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…

“Love Noel's Plumbing Supply! They are one of my favorite oddball plumbing parts purveyors. As a professional plumber, I rely on sites like Noel's to keep antique and rare fixtures alive. My customers and I are so grateful! ”

-Danielle E.

03/25/2026

$14.27

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

We can ship anywhere the US Postal Service ships. For orders being shipped outside the US, please contact us at (888) ASK-NOEL, asknoel@noelsplumbingsupply.com, or via the text widget on this screen.

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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)

Common questions about this product

Yes, this is the OEM recommended part.

If you’re not sure text us a picture 1-888-275-6635 or email us a picture at noelsplumbingsupply@fuse.net.

We will make sure you have the right part.

WHAT OUR CUSTOMERS SAY…

“We were able to buy parts for our antique toilet here! Unfortunately, the toilet fell off the wall so we had to return the parts before we got the chance to use them. But returning was quick and easy! The staff is super helpful. ”

-Dori M.

09/23/2023