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Flapper for Toto THU138S

chat iconWHAT OUR CUSTOMERS SAY…

“Y'all are amazing. I live in Texas and it's faster to order express from Noel's than go to local parts stores. Customers can text Noel's a picture of the part they need and Noel's will find that part or the equivalent and text the link. They have 2-3 day shipping available. The staff answers the phone quickly, politely and they know their stuff! The unit I needed plumbing parts for was built in the 30s. No matter, Noels has me covered. I highly recommend them. Thank you Noel's for your efficient, old school excellence combined with current technology! You have saved me so much time, money, and aggravation! A++++++ ”
-Thalia,
07/03/2026

$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…

“Really great experience getting parts for my 30-year old frost free silcocks. They not only had the parts available, but they were shipped within a couple of hours. Great job, thank you! ”
-Phil R
02/08/2026