TOTO THU500S Universal Flapper and Fill Valve Kit
- Two-piece kit, flapper plus float fill valve
- Replaces the THU499S flapper, universal fit per the title
- 1.25 inch NPT thread, compression inlet
- G connector outlet, 1.25 inch connection
- Rubber flapper, stainless steel exterior finish listed
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A flapper and fill valve combo from Toto, for a toilet repair where both parts are worn. The listing leaves out tank fit and flush valve size, so confirm those before ordering.
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ASIN: B013TH1VHGModel: THU500SCategory: Toilet Flappers
Overview
A float valve shuts off the water when the tank fills, and the Toto kit pairs it with a universal rubber flapper that seals the flush valve. The valve connects with a compression inlet and a G connector outlet.
Replacing the flapper and fill valve together removes the two usual causes of a running toilet in one job. The limitation is fit: the listing calls the flapper universal but never states which flush valve size or toilet models the kit covers.
Who it's for
Homeowners replacing parts in a Toto tank can handle both the flapper and the fill valve in the same visit. Buyers with older Toto models, or with a different brand, should check the part numbers against the tank before buying.
Pros and cons
- Flapper and fill valve in one kit
- Float valve controls tank fill
- Rubber flapper seals the opening
- Part numbers named for lookup
- Flush valve size not listed
- Compatible toilet models not listed
- Stainless finish claim is odd for a flapper
Performance notes
The rubber flapper lifts during a flush and drops back to seal the opening, so a worn or warped flapper lets water trickle into the bowl. The float valve opens as the tank empties and closes as the float rises, which sets the water level for the next flush. The connection sizes listed matter when matching the fill valve to the supply line and tank.
Specifications
| Brand | Toto |
|---|---|
| Model | THU500S |
| Dimensions & fit | |
| Outlet Connection Size | 1.25 inches |
| Inlet Connection Size | 1.25 inches |
| Thread Size | 1.25 inches NPT |
| Item dimensions | 11.02 x 8.78 x 3.78 inches |
| Construction & materials | |
| Material Type | Rubber |
| Included components | |
| Number Of Pieces | 2 |
| Other details | |
| Valve Type | Float valve |
| Outlet Connection Type | G connector |
| Inlet Connection Type | Compression |
| Set Name | Flapper and fill valve combo |
Frequently asked questions
How large is the Toto THU500S kit?
The listing gives 11.02 x 8.78 x 3.78 inches, which is the kit size. It does not list tank clearance.
Is this a complete toilet?
No. It is a two-piece repair kit with a flapper and a fill valve.
Why does the listing say stainless steel?
The exterior finish field reads stainless steel while the material field says rubber. Treat the flapper as rubber and confirm with the seller.