TOTO THU500S Replacement Flapper 3 Inch
- Outlet Connection Size: 3 inches
- Inlet Connection Size: 3 inches
- Thread Size: 3 inches
- Valve Type: Toilet Flapper Valve
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
Go with this only after matching your existing flapper's part number against TOTO's compatibility list, since it's built for specific TOTO tanks rather than as a universal 3 inch part.
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ASIN: B076KL3K87Model: THU500SCategory: Toilet Flappers
Overview
A manufacturer replacement flapper for select TOTO 3 inch flush valve toilet tanks, sized to match a specific list of original TOTO flapper part numbers.
This is a compatibility part rather than a universal one: it's built to replace a named set of TOTO flapper numbers, including THU138S, THU175S and THU331S among others, instead of fitting flush valves broadly. Checking your tank's current flapper part number against that list matters more here than measuring the opening yourself.
- Genuine TOTO replacement part
- Replaces 12 named TOTO flapper numbers
- 3 inch sealing surface
- Polypropylene body with rubber seal
Who it's for
TOTO toilet owners whose tank uses one of the listed 3 inch flush valve flapper models. Not a fit for non-TOTO tanks or TOTO models outside the listed part numbers.
Pros and cons
- Manufacturer part matched to specific TOTO tanks
- 3 inch sealing surface
- Includes chain and TOTO-specific setup instructions
- Only fits the listed TOTO part numbers, not universal
- Not usable on non-TOTO tanks
Performance notes
The flapper pairs a polypropylene body with a rubber sealing surface across a 3 inch sealing area, matched to the flush mechanism used across the listed TOTO tank models. It ships with a chain and setup instructions specific to TOTO tank models rather than generic installation notes.
Specifications
| Brand | Toto® |
|---|---|
| Model | THU500S |
| Dimensions & fit | |
| Outlet Connection Size | 3 inches |
| Inlet Connection Size | 3 inches |
| Thread Size | 3 inches |
| Item Weight | 0.27 g |
| Size | 3 Inches |
| Item Dimensions | 4.8 × 3.5 × 2.5 inches |
| Construction & materials | |
| Material Type | Plastic |
| Exterior Finish | Plastic |
| Included components | |
| Number Of Pieces | 1 |
| Number Of Packs | 1 |
| Unit Count | 1 |
| Included Components | Flapper |
| Warranty & support | |
| Manufacturer Warranty Description | Manufacturer One Year Limited |
| Other details | |
| Valve Type | Toilet Flapper Valve |
| Outlet Connection Type | Standard 3-inch Connection |
| Inlet Connection Type | Rubber Flapper |
| Number Of Ports | 1 |
| Thread Type | Plastic |
| Number Of Items | 1 |
| Item Type Name | Replacement Flapper For Select TOTO 3 Inch Flush Valve Tanks |
Frequently asked questions
Which TOTO flappers does the THU500S replace?
It's listed as a replacement for THU138S, THU175S, THU331S, THU140S, THU299S, THU253S, THU277S, THU347S, THU275S, THU332S, THU369S and THU499S.
Will it fit a non-TOTO toilet?
No, it's designed specifically for select TOTO 3 inch flush valve tanks.
What's it made of?
A polypropylene body with a rubber sealing surface.