One of man’s greatest and most useful inventions is the humble toilet. It has allowed us to modernize the old ways by bringing the old outdoor privy into the house minus all the drawbacks of an outhouse. There are basically six major components to a toilet as well as a mechanism called the siphon action. Knowing how your toilet works will not only help you to appreciate it, but it will also help guide you when there’s a problem with it.
These six major parts are the toilet bowl, the toilet tank, the toilet fill valve, the toilet flush valve, the float, the overflow tube and lastly, the handle.
The toilet bowl is especially designed to hold water in its base. It also has the ability to take in water from the tank via the rim and a siphon jet hole situated at the base of the toilet bowl. Finally, found at the heart of the toilet is the siphon tube. The siphon tube is a tube shaped unit that is integrated into the back of the porcelain toilet bowl and serves two main purposes. First, it acts as a trap so that no sewage gasses can leak up into the home. The second is the more important purpose of the siphon tube. It acts as the mechanism for drawing water and waste products out of the toilet bowl base.
The siphon tube is quite an interesting contraption. If you’ll try to notice, even when you repeatedly pour individual cups of water into the toilet tank, the water level does not rise. If you try pouring a whole bucket of water into the toilet bowl really fast, you will see that the water level in the bowl will initially rise but will then be drawn down very dramatically and up to a point where there is practically no water left in the toilet bowl. This happens because of the siphon action. When you pour a large volume of water into the toilet bowl it causes the water in the siphon tube to rise and spill over into the sewage pipe and then because of the principles of a siphon, the water is automatically drained very quickly from the toilet bowl and into the sewage pipe.
The toilet tank is the one responsible for holding the water supply required for the flushing action. Once you push the toilet handle down, a rubber flapper installed inside the tank is lifted and allows the water to rapidly pour into the toilet bowl. As soon as the water pours into the toilet bowl, the siphon effect instantly occurs which causes the toilet to flush and empty the waste from the bowl. The toilet bowl is designed to have the water flow from the rim and one large hole at the base of the toilet bowl into the toilet. This design basically creates a swirling function to assist in flushing the waste from the toilet. Once this is over, the flapper gets back into position and the water in the tank starts to fill up again and will only stop when the float reaches its predetermined height.
The next time you use your toilet bowl, appreciate the little things that work together to make your life more convenient and healthy.
{ 10 comments… read them below or add one }
can i only use integrated overflow flush mechanism with a close coupled toilet, or can i use them with a typical flush pipe system?
@Darren Jones A flush valve is for use with close coupled or one piece water closets. Flush pipe systems usually use a vacuum breaker and diaphragm to regulate the water level.
From time to time, I experience the siphon effect described in your 2nd para. with my elderly single flush toilet. However, afterwards, some water seeps from the base of the toilet across the floor.
The evacuation pipe is vertical below the toilet, going through the floor via the basement, an initial drop of about 1 metre.
I wonder if changing the toilet to horizontal evacuation through the exterior wall to connect to the soil pipe, together with a sewer vent pipe would be a solution. Being on French main drain, the first inspection chamber is some 20 metres away, hence the possible need for a vent to allow air to escape.
Your views please.
Note: the toilet is single flush.
@Terry Hawker Yes, adding a vent and draining horizontally would be ideal. It also sounds like the siphoning has “blown” your wax seal under the toilet which will have to be replaced.
Question: Toilet will not flush without using plunger. When I use plunger it drains. Do I need a new toilet. I read on your site that the siphon action is what flushes the toilet.
when i flush toilet, noise from pipes very loud and have to turn on cold water tap to stop the noise
I have a problem similar to Joan Wilson (8/20/2010). When the tank has refilled with water, there is a loud sharp humming noise. There are two toilets in the house, the upstairs is fine, this is the downstairs toilet. What’s wrong and how can I fix? Thanks.
Sewer smell in bathroom. Low toilet water or plugged vent pipe? Roof is not easy to walk on, because of tile. But think it could be plugged up vent.
When flushing toilet the flapper drops down too soon not allowing it to flush properly.
I am having an issue with my toilet in the basement, sometimes it flushes great but other times it just fills up and doesnt, but when I flush the main floor toilet It sucks out all the water in the basement toilet. there is no leakage anywhere. can you please help before I end up getting a flooded basement ..
thanks