The wax ring is crucial to avoid leakage when using the toilet. The wax ring is exactly as its name says— it is a sticky wax ring that forms an air and watertight seal connecting the sewer pipe to the bottom of the toilet. These pieces are extremely sticky and gummy-like, helping then to seal out any air (or air bubbles) and to prevent and drops or streams of water from escaping during the water emptying cycle.
Wax rings can break quite easily, however. A loose toilet can cause the wax rings to slip or dry out, causing leaks. Another way to ruin a wax ring is when the main sewer line backs up into the toilet, as the standing water can cause erosion of the waxy seal. All toilets need wax rings, so it is vital to replace the wax ring whenever it begins to erode. The first clue that your wax ring needs to be replaced is any leaking water from the base of the toilet. Another sign is water marks on the floor (where water sat and dried up) or an unpleasant sewer smell, as the gasses escape through worn down wax seals.