The Benefits of and How to Install Portable Composting Toilets for RVers

The Benefits of and How to Install Portable Composting Toilets for RVers
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Are you tired of dealing with the limitations of standard RV toilet systems? It's time to discover the practical, innovative, and eco-friendly advantages of Trelino® portable composting toilets. We understand the needs of outdoor enthusiasts like you because we've been there - and we've designed our products with quality, sustainability, and convenience in mind. Here you’ll find a comparison between portable composting toilets and standard RV toilet systems and a step-by-step installation guide for when you want to replace your cassette toilet option.

Cassette Toilets versus Composting Toilets


Emptying a Trelino

Finding suitable disposal stations to dump your black tanks can be a hassle. You may be in a more remote camping spot that is miles away from the closest dumping station. With Trelino® portable composting toilets, you can say goodbye to that inconvenience. Simply empty the urine canister when it's full (either in a public restroom or in nature) and tie up and dispose of the bag in the solids container. This emptying process only takes a couple of minutes and can be done in your campsite, making your camping experience much more convenient.


Traditional RV toilet systems waste gallons of water and rely on harsh chemicals to function. These features can be damaging to the environment and can smell. In contrast, Trelino® portable composting toilets are waterless and chemical-free. By choosing a composting toilet, you're embracing a more eco-friendly and space saving camping experience.

Odor-Free Experience

Composting toilet no smell

No one wants to deal with unpleasant smells while camping. One of the reasons you went on your trip was to enjoy the fresh air! With Trelino®, our intelligent aeration system and the addition of organic, drying materials ensure a completely odor-free experience. Say goodbye to the lingering stench of standard RV toilet systems.

Connection with Nature

Trelino® composting toilets offer a unique connection to nature. By creating the option to easily compost your waste, you can create valuable material to nourish plants and support wildlife. It's the perfect way to integrate sustainability and adventure into your camping trips.

How you can Incorporate a Trelino into your RV

Many Class B and larger RVs have a specific space set out for a cassette toilet system that would have been included in the vehicle. So if you’re tired of relying on time consuming dumping stations and smelly chemicals and you’re ready to make the switch to a composting toilet, here’s how! 

In just a few easy steps, you can switch out your old cassette toilet for a new composting one. 

Things to Keep in Mind: 

The old cassette toilet would have most likely been on a base. Any separating toilet with a standard height would be too high on that base, creating a toilet seat that is too high for comfortable use. 

The bathrooms in most motorhomes and vans would be completely covered in plastic. So at first, it might not be clear how to remove the cassette toilet. 

We designed our medium sizes specifically for this type of installation. This size fits perfectly on such bases or platforms while maintaining a comfortable height. Additionally, Trelinos are currently the most compact separation toilets on the market which makes them an easy fit in any bathroom! 

Before you Start:

The position of the separating toilet must be decided in advance. It is important to have enough space on the left and right for the arms and shoulders so that you don't feel squished when you are sitting on the toilet. You should also take into account any space at the back if there is a hinged lid on the toilet. The Evos would require up to 5 cm of space to the rear. The Origin M used here does not require any space at the back because the lid is completely removed before use.

Step 1 - Prepping the area 

First you should look for all the screws anchoring down the cassette toilet and then remove them one by one. As you can see in the photos, some were on the exterior wall and others were at the bottom of the cassette compartment. There can even be some screws behind the plastic panels that would need to be removed in advance with pliers. 

Installing a composting toilet
Installing a composting toilet


Step 2 - Shutting down the water pipe and power cable

A cassette toilet is hooked up to both electricity and water. Before you can really take apart the cassette set up, both of these must be removed. First connect the cables to a wire connector. Be sure to cut off the electricity beforehand!

The water pipe can then be removed from the cassette toilet and the remaining water drained out. The line is shut down using a plug.

Replacing a cassette toilet
Replacing a cassette toilet

Ideally, you would remove the supplying water hose completely. You can use a T-piece that would allow the water pipe to branch off to the toilet. This T piece is removed and replaced with a straight hose connector. Standing water in a residual pipe should be avoided at all costs. To find the T-piece you have to do some searching.

Step 3 - Removing the Cassette

After all screws have been loosened and all connections have been cut, the old cassette toilet in the bathroom can now be lifted out! Below you can now see a ledge with a base onto which the cassette toilet was screwed. Now you can attach your Trelino.

There are times when the toilet may not fit in with the plastic base that is already in the vehicle. This isn't an issue! You may just need to remove the plastic base in this case. 

Step 4 - Build mounting plate

build a base for a composting toilet

In order to get the Trelino firmly installed since the existing plastic base wasn't a good fit, you can instead build your own mounting plate out of a wooden panel. You can protect this piece from moisture and potentially mold with a slightly protruding plastic plate.

It is important to mention that you should use a plastic material that can then be easily sealed with silicone. Unfortunately, this is not possible with PP and PE. You can use a silicon caulk to seal. The base plate and later the rear wall were properly screwed together and then sealed to prevent moisture from penetrating. 

Step 5 - Attach your Trelino

Before attaching the Trelino, you should first double check all of the sealed points to make sure they are completely closed up. The separating toilet is then anchored in the ground with two screws. 

Now you have successfully replaced your cassette toilet with a Trelino! 

composting toilet in an RV


When comparing portable composting toilets to standard RV toilet systems, it's clear that Trelino® offers a superior solution. Embrace sustainability, convenience, and innovation by joining the Trelino® family and discover the wonders of the outdoors once again. Welcome to a new era of camping - quality made in Germany, continuous improvements, and made by campers for campers.

*These installation photos were provided by Gerfried und Olya at

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