Gerber G0099788 3" Flapper for HET Tanks

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Bright blue soft rubber flapper with beaded chain and metal clip.

WHAT OUR CUSTOMERS SAY…

“I sent in photos of a broken cartridge (still installed, couldn’t take it out myself due to water shut-off restrictions in a condo) and even with the limited view they were able to tell me the exact part I needed so I could have it ready for the plumber (meaning I didn’t need to pay for a plumber to come out twice!!) ”

-Alaina W.

06/27/2026

$14.27

The Gerber G0099788 & 99-788 is a genuine 3-inch soft toilet flapper designed for high-efficiency toilets (HET).

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The Gerber G0099778 3-Inch Toilet Tank Flapper is a genuine blue rubber replacement part designed to stop toilet leaks, restore flush power, and save water. It is a prime example of a straightforward, tool-free DIY plumbing project that any homeowner can complete.

G0099778 99-778

3-inch diameter (measures approximately 3 and 5/8 inches across the top)
Soft rubber/plastic construction; lacks the extra underside hole found on the Gerber 99-770 model
Fits select 1.28 GPF (gallons per flush) high-efficiency models
Gerber Viper tanks and toilets (such as Gtb20528, Gtb20552, Gtb20562, Gws28590, Gvp28590)
Gerber Maxwell tanks (such as G0028970 and G0028980)