How Does A Toilet Work?

How A Toilet WorksIt’s amazing how we take things for granted these days and simply use them and then go about our business without another thought. Take, for example, a toilet! A toilet isn’t really a complex piece of technology at all, but the simple mechanics of what is going on behind the scenes when we push that little lever on the tank, which in turn washes away the waste inside the bowl, within seconds, is a marvel.

So how does a toilet work?

A toilet is composed of two main pieces – the tank and the bowl. The working parts of a toilet are contained in the water reservoir called the tank, the large box shaped object that sits behind and just above the toilet. The part you sit on is called the bowl.

Inside and on the outside of the tank you will find multiple components:

  • The lid – allowing you to lift it off to see inside the body of the tank
  • The flush lever – this is found on the outside of the tank as you face it, and usually to the upper left. When you look inside the tank you will that the part of the flush lever that you don’t normally see (because that is inside the wall of the tank) has a chain connected to it, and when followed to the end of the chain you will see it is connected to the flush valve
  • The fill valve – this is inside the tank and connected to a long tube that connects to the main external water supply, that fills the tank with water
  • The float (also known as a ballcock– this looks like a pretty large tennis ball that is connected to a rod, which in turn connects to the fill valve
  • The flush valve (also known as the flapper) – this is a large flap that lays on the bottom of the tank and opens to allow the contained water in the tank to escape down into the bowl, and then closes to allow the tank to refill. The flapper and the flush lever are connected by a chain.
  • The overflow tube – this is a long tube that rises from the bottom of the tank, the head of which should just be over the water level of the tank when it is full

So here’s how it works! When you’re ready to empty the contents of the toilet, by pushing down the flush lever, you are setting off a series of events. The downward action of the flush lever will in-turn pull on the connect chain. The pulling of the chain will then pull on the flush valve and expose a large hole at the bottom of the tank, which then allows the water to escape, very quickly, out of the tank and down into the bowl.

As the water level falls the float, which sits on top of the water, also starts to drop inside the tank. The connected rod will then open up the fill valve and allow water to be pulled back into the tank to refill it. So at this point, water is leaving the tank and also coming into it too. It’s important to remember that the water leaving the tank is doing so at a much faster rate.

When the water inside the tank is almost empty the flush valve will close and seal up the discharge hole at the bottom of the tank, and the tank will continue to fill up. Once the water is back to it’s original full level and the float is in it’s normal position, it will then close the fill valve to stop more water from entering the tank.

So this is a very simplistic overview of how a toilet works. But there is one component, the overflow tube, that we have discussed its use! The overflow tube is simply a safety feature, in case either the fill valve or flush valve malfunctions. If either of these stop working, or don’t work properly, it could then cause the water levels in the tank to rise much higher than they should. Without the overflow tube, the water would flow from the top of the tank onto the bathroom floor. If the water goes past the normal level it will simply pour into the overflow tube, which is connects directly to the toilet bowl. So that overflow would escape into the bowl, rather than on your floor.

The most common problems for malfunctioning toilets usually lie with fill and/or flush valves that don’t work as they should. These are very inexpensive to buy, and are  fairly simple to replace. However, if this isn’t a task that you feel comfortable in taking on yourself, you should contact your local, licensed Charlotte NC plumbing contractor to get them to do this for you!


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