If you’ve ever looked up RV toilet parts online and felt like you were reading a foreign language, you’re not alone. RV manufacturers love using different names for the same exact part, and even different models from the same brand will use their own terminology. What one diagram calls a waste ball, another calls a blade. A water valve might appear under three different names depending on the manual.

This guide breaks down the most commonly confused RV toilet parts so you can finally understand what you’re looking at—and buy the right part the first time.

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Why RV Toilet Terminology Is So Confusing

Unlike residential toilet manufacturers, RV toilet companies such as Dometic and Thetford frequently reuse internal components across multiple models—but label them differently in diagrams, manuals, or parts lists. Add marketing language on top of that, and you end up with three or four names for the same function.

The good news? Once you learn the pattern, everything makes sense.

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The Big Translation Guide: RV Toilet Parts With Different Names but the Same Function

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1. Water Valve Assembly (a.k.a. the Fresh Water Valve, Inlet Valve, Water Module)

This is the part that controls how water enters the bowl during a flush.

You may see it called:

• Water Valve

• Fresh Water Valve

• Inlet Valve

• Water Module

• Fill Valve

• Flush Valve (often used incorrectly)

What it actually does:
Opens briefly to let rinse water flow.

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2. Waste Ball / Blade / Slide Valve

This is the part that opens to drop waste into the holding tank.

If it rotates (typical of Dometic):

• Waste Ball

• Ball Valve

• Ball Gate

If it slides (common in Thetford):

• Blade

• Slide Valve

• Shutter

• Gate

Same job, different motion. All of them separate the bowl from the tank.

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3. Ball Seal / Blade Seal / Bowl Seal

This rubber seal keeps odors down and water in the bowl.

Names you’ll see:

• Bowl Seal

• Ball Seal

• Blade Seal

• Waste Valve Seal

• Flush Seal

• Valve Gasket

One seal, many interpretations.

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4. Flush Mechanism (Pedal, Handle, Linkage—It’s All Connected)

Depending on the model, the flush can be activated by:

• Foot Pedal

• Flush Lever

• Flush Handle

• Actuator Arm

• Linkage Assembly

• Control Arm

These all refer to the parts that move when you flush.

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5. Vacuum Breaker / Anti-Siphon Valve / Backflow Preventer

RV toilets must prevent dirty tank air or water from contaminating the fresh-water line.

Manufacturers may call this piece:

• Vacuum Breaker

• Anti-Siphon Valve

• Backflow Preventer

• Check Valve (used incorrectly but still common)

Same protection, different terminology.

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6. Mounting Hardware (Floor Flange, Closet Flange, Base Seal)

The parts that secure the toilet to the RV floor are often labeled differently.

Common names:

• Floor Flange

• Closet Flange

• Base Seal

• Toilet Mounting Gasket

• Hold-Down Kit

All are referring to the mounting system.

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7. Water Supply / Flush Tube

This is the tube or hose that carries water into the bowl.

Watch for terms like:

• Flush Tube

• Water Supply Line

• Fill Tube

• Rinse Tube

• Bowl Rinse Hose

Again, all describing the same simple part.

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Why Knowing These Names Matters

Understanding RV toilet terminology helps you:

✔ Order the right replacement part

✔ Compare models accurately

✔ Follow diagrams correctly

✔ Understand installation or repair videos

✔ Avoid buying duplicates labeled under different names

Whether you're maintaining your own RV or running an RV parts store, decoding this “multi-language” system saves time and money.

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Final Thoughts

RV toilet parts may be labeled in confusing ways, but they’re not nearly as complicated once you understand the naming patterns. Consider this your official translation guide for navigating diagrams, manuals, and product listings across Thetford, Dometic, SeaLand, and other RV toilet brands.