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What Are the Parts of an RV Toilet & How to Replace Them?

RV toilets have an essential job. So when they break or leak, it’s tempting to go into panic mode. You may begin to worry about how complicated the repair will be or how much replacement RV toilet parts will cost. And how will you go to the bathroom in the meantime when your only toilet is out of order?

Stay calm because we have some good news. RV toilet parts are relatively easy and inexpensive to replace. And even the more complicated repairs will only take about half an hour to complete. 

Ready to learn more? This article will help you better understand RV toilet parts and how to replace them. Let’s get started!

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How Do I Identify My RV Toilet?

Before replacing any parts, it’s essential to know what type and model of RV toilet you have. This information will ensure you order the correct replacements.

RV pedal-flush toilet
Before repairing your toilet, you need to know the type and model number for ordering parts.

While there are many different RV toilet types, we’ll focus on the two most common factory-installed units: gravity and macerating toilets. 

Pro Tip: Looking for information on the other RV toilet types? Read this Practical Guide to the 6 RV Toilet Types

One easy way to identify your toilet type is by looking inside the bowl. A gravity-flush toilet will have a hole at the bottom of the bowl covered by a flap. The flap opens when you press the foot pedal or handle to flush, allowing the waste to drop down through the hole and into your black tank. As the name implies, these toilets use gravity to move liquids and solids into the waste tank. 

Macerating toilets are slightly different. The hole where the waste flushes through is typically smaller than a gravity toilet, and there is no flap. These toilets have a button for flushing and rely on a pump and grinder to move the liquids and solids through the RV’s plumbing and into the black tank.

RV Gravity-Flush Toilet
Gravity-flush Toilet
RV Macerating Toilet
Macerating Toilet

Once you’ve identified your toilet type, you’ll want to locate the brand and model number for ordering parts. Most often, you’ll find this information on a sticker on the backside of your toilet near the floor. You may need to use a mirror or take a photo of the serial number with your phone if you can’t get your eyes on it. 

What Are the Parts of an RV Toilet? 

RV toilet parts will vary depending on the toilet type. As you might imagine, a gravity toilet’s components are simpler and cheaper, which is good news when you need to replace them. Conversely, the grinding and pumping mechanisms make a macerating toilet’s parts more complex and expensive. 

So why would manufacturers install macerating toilets in an RV when gravity toilets are more cost-effective and easy to repair? The answer requires a deeper look at the differences between these toilet types. 

RV Macerating Toilet
Unlike gravity-flush units, macerating toilets don’t have to sit directly over the black tank. In fact, one of our RV toilets is on the slide!!

Without a pump, gravity toilets rely on the weight of the wastewater to empty the bowl. This means manufacturers must position them directly over or very close to the black tank, limiting floor plan options. No grinder also means that solids, including toilet paper, remain solid, which could lead to black tank or sewer hose clogs. 

Pro Tip: You can prevent sewer hose clogs when using a gravity flush toilet by connecting an external macerator pump to your black tank. Learn more here: Simplify Black Tank Dumping with an RV Macerator Pump

On the other hand, macerating toilets pump and grind liquids and solids, so these toilets don’t have to be directly over the black tank. This design allows manufacturers to be more creative with floor plans, even including a second bathroom in some RVs. Plus, RVers don’t have to worry about clogs as the grinder liquifies any solid waste. 

Now that you better understand the primary RV toilet types and their pros and cons, let’s look at their parts.

Gravity-Flush Toilet Type

Since gravity-flush toilets are the most common and easiest to understand, we’ll explain their RV toilet parts first.

Seat and Cover

Every RV toilet has a seat and cover. Most gravity-flush toilet seats and covers will be made of plastic to save weight. Occasionally, you can find ones made of porcelain or wood, and replacements are available in various sizes to fit your specific toilet design. 

Pro Tip: Check out these 6 Easy Ways to Upgrade Your RV Toilet Seat to make your RV bathroom a little more luxurious.

Thetford Gravity-Flush
RV toilet lids will sometimes indicate the brand of the toilet if it’s original to the unit.

Ball or Flapper Valve and Seal

Remember how we said gravity-flush toilets have a flap that opens for the waste to drop through? The technical name for this is a ball or flapper valve. Additionally, this valve will have an O-ring seal, which keeps the toilet water in the bowl until flushed. 

