How To Choose A Toilet Flapper?

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A constantly running toilet is not only annoying on the ears (and costly when it comes to your water bills), but it could also be a sign that it’s time to replace your toilet flapper.

The toilet flapper is a valve that seals water into the tank until you flush. You probably don’t think about your toilet flapper until you really need to, and then you realize that there are a few different types on the market.

With so many toilet flappers out there, how do you know which one is the right one for your toilet?

The most important thing is to get a toilet flapper that is the right size. Flappers vary in size from two-inch to four-inch diameters and you have to get the right one to ensure the best fit for your toilet.

The Fluidmaster 502P21 toilet flapper will fit a 2-inch flush valve and you can order it from Amazon (Affiliate Link)

The Fluidmaster 5403 toilet flapper has an adjustable solid frame and fits 3-inch flush valves. You can easily find it at Amazon (Affiliate Link)

While size is the most important factor to choosing your toilet flapper, there are a few other variations that could affect your choice, such as shape and seal type.

Here is your guide to choosing a toilet flapper, including how to measure a toilet flapper, and putting runny toilets to an end once and for all.

How Do I Choose The Right Size Toilet Flapper?

During the 20th century, toilet flappers used to be universal. Every toilet manufactured in the United States had the same size valve opening, making the job of replacing a toilet flapper much easier.

Over the past few decades, manufacturers changed the way toilets flush, which means that certain toilets use wider valves and toilet flappers than others.

Even though it adds an extra step to your process, you have to make sure that you are buying the right size toilet flapper. If you don’t replace your existing toilet flapper with one that’s the right size, the flapper won’t fit on the valve properly and will allow water to leak around the seal, impacting the working of your toilet.

A good rule of thumb is that older toilets made before 2005 usually have smaller, two-inch water valves. Toilets made after 2005 usually have bigger, three-inch water valves. (Link)

The reason why water valve size varies now is the introduction of WaterSense toilets that use less water when they flush. The larger valve (and flapper) allows more water to rush in at once, creating a more powerful flush while using less water over time.

If you are looking for a Watersense toilet and have a compact bathroom, we recommend the DeerValley Compact One-Piece Toilet (Affiliate Link)

However, since precise fitting is so important for toilet flappers, guessing based on the year your toilet was manufactured won’t lead you to the right flapper.

The best way to choose the right size toilet flapper for your tank is to measure your existing one.

How To Measure A Toilet Flapper?

Even if you don’t have that much experience with home renovations, measuring a toilet flapper is not that difficult. All you need is a measuring tape and access to your toilet’s water line.

Here are the steps you need to take to measure your toilet flapper:

  • Turn off your water line. You don’t want to accidentally flood the tank while you’ve got your hands in there!
  • Lift the lid of the tank and locate your toilet flapper.
  • Decide if you’re going to measure the flapper while it’s still on or off the toilet. Measuring the flapper without removing it is a bit harder as you have to measure the flapper from the side to avoid the dome, however it saves you the trouble of removing the entire mechanism.

    If you decide to remove the flapper:

  • Disconnect the flapper chain and unhook the flapper ears from the pegs in the tank to remove it.
  • Place your measuring tape over the flush valve opening and measure the diameter. The nearest inch will be the size flapper you need to buy.
  • Replace your flapper and turn the water back on.

    If you don’t remove the flapper:

  • Press and hold the flushing mechanism.
  • While the flapper is still attached to the valve, measure the width by bringing your measuring tape as close to the opening as possible.
  • Turn the water back on.

What If You Don’t Have A Measuring Tape?

If you don’t have a measuring tape at home but still know that you need to replace your toilet flapper, don’t worry! You have a few options for making sure you’re getting the right size toilet flapper.

  • Estimate by water consumption. If you know how much water your toilet uses when it flushes, you can estimate the size of your toilet flapper. If your toilet uses 1.28 gallons per flush, you probably have a three-inch valve, and if it uses as much as 3.5 gallons per flush you probably have a two-inch valve.
  • Compare the size to a household object. If you don’t have a measuring tape on hand but don’t mind getting your hands dirty, use a household object to compare to your toilet flapper. If the diameter is about as wide as an orange or baseball, then you’re looking at a two-inch flapper. If it’s as large as a softball or grapefruit, then it’s a three-inch flapper or more. This video illustration by Korky may help. (Link)
  • Take it with you. If all else fails, just remove your toilet flapper and take it with you to the hardware store. The staff there can match a new one that will fit the same (the only downside is that whoever is left at home can’t flush the toilet while the flapper is gone).

How Many Types Of Toilet Flappers Are There?

Besides variations in terms of size, there are a few other variations in terms of shape and material that you’ll encounter when shopping around for a toilet flapper.

Here are some terms to know:

Seat Disk Toilet Flapper

A seat disk toilet flapper is most common in older toilets. True to its name, this flapper is shaped like a small disk. It has a larger tube attached to the disk, usually made of plastic, that flips over when you flush the toilet. The reason why most newer toilets don’t use seat disk toilet flappers is because this mechanism takes up lots of space in your tank and is easily damaged. If you are looking for a seat disk flapper, you can find one at Amazon (Affiliate Link)

Tank Ball Flapper

This is another type of toilet flapper that is very self-explanatory. Instead of a rubber cap, this mechanism uses a rubber ball to block the valve. When you flush, a chain attached to the ball lifts it and allows water to pass through. Tank ball flappers are also less common in newer toilets because they get damaged easily and replacing them is difficult thanks to the complexity of finding and attaching the right length of chain.

Rubber Flapper

This is the type of flapper that you probably have in your toilet, especially if you’ve replaced your toilet since 2005. The rubber flapper is a small, cone-shaped flapper made out of rubber that goes over the valve. It has no moving parts that can break and seals easily around the opening of the valve. Its chain can also break, just like the tank ball flapper, but these flappers tend to be more durable. If you are looking to replace your rubber flapper, we recommend the Fluidmaster (Affiliate Link)

Canister-Style Flush Valve

Some toilets don’t use toilet flappers at all, instead, they have a column-shaped mechanism called a flush valve. These are more common in newer Kohler or American Standard toilets.

If you have this type of flush mechanism, then information on replacing a flapper won’t be helpful for you. To replace a canister flush valve or the valve seal, have a look at this video from Kohler (Link) 

Related Questions

Here are a few other questions you might have about your toilet flapper.

Do Toilet Flappers Fit All Toilets?

When you go to the hardware store, you’ll find some toilet flappers that claim to be universal. However, this doesn’t mean that toilet flappers fit all toilets.

As mentioned above, you have to get the right sizing for your toilet valve. Instead, the “universal” label means that the toilet flapper will fit all toilets with that size valve, not just valves from a specific manufacturer.

This is helpful because universal flappers are usually more affordable than manufacturer-specific flappers.

When Is It Time To Replace A Toilet Flapper?

There are a few signs that it’s time to get a new toilet flapper. If you constantly hear your toilet running, that’s a sign that your flapper is not properly sealing the valve between the tank and the bowl anymore.

To test if it’s working, place a drop of food coloring in the tank and don’t flush the toilet. If within 30 seconds the colored water leaks into the bowl, that means the material in the flapper degraded.

Even the best flapper starts breaking a bit after 5 to 10 years, so having to replace it is normal.

The Final Word On Toilet Flappers

Once you know which toilet flapper type that you need, choosing the right one is easy.

Most toilets use a modern rubber toilet flapper, but before buying one, double-check that you are not using an older seat disk mechanism or a canister-style valve.

Finally, make sure you measure your old toilet flapper to ensure you’re getting the right size when replacing it.