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Replacing an RV Toilet with a Composting Toilet (The Full Guide)

Having a bathroom to use while on the road or camping off the grid is a big advantage for many RV owners. No need to stop at specific places to use public restrooms. 

Some also don’t like the experience of needing to drain the RV black tank, and feel that their bathroom could be more environmentally friendly and functional. Rather than using an RV toilet, they might elect to use a composting toilet.

A composting toilet is different from a traditional toilet or an RV toilet in that it produces compost. There are several reasons why one would elect to replace a traditional toilet with a compost toilet and we’ll discuss those.

First, what is a composting toilet?

Physically, a composting toilet is basically a toilet with no plumbing. Some models have a separator that pushes liquid waste into one bucket and solid into another for the purpose of storage and future composting.

One could simply say that a composting toilet is like going to the bathroom in a oversized bucket, though it certainly provides more advantages and comfort than a literal bucket.

Is it more environmentally friendly?

Composting toilets are most environmentally friendly for a couple of reasons. A composting toilet doesn’t need water, which lowers your water consumption, considering that most regular toilets use a significant amount of water just to flush waste away.

Composting toilets also encourages humans to use their own waste for fertilizer. If you plan to garden, you can store the solid waste and use it later to grow food and foliage. Some might prefer this over purchasing expensive fertilizer and hauling bags to their vehicle.

Is a composting toilet easier?

Yes and no. A self-contained composting toilet removes the need for a black tank. This could come as good news for some who don’t want to have to use their sewer hose to empty their black tank.

The downside is that you still have to empty it. Putting sawdust and other absorbers into the toilet tanks before using it can alleviate the smell and make it safer to remove the waste.

We recommend wearing disposable gloves and a mask when emptying waste, but that’s also recommended when emptying the black tank.

The easiest way to empty is to prepare a bio bag outside. Have someone help you carry the entire toilet outside. Remove the waste container or containers and empty them into either the bag, or throw them into your compost pile/garden.

Does a composting toilet flush?

Not really. Flushing implies that the composting toilet uses running water to drag waste away. The composting toilet has a lever that opens to the containers below, where the waste simply falls.

Do they smell?

They can. The big difference is that the smell might be different from what you are used to. A composting toilet will more likely smell like a farm, which isn’t a bad thing to most.

A traditional RV toilet has direct access to the black tank on your RV, with an open line. This can also smell like a bathroom or sewage for a variety of reasons, ranging from being too full, to just generally having waste inside.

If a composting toilet says it doesn’t smell, they mean when the compost is inside. The composting toilet is also likely to have some sort of smell anyway.

How do I replace my toilet?

The installation of a self-contained compost toilet is quite easy. It’s a matter of getting your old toilet out.

You’ll want an adjustable wrench, some disposable gloves, a garbage bag, a screwdriver, and probably another person to help lift.

  1. You’ll first want to disconnect and shut off the water lines to your toilet. This is generally done from the back of the toilet and involves turning the knobs to shut off water.
  2. The toilet is likely bolted down, with the bolts under the plastic cover. Remove the plastic cover with a screwdriver or some sort of wedge.
  3. Remove the bolts from the floor.
  4. You probably need to disconnect the toilet from the black tank itself. This includes a possible seal located directly in the back of the toilet. You’ll want to find a way to cover the hole and seal too.
  5. At this point, you may be able to lift the toilet up and out.

There isn’t really an installation for a self contained compost toilet. The biggest thing to do is bolt it in place if necessary so it doesn’t move. If you plan to do a centralized system or have two bathrooms, you’ll want to follow the instructions that came with the toilet.

How often should I empty a composting toilet?

The answer depends on the toilet capacity and how many people around you are producing waste. The toilet might need to be emptied a couple times a week. 

The method is actually quite similar to your black tank: You are going to have to empty out the black tank, likely once a week or more when it’s being used alot.

You’ll also know earlier if your composting toilet is about to overflow. It could start to smell, and the attempt at “flushing” the toilet can expose the inside of the container. The downside to overfilling a composting toilet is that it will become heavier with more waste.

What should I do with my black tank?

Our suggestion is to clean it up, drain it again, and leave it on. The black tank can be uninstalled and stored or thrown away, but it might be easier to keep it on if you plan to sell your RV at some point. You may also discover that for whatever reason, the composting toilet doesn’t fit your preferences. 

Keeping the black tank on until you are absolutely sure you aren’t going to use it prevents future headaches.


Installing a composting toilet certainly has key benefits for those who want to be nice to the environment. Gardeners and people who grow their own crops will also get more opportunities for cheap fertilizer using their own waste to grow food.

The actual installation of a composting toilet is the easiest part. Removing your previous toilet is a matter of having the right tools and some help lifting the toilet out.

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