Mission Automotive Flush Ball Seal fits Dometic...
  • Perfect For 300 / 310 / 320 Models -- Our flush ball seals /...
  • High-Quality Material, Made To Last -- Our valve seals are made...
  • DIY Install Saves Money! Don't go out an buy a new toilet or pay...

Water Valve 

Just like a residential toilet, an RV toilet bowl fills with water to help flush and rinse away waste. This water enters the bowl via a water valve. So, where does this water come from? Because RV toilets don’t have holding tanks like residential models, the water comes directly from the camper’s fresh water tank or a city water connection.

Halotronics Upgraded RV Water Valve Replacement...
  • Features | This replacement kit includes all the necessary parts...
  • Quality | Strong and durable ABS plastic ensures a perfect fit...
  • Specifications | Included parts: water valve, hose clamp, and...

Floor Flange and Seal

The floor flange and seal are the last RV toilet parts you need to know about for gravity units. They prevent water from leaking onto your bathroom floor by creating a water-tight seal between the toilet and the pipe leading to the black tank. 

RecPro RV Toilet Closet Flange | 4x3 | ABS Plastic...
  • 4x3 closet flange fits most 3" and 4" waste lines
  • Universal hole pattern which fits most toilets
  • Available with an optional wax seal, both necessary parts for...

Macerating Toilet Type

Next, let’s look at the parts of an RV macerating toilet. This type is more complex, but we’ll take a high view, so you don’t get bogged down in unnecessary details. 

Seat and Cover

There’s no surprise here: macerating toilets have seats and covers too. These parts can be porcelain, plastic, or wood and come in various sizes to match your commode.

Internal Plumbing and Macerator Pump 

When a macerating toilet is flushed, the waste is sucked directly from the toilet bowl into a macerator pump. This device has an internal impeller that grinds any solids into a liquid. The liquified waste then gets pumped through a discharge tube and a pipe leading to the black tank. 

Thetford 38056 12V Toilet Discharge Pump
  • Country of Origin: UNITED STATES
  • Fits multiple makes and models (contact seller with your vehicle...
  • Package Dimensions: 16.8 " L x 15.9 " W x 5.4 " H

Water Control Valve

Macerating toilets use more water than gravity flush toilets. This is because the pump needs plenty of water to function correctly. Without water flow, the solid waste would seize up the impeller blades and clog the internal plumbing. That’s why the water control valve is so important; it allows the proper amount of water to flow into the bowl and through the pump.

Control Panel

Most RV macerating toilets have a control panel with buttons for flushing. Often you’ll find an “add water” and a “flush” button. Units that automatically add water will instead have a water-saving button for liquid waste and one that uses more water for solid waste.

Thetford Tecma Control Panel
This macerating toilet control panel has “Water Saver” and “Normal” flush buttons.

Tank Sensors 

Pumping waste into a full black tank is problematic. The slurry in your black tank could backflow through your pipes, creating a stinky mess. That’s why RV macerating toilets have built-in tank sensors. These sensors will warn you not to flush and, in some cases, prevent you from flushing if the black tank is full.

How Do You Fix an RV Toilet? 

How you fix an RV toilet will depend on the problem and toilet type. One thing is for sure, though, you don’t want to put off this project. Not only is it inconvenient to have a malfunctioning potty, but issues like water leaks can cause significant damage to your rig.  

If your RV toilet is clogged but not broken, we have a separate guide on how to unclog an RV toilet.

If your toilet is leaking water, has a defective part, or if the macerator pump is failing to pump and grind waste, keep reading. 

RV toilet leak points diagram
This is a diagram of an RV gravity-flush toilet, indicating the parts that are most likely to leak.

How Do You Change a Water Valve on an RV Toilet? 

To change a water valve on an RV toilet, you’ll start by shutting off the water supply and water pump. Then, flush the toilet to drain any remaining water in the lines. 

You may be able to access the leaking valve without removing the toilet, but if that’s not possible, unscrew the mounting bolts and remove it. 

Next, unscrew the water lines, removing any pipe clamps and screws. Some residual water may drain out of the lines, so have a towel on hand. 

At this point, you should be able to detach the bad flush valve and pop a new one in its place. Screw the new valve and water lines back into place and replace the toilet (if necessary). 

How To Fix A Leaking RV Toilet | Valve Replacement- Dometic 300 301 310 series how to fix rv toilet

Turn the water back on and test for leaks. If the new valve leaks, ensure you’ve adequately tightened all screws, water lines, and pipe clamps.

