How to Replace an RV Toilet Flange?

How to replace rv toilet flange and reinstall

They say that your RV should feel like a home from home. Which is great, it’s why so many of us love RV camping. But it’s often not until you become a more experienced camper that you realize that your RV is also like your home in that there always seems to be a small repair, tweak or fix needed every few trips.

Keeping up with RV maintenance is a must for enjoyable camping trips, especially when it comes to your onboard RV toilet.

One of the most common problems boondockers encounter with their RV toilet is a broken or aging toilet flange. If that ‘goes’ while you are on the road you could be in for trouble – or at least left without one of the conveniences of RV camping that we take for granted – so it’s important that you know how to replace your RV flange and that you do it at the first sign of trouble.

What Does an RV Toilet Flange Do?

Your RV toilet flange connects the toilet itself to both the floor and to the black water waste tank. A loose flange can mean that the toilet isn’t stable to sit on and it can also lead to leaks and some rather nasty odors. A broken RV flange can lead to even more. Replacing it is (fortunately) not the hardest job to master but it can be a little more involved than you imagine as you’ll be working in a small space.

What follows is a simple step-by-step guide to replacing your RV toilet flange. If you ever need to, and it sounds like a job you don’t want to attempt – not everyone is DIY minded – remember that there’s nothing wrong with turning to a pro instead. The last thing anyone needs is for a botched toilet repair to ruin their latest road adventure.

Grab your tools

Before you do anything else you should gather up all the tools you are going to need to get the job done. 

For this job you’ll need:

  • Screwdriver
  • Chisel
  • Putty knife
  • Flange seal
  • Marine adhesive
  • Wrench
  • Old towels/newspaper
  • Angle grinder
  • Flashlight

1. Removing  your RV toilet

This part of the RV flange repair is easier than many imagine. Turn off the water supply and empty the toilet itself by flushing it. That done, disconnect the water line leading to the toilet altogether.

Remove the bolts holding your toilet to the floor. How easy this bit is depends on your brand of toilet. Some have bolts that pop off easily with a wrench others take a little more effort to shift. Work slowly and don’t get too frustrated, they will come out eventually.

Once you have removed the bolts lift the toilet out upwards (carefully) and set it safely aside. Next you’ll need to remove the flange seal. Many newer RV toilets have a rubber flange seal that is very easy to remove but if yours is an older model with a wax seal, you’ll probably have to chisel and scrape it off.

2. Finding the flange

Finding the flange is the next step. There should be screws holding it to the floor and they will have to be removed too. If they are screwed in too tightly, which may be the case, use your angle grinder to help you get them out.

Now, with the help of your flashlight, inspect the tubing that runs to the black water tank. The flange should be located between one and three inches down it. How it’s affixed will vary. Some are screwed in, some are glued in.

3. Uninstalling your old rv toilet flange

If you find that your RV toilet flange is screwed in removing it should simply be a matter of turning it counter clockwise until it detaches. If it has been glued in hit the seal with your chisel until the seal breaks and you can twist the flange off.

4. Finding the new flange

Screw the new flange into the black water tank in a clockwise fashion or, if it needs to be glued in do so with a liberal coating of waterproof marine adhesive. Replace the screws that hold the flange to the floor (installing new ones if you had to cut the old ones out) and add the new flange seal. Use a rubber one, it’s by far the better option, and then replace the toilet, ensuring that the bolts are nice and tight.

This is a tricky process. This is a great video to watch before you start, as it shows you just what NOT to do when you are replacing an RV toilet flange.

FAQs on RV Toilet Flanges

Q: How Will I Know That I Need to Replace My RV Toilet Flange?

A: There are several warning signs you should be aware of that will alert you to the fact that you need to replace your RV toilet flange:

Bad odors: If the flange is no longer doing its job – if it has cracked or come loose – those bad odors are from your black water tank.

Leaks around the toilet base: If the leakage is new the chances are that your RV toilet flange has cracked. If the toilet has always leaked – maybe you just bought the camper – then that may be a sign that the toilet flange that is installed is the wrong size.

The toilet rocks and moves: If using your RV toilet has become a disturbingly rocky experience then it’s almost certainly because the flange has cracked. To avoid damage to both the toilet and the floor of your RV it needs to be replaced as soon as possible.

