl a day, the toilet bowl actually handles a lot of weight. So, if there is a crack, it shows that the bowl is coming to the end of its life and it is better to replace it than to try and fix it.
However, this may prove to be a very expensive solution, particularly if your toilet is a one-piece. So, you may be glad to hear that there might be another solution, particularly if it is only a small crack.
The fill tube, also known as a refill tube, is a small plastic hose in the toilet tank that links the tank and the tube together. It is supposed to control how much water flows through the tube and into the bowl every time the chain is flushed. However, when it does not work properly, it results in there being too much or too little water in the bowl.
The best thing to do if you suspect you have a damaged fill tube is to open the tank and inspect it to make sure it is clipped onto the overflow tube correctly. You should also check for damage at this stage. If you see that the fill tube is worn down, then, unfortunately, you will not be able to fix it. It will need to be replaced as soon as possible.