How Do You Replace a Toilet Flange on an RV? 

Start by shutting off your water supply and water pump, then empty your black tank. Next, remove the toilet, then the flange seal. This RV toilet part can get sticky and may require a little effort to pry loose. 

Remove the screws holding down the flange, then turn the whole part counterclockwise to remove it. To install a new one, simply reverse the process. 

Screw the new flange into the opening clockwise, then replace and tighten any screws holding it in place. Put the new seal on top, and carefully set the toilet straight down over the new flange and seal. Bolt the toilet down, and you’re done. 

Airstream Travel Trailer toilet Flange removal

How Do I Fix the Ball or Flapper Valve on My RV Toilet? 

You’ll likely need to replace the seal or gasket around the ball or flapper valve if your toilet bowl is not holding water. But first, give the gasket a good cleaning. Sometimes debris can prevent this RV toilet part from sealing properly, and cleaning it may fix this issue.

If you need to replace the seal, you’ll want to turn off your water supply and water pump. You may even want to flush your black tank to prevent nasty odors during the repair. 

For one-piece toilets: Put on a pair of gloves, open the ball or flapper valve, reach in and pull the seal out. Then, close the valve, and press the new seal into place, making sure it fits snuggly around the rim of the valve.

RV Toilet Ball Valve Seal Replacement

For two-piece toilets: You’ll need to take the toilet bowl off its pedestal. Start by removing the cover or shroud at the base, then unscrew the clamp. The toilet bowl should easily lift off at this point. Replace the old seal with a new one, and reverse the process to put the toilet bowl back on the base. 

RV Toilet Not Holding Water? - Install a New Toilet Seal!

How Do I Repair a Macerator Toilet Pump?

Most likely, you’ll want to hire an expert to repair your macerator toilet. These units have complex mechanical and electrical components that won’t be easy to fix. If you’re a novice RVer or not mechanically inclined, it’s better to leave this job to the pros. 

However, if you feel confident in your repair skills, we’ve highlighted some basic troubleshooting tips below. But first, make sure the water and power are off before taking anything apart to prevent leaks or electrocution.

When the toilet doesn’t flush due to a malfunctioning tank sensor, you’ll need to dump and flush your black tank. Some RVers recommend locating the yellow sensor wire and cutting or disconnecting it if the sensor is still reading full after emptying the black tank. However, cutting the yellow wire on a macerating toilet should be a last resort as this will disable the sensor, and your black tank could overflow.

Troubleshooting Dometic 7640 Macerator Toilet Part 3

The impeller is likely broken if the toilet makes a grinding sound when you flush it. In this case, you’ll need to disassemble the toilet and replace the macerator pump. 

If you hear the pump whining, this generally indicates a blockage. Carefully remove the toilet and disassemble the toilet’s internal plumbing. Inspect the pump and discharge tubes, clear any blockages, then reassemble and flush. 

Is Fixing an RV Toilet on My Own Worth It?

When your RV toilet is your only option for relieving yourself, knowing how to fix the common issues we addressed above can really save the day. Most RV toilet parts are inexpensive, and the repairs are straightforward. So if you can do it yourself, why wouldn’t you? 

You’ll save time and money, plus you’ll walk away with a feeling of accomplishment. And who knows, maybe that feeling will follow you throughout your adventures, giving you the courage to conquer new challenges on the road and off.  

repairing leaking RV toilet
Doing RV repairs yourself can save a lot of time and money.

You can avoid the hassle of leaks and clogs altogether with a composting toilet. Plus, there are numerous other benefits. Find out: What’s So Great About RV Composting Toilets?

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About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

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Sunday 30th of July 2023

Our gravity toilet wasn't holding any water in the bowl and we finally realized that the flap itself, that opens and closes when you push the pedal, is cracked. Can that part be replaced, or is it included in some other replacement set, or do we have to buy a whole new toilet?

Mortons on the Move

Thursday 3rd of August 2023

Oh no, you will have to look up your specific toilet, but usually thetford and dometics can replace the flaps or ball flush. Sometimes its part of a larger kit or entire base.


Thursday 29th of December 2022

Black plastic piece that connects to. The water supply in the back of toilet can I just glue it to connect to water

Mortons on the Move

Sunday 26th of March 2023

usually, water supply should be threaded, if its black plastic its probably ABS and you will need ABS or ABS to PVC glue.