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How Much Water Does An RV Toilet Use Per Flush?

How Much Water Does An RV Toilet Use Per Flush?

Water usage is a big deal in an RV, especially when we’re traveling or boondocking. