A standard toilet has two main ceramic parts: the bowl and the tank. The tank sits on top of the bowl and acts as a water reservoir, holding a specific amount of water ready for the next flush. The bowl is what contains waste and connects to the drainpipe.

The magic of the flush happens when water moves quickly from the tank to the bowl. This rapid transfer is what creates the force needed to clear the bowl and send its contents down the drain.

Inside the tank, three main components work together to start the flush: the handle, the lift chain (or rod), and the flapper.

The flush handle is a simple lever. When you push it, an arm inside the tank pivots upwards. This arm is connected to a small chain.

The lift chain connects the handle's arm to the flapper.

The flapper is a rubber or plastic seal that covers the flush valve opening at the bottom of the tank. This opening is the gateway for water to flow from the tank into the bowl. The flapper's job is to keep that gateway sealed until you press the handle.

When you push the handle, the arm lifts the chain, which pulls up the flapper. With the seal broken, the entire volume of water in the tank rushes down through the flush valve and into the bowl. This sudden surge of water pushes the contents of the bowl into the drainpipe.

As the water level in the tank drops, the flapper, which is designed to be buoyant for a few seconds, eventually falls back into place, resealing the flush valve. At the same time, another crucial part gets to work: the fill valve.

The fill valve, or ballcock, is a mechanism that detects the water level in the tank. It has a float that drops as the water empties. This drop opens the fill valve, allowing fresh water from the supply line to start refilling the tank. As the tank fills, the float rises. Once the water reaches the preset level, the float is high enough to shut off the valve.

A small tube, called the refill tube, also directs a bit of water from the fill valve down into the bowl via the overflow pipe. This ensures the bowl has the right amount of standing water to seal the drain and prevent sewer gases from entering the room.

Once the tank is full and the fill valve is closed, the toilet is quiet and ready for its next use. This entire cycle, from flush to refill, is powered by gravity and a few simple mechanical parts.

That's the basic process. Understanding how these parts work together is the first step to figuring out what's happening when your toilet doesn't flush correctly.