What are the different types of toilet tank seals?

Toilet Tank Seals (Tank Seals / Toilet Rubber Gaskets) come in seven common types based on structure, installation location, and function. They are used in different areas such as the fill valve, flush valve, and the connection between the tank and the toilet bowl.

Common Types of Toilet Tank Seals

1️⃣ Flush Valve Seal / Flush Valve Gasket

Located at the **base of the flush valve**, it ensures watertight performance when draining the tank into the toilet bowl.

Features:

* Circular, large diameter (typically 50–90mm)

* Materials: **EPDM rubber/NBR rubber/silicone**

* Requires flexibility, wear resistance, and scale resistance

Commonly found in:

* Single-button flush valves

* Dual-button energy-saving flush valves

* Vintage siphon-type flush valves

2️⃣ Fill Valve Seal / Inlet Valve Gasket

Located at the **bottom of the fill valve**, it seals the opening between the fill valve and the tank base to prevent leakage.

Features:

* Inner diameter typically 20–30mm, outer diameter approx. 40–60mm

* Mostly flat circular rings

* Must withstand water pressure and resist aging

Commonly found in:

* Float-type inlet valves

* Side-inlet/bottom-inlet valves

3️⃣ Tank-to-Bowl Gasket

Used between the **water tank and toilet bowl** (two-piece toilets).

Features:

* Large gasket

* Commonly rubber triangular, donut-shaped, or with reinforced edges

* Must be durable, crush-resistant, and vibration-resistant

Purpose:

* Cushions and prevents leakage during flushing

* Suitable for two-piece toilets

4️⃣ Push Button Seal

Used in **dual-button or single-button assemblies** to prevent leaks around the button area.

Features:

* Typically small seals or O-rings

* Commonly used in push-top tank lids

5️⃣ Tank Bolt Washer / Rubber Washer

Used at screw holes connecting the tank to the toilet bowl.

Features:

* Small rubber washers

* Typically paired with metal washers

Function:

* Prevents water leakage from screw holes

6️⃣ Overflow Pipe Seal

Used at the **overflow pipe connection point within the flush valve assembly**.

Features:

* Small to medium-sized circular gasket

* Commonly found in integrated flush valve assemblies

Function:

* Ensures no leakage at the connection between the overflow pipe and valve body

7️⃣ O-Rings / Micro Seals

Used for internal moving parts in inlet valves or flush valves, such as:

* Valve core body

* Float mechanism

* Small sliding structures

Characteristics:

* Commonly found as small black or red O-rings

* Included in repair kits