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Flapper for Toto THU138S

Bright red rubber toilet flapper with chain.

chat iconWHAT OUR CUSTOMERS SAY…

“The vacuum breaker on my outdoor spigot failed and Noel's Plumbing was the only placeI could find that had the appropriate mfr. part. I sent a text with photos on Wednesday evening to make sure the part I found was correct. In less than 2 hours later, I had a reply confirming it was the correct part. Placed my order that evening and received the part on Saturday afternoon (about 2.75 days) and my plumbing issue was resolved! I highly recommend - I really appreciated the prompt and pleasant response. ”
-Kimberly S.
04/25/2026

$14.87

 

The TOTO THU138S is a highly popular 3-inch toilet flapper designed specifically for TOTO’s G-Max flushing system. It controls the water release during a flush and prevents continuous leaks into the bowl.

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.

SKU: 15321 Category: Tags: ,

Stop your toilet from running and cut down on water waste with the TOTO THU138S 3-Inch Toilet Flapper Replacement.

 

THU138S

 

  • Fits popular tank models including the ST743S, ST744S, ST754SF, ST764S, ST774S, and several others.

 

Customer submitted image. 

 

Common questions about this product

Will this item replace the original OEM part? chevron-icon

Yes, this aftermarket part will replace your OEM part. 

Is this the correct item for my application? chevron-icon

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.

 

 

chat iconWHAT OUR CUSTOMERS SAY…

“Stop in Noel's , the counter man was very friendly, knowledgeable, and handled me the part I needed with in 2 minutes. I also got some professional advice. I will buy all of my plumbing needs here in the future. We home owners need business like this . ”
-Eric O.
02/29/2020
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