Q. How Do I Know I’m Choosing the Right Size Toilet Flange?

A: Before you can replace your RV toilet flange, you have to buy a new one. And, as you’ll discover, they come in different sizes. In an ideal situation you’ll still have the manual that came with the RV toilet and it will tell you just what sized and style to buy. But unless yours is a brand new RV, the chances are that you don’t.

If you know the toilet’s model number, then you’ll often be able to look up the toilet flange size online using that. If not you are going to need to do some measuring. This will slow the repair down, as you’ll need to remove the toilet to do so. As inconvenient as this is it is a must, as fitting an incorrectly sized RV toilet flange is just as bad as dealing with a worn or cracked one.

What you will need to measure is the size of the waste hole. Most RVs have a 3 inch waste hole, some are a little smaller at around two and a half inches and occasionally, on an older RV one even smaller than that.

Q: What If My RV Toilet Flange Is Stuck?

A: Occasionally, an old toilet flange will seem to be so stuck that it seems impossible to budge. This happens if the screws have rusted or the marine adhesive holding it down has cured to where it seems solid as a rock.

Here removing it will be tricky, but as this video shows, it is possible, as long as you are comfortable using a powerful saw.

As the gentleman in the video mentions, a stuck toilet flange is usually the result of a bad installation in the first place, so it’s a problem you are only likely to encounter if you bought a used camper – which many do – and a toilet repair has gone bad before.

If you don’t feel comfortable with all the sawing and chiselling the video suggests call in a plumber. The extra expense of doing so over doing it yourself will be worth it if it prevents damage to your black water tank, as that is a far more expensive repair that WILL need a pro to execute.

Q: Where Can I Buy a New RV Toilet Flange?

A: The good news is that standard size RV toilet flanges are easy to find. 

They are carried in most specialist RV supply stores, big box stores like Walmart and online at Amazon and other similar sites. They are not too expensive either; you can expect to pay between $10 and $40 depending on the model and size you need.

Q: When Should You Replace An RV Toilet Instead Of Repairing It?

A: The first thing we should mention is that just because your RV toilet leaks does not mean it needs to be replaced. As you will have learned by reading this far, the problem is often the RV toilet flange rather than the toilet itself, and by replacing that you’ll solve the problem without needing to buy – and install – a new RV toilet.

Another reason RV toilets leak is that a water valve has gone bad. Replacing an RV water valve is a simple process – easier than replacing a flange – and that may solve a leakage problem too.

This video walks through replacing the water valve on a Dometic RV toilet – one of the most popular brands – but the procedure is very similar for all toilet brands:

But the fact is that a toilet in your RV does not have to be broken for you to want to replace it. If yours is an older camper you may be missing out on some of the newer innovations in RV toilets and upgrading will make using the bathroom in your RV a more pleasant and even more eco-friendly process.

With this in mind, let’s take a look at some of the options you’ll find if you do decide to opt for a new model.

Choosing a new RV toilet

Almost all RVs are equipped with a gravity flush toilet. But these days they can vary considerably from model to model.

Here are some tips to keep in mind as you shop:


The two most popular RV toilet brands are Thetford and Dometic. Both companies are very well known in the RV plumbing and appliances space and have been around for decades, so products purchased from them are backed by solid, long-established customer service practices. There are other brands on the market – especially if you shop online – but make sure you do your homework before opting for one of them over the tried and tested brands.


There are two basic choices when it comes to the material your RV toilet is constructed from; China or plastic. If you like the ‘at home’ look China is the right choice, but if you are OK with a camping toilet looking like a camping toilet, then plastic is fine and it is the less expensive choice, as well as the option that’s easier to take care of.

In terms of color your choices in either China or plastic are almost always going to be white or bone (with bone being harder to find). Not exciting decor wise but as is the case for your bathroom at home you can always make use of toilet accessories like toilet seat covers to liven things up a little.


Some newer RV toilets are anti-microbial. Some are low water, making them a very eco friendly choice. Some even have a bidet attached to them! And you no longer have to rely on a gravity flush, as there are (pricier) RV toilet models that use electricity or air to flush instead. The fact is that if you have a standard 21/2-3 inch waste hole in your RVs floor you can choose any of these innovative new options, as long as you are willing to pay more. 


Before you spend a dime on a new RV toilet, you need to ensure it is going to fit. In addition to ensuring the waste hole is large enough, you also have to take width and height into consideration. 

Measure the available space before you start to shop and match it to the specs given for the RV toilet models you are considering to help ensure you’re making the right decision. 

Care tips for RV Toilets

Whether you replace your RV toilet flange or choose to purchase and install a new RV toilet altogether, there are some things you can do to help ensure that your newly fully functional RV toilet keeps working the way it should for as long as possible.

Here are some of the most important of those things:

Always use RV toilet paper

Have you ever seen RV toilet paper in a store or advertised some place and dismissed it as a marketing gimmick? While there are some things marketed to RV enthusiasts that are gimmicky, this is not one of them, and making use of it will help prevent all kinds of nasty problems, including premature aging of the RV toilet flange and its seal, blocked black water tanks and blocked piping. Standard toilet paper can even stick to the water level sensor in your black water tank and lead to false readings.

Why is RV toilet paper different? 

They design it to disintegrate faster than standard toilet tissue and some offerings, like the Thetford Quick-Dissolve RV Toilet Paper, is 100% biodegradable, which is more eco-friendly.

Believe it or not, this is a rather controversial subject in the RV community. Some experienced RV owners say that some types of standard toilet paper are OK for RV use, as long as you ‘test’ them first.

This video demonstrates the process and ‘tests’ several types of commonly used toilet tissues, but in a nutshell you take a few squares of tissue, submerge it in a jar of water and if it dissolves within a few seconds, it is probably OK for RV use.

Treat your black water tank

One thing that is less controversial and generally agreed to be a must is treating your RV’s black water tank.

These treatments come in liquid and powder forms and should be used regularly to help keep your tank and your RV bathroom’s plumbing system in general in the best possible shape.

Don’t put repairs off 

If you have never had to replace an RV toilet flange, now that you know more about how it’s done you may have decided that all sounds like a lot of hassle. And if your RV toilet is only leaking a little, or shifting very slightly, it’s tempting to put off thinking about repairs until after your next trip. Or the trip after that. Or until it gets a bit worse.

The fact is, however, that RV toilet repairs should be made as soon after you realize there is a problem as possible. Problems like a cracked flange or an aging seal will not get any better, they will only get worse. Dealing with a broken RV toilet as an emergency is about as far from fun as you can get when camping and that is what you risk if you put off doing repairs.

Should i choose a composting RV toilet instead?

RVing is all about enjoying the great outdoors. Helping preserve the environment so we can carry on doing so is something that every camper should be doing. One way that some campers are choosing to do that is by switching out their standard water based RV toilet for a composting RV toilet.

This is another matter of lots of discussion. Some people are afraid that composting toilets are unsanitary or unpleasant to use. Others like the idea because there is far less regular maintenance required, less water is wasted and if you are the kind of camper who likes to go boondocking well off the beaten track a lot it certainly reduces the amount of water you’ll use, allowing you to potentially ‘stay out’ longer.

This video offers a high-level overview of the pros and cons of composting toilets for RV use and is well worth a watch if it is something you are considering:

We hope you never have to make use of the knowledge you’ve learned here, but if you go RVing long enough, the chances are that you will eventually have to deal with replacing an RV toilet flange and hopefully this piece has helped you feel more prepared to do so!


4 thoughts on “How to Replace an RV Toilet Flange?”

  1. Can I install an offset toilet flange to move toilet back 2 inches on my camper ? And if so where do I purchase it

  2. Nice page. Thanks. This helped. A lot. Having to replace my RV toilet has become a lot more complicated. Gonna have to build a pedestal for mine because not enough room to center of drain to install toilet on drain. Might be a good subject to cover incase others run into this issue. Got the advice from an RV parts specialist at camping world.

  3. Daniel A oliver

    I’m trying to replace a toilet flange in a nomad weekender rv. Unsure of year. The flange for the toilet is 3 in mpt. The top of the black water tank has a molded on fpt fitting. The flange threads don’t quite reach the tank fitting…and the tank fitting is slightly larger. Ive been to my local rv store, and I have several fittings from home depot. I cant find anything that fits. The toilet was removed when I bought the camper. What am I missing?

Leave a Comment

Your email address will not be published. Required fields are marked *