Treato found 16 discussions about Cold Symptoms and Cats Allergy on the web.
Best Answer: When the toilet is flushed, the toilet is robbing pressure from the shower, which is usually close to the toilet. As the COLD water pressure goes down from the toilet flush, the HOT water pressure is higher, therefore the water gets hotter as the COLD pressure goes down.
Your second floor toilet is often referred to as a phantom flusher. You think it has flushed because you here the toilet tank filling with water. No ghosts or goblins flushed the toilet. The ball cock valve in the tank turned itself on because the water level in the tank dropped.