There are several different reasons why your toilet may be continuously running, which can be narrowed down to a few common causes. Here are some reasons and ways to fix the running toilets, as per Rooter Hero. 1. Float is too high: According to Rooter Hero , the height of float in your toilet's cistern might be high, causing your toilet to keep running. This problem can be fixed with DIY, or you can hire higher professionals like Plumber Monrovia . The toilet's float, which may or may not look like a ball as in the cistern above, or an upturned cup in a newer Toilet which controls the water level in the cistern tank. The water leaves the tank as you flush, and the flair drops automatically. When the water refills, the float rises until it reaches the fill level, the level of fill level should always be below the overflow tube and fill valve of the toilet. If the water keeps running in the toilet, the float may be set too high and need adjusting downwards....