No, a new toilet flapper won’t save you money — unless your current flapper has a leak or other issue

As of June 21, 2022, nearly a third of the U.S. is facing severe drought conditions or worse. Many state and local governments have responded to the dry conditions over the last couple of years by urging residents to reduce water use.

In a TikTok with nearly a million views, one mother said that her family saved up to $50 a month by replacing all of their home’s toilet flappers — the device that lets water into the toilet bowl when you flush. She said that because her new flapper closes quickly, it uses less water and thus saves money.

THE QUESTION

Can a new toilet flapper save you money by using less water per flush?

THE SOURCES

• New York City Department of Environmental Protection
• Santa Cruz Water Department
• Korky Toilet Repair
• Fluidmaster
• Stephanie Blazek, executive director of the Plumbing Heating Cooling Contractors of North Carolina

THE ANSWER

No, a new toilet flapper cannot save you money by using less water per flush; however, if your current toilet flapper is leaking, replacing it will save you money.

WHAT WE FOUND

The toilet flapper is the valve that seals the opening between the toilet’s tank and bowl. It’s a small disc that’s usually made of a combination of plastic and rubber. The water in the tank rushes down into the bowl when the toilet is flushed and the flapper opens. Once a certain amount of water is released into the bowl, the flapper closes again to let the tank refill.

It’s possible a person could save $50 a month by replacing the flapper in one or more toilets in their home, says Stephanie Blazek, executive director of the Plumbing Heating Cooling Contractors of North Carolina. But she said a person would only see these savings if they had a leak in their old flapper.

“A lot of times people have toilets where they have a leak around the flapper, and so they're consistently using water,” Blazek said. She explained that you can check for a leak by putting food dye in the toilet’s tank, waiting 20 minutes and then checking to see if there is color in the toilet bowl. 

“If you see the color, that means that you have some sort of leak in the flapper, and so you are consistently losing water,” Blazek continued. “If you don't see it, I wouldn't bother changing the flapper. I don't think it would make that much of a difference.”

According to a New York City Department of Environmental Protection pamphlet, a small leak can waste 30 gallons of water a day and cost 40 cents a day while a medium-sized leak can waste 250 gallons of water and cost $3.30 a day. That’s $12 to $99 in a 30 day period. The pamphlet says the flapper is the most likely cause of a toilet leak.

“A lot of people will have a leak and not even know it — they wait for the toilet to start running,” Blazek said. “You constantly hear that running toilet, and it's annoying, and so you change it. But you could have a leak far before then.”

The reason a leak in the toilet flapper can become so costly is because of how the toilet flushing mechanism works. Korky Toilet Repair, a company that sells toilet parts, says that another part in the toilet tank, the fill valve, brings water into the tank after the toilet is flushed and stays on until the tank is refilled. Any time water exits the tank, the valve turns on to refill the tank back to its proper level.

So if there is a leak in the flapper that allows water to escape the tank while the toilet is not in use, then the fill valve will make sure water is constantly flowing into the tank to replace the leaking water.

Each toilet is designed to flush with a certain amount of water, the Santa Cruz Water Department says. Toilets built before 1982 use five to seven gallons to flush. Toilets built between 1982 and 1993 typically use 3.5 gallons to flush. Toilets built after 1994 use 1.6 or fewer gallons of water to flush.

The Santa Cruz Water Department says all toilets should have a mark somewhere, often near the seat hinge, designating how much water they use per flush. A newer toilet will have a label that says 1.6 gpf (gallons per flush) or 6.0 lpf (liters per flush).

This is part of the reason why replacing the flapper is unlikely to make much of a difference unless there’s an issue with your current one. Most flappers are designed to shut the moment the tank has released the appropriate amount of water to flush that specific toilet.

Although there are adjustable toilet flappers that give you some control over how long the flapper stays open and how much water a single flush uses, there’s no guarantee you’ll be able to lower your water use per flush with them.

According to Fluidmaster, which makes toilet parts, adjustable flappers don’t automatically close based on the amount of water left in the tank, but instead, close independently through another mechanism. They are intended for toilets that use a flush volume of 1.28 and 1.6 gallons per flush, and should not be used in toilets made before 1994. That’s because modern toilets are designed to stop flushing before all of the water leaves the tank.

But because toilets are designed to work with certain flush volumes, there’s a chance your toilet may not flush properly if you set an adjustable flapper to close sooner and allow less water into the bowl than it normally would. Shortening the time the flapper remains open may give you a weak or incomplete flush, Fluidmaster says, requiring you to hold the handle down for a longer time.

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