Canister Flush Valve vs Flapper

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Last Updated on July 27, 2022 by acechapman

So, you want a toilet with maximum flushing power, but how do you achieve this? Well, one big thing to think about here is the canister flush valve vs. the flapper. Both have their merits, but only one comes out on top. Which one is it?

Criteria for the Best Flushing Toilet

Alright, so you are looking for a toilet that flushes really well? Yes, of course, there are hundreds of different toilets out there, but they don’t all perform in the same way. If you don’t get a toilet that flushes well, you will often end up dealing with clogs, which is no fun. So, now we want to go over the main criteria for the best flushing toilet, with one of the really important aspects having to do with the type of flush valve it comes with.

Canister Flush Valve vs Flapper

Perhaps one of the most important aspects to keep in mind in terms of the best flushing toilet is what the flush valve is like. Now, the flush valve is housed inside of the toilet tank, at the top where the water is. When you push the flush button or press the flush lever, this valve opens up and sends the water in the tank down into the bowl. It’s how a toilet flushes.

Now, the old and generally used style of the flush valve includes a flush valve flapper. This is more or less a simple rubber stopper attached to a chain. When you hit the flusher, this stopper gets lifted up and sends the water down into the bowl. This is a perfectly fine way to go, and it’s what most toilets still use today. It works more than well enough to flush pretty decent amounts of waste.

However, the new flush valve system includes a canister flush valve. This involves a tall and cylindrical canister that sits atop the valve. When you hit the flush button, the whole canister lifts up and allows water into the valve. This is a lot more efficient, as it allows a larger amount of water down into the valve at once, therefore increasing flushing power.

It’s important to note that unlike with a flapper, where one end stays on the valve, the whole canister lifts up, therefore allowing a lot more water into the valve than the flapper does. With that being said, canister flush valve systems are also more expensive than toilets that just have a simple flapper design.

Flush Valve Diameter

Canister Flush Valve vs. Flapper
The next thing you want to look for to get as strong a flush as possible is that you get a toilet with a flush valve that has a very large diameter. The larger the diameter of the flush valve in question, the more water can pass through at once, and the more water can pass through the valve at once, the stronger the force, thus allowing your toilet to flush down more waste at once.

Going back to this canister valve vs. flapper argument, generally speaking, the valve size for a canister flush valve is usually between 3 and 3.25 inches, whereas with a normal flapper system, the valve diameter is sometimes as small as 2 inches. Therefore, as you can see, a canister valve system helps to increase flushing power in more ways than one.

The Trap Way and Flush Type

Something else to note is that the size and shape of the trap way of the toilet can make a big difference when it comes to flushing power. Generally speaking, the larger the trap way is, the less likely the chances of a clog occurring. Now, this does also have to do with the type of flush a toilet has. If you have a gravity-fed toilet, it’s going to have a fairly wide and short trap way, which does not easily clog, but it also doesn’t do a great job at flushing a lot of solid waste at once.

On the other hand, there’s the siphonic jet flushing system, which has a much narrower and longer trap way. These trap ways are designed to produce a lot of force, which sucks waste down with a lot of power. However, due to the long and often wavy pathways which these traps feature, they do have an increased tendency to get clogged.

Dual Flush

Canister Flush Valve vs. Flapper
If you want to ensure that your toilet flushes well, but also so you don’t waste a ton of water, you might also want to invest in a toilet that features a dual-flush system. These flush systems come with 2 buttons, one which uses under 1 gallon of water per flush, which is for liquid waste, and a second button which uses roughly 1.6 gallons of water, for solid waste. This way, you can ensure that you always get the proper flush for the type of waste in the toilet bowl, without wasting water in the process.

The Rim

The other thing which you may want to look for is the rim of the toilet. Normal rims just have the water holes right under the rim, which is fine, but they can often leave streaks and residue inside of the bowl. It may not have much to do with the flush itself, but it can still add to your cleaning woes. On the other hand, if you get a bowl that has a rimless design, they tend to really swirl the water around the bowl, thus removing more residue.


The bottom line is that if you want a toilet with maximum flushing power, you will want one that features a canister flush valve as opposed to a flapper. It’s a much better option to go with. Also, keep in mind the other factors we discussed.

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1 thought on “Canister Flush Valve vs Flapper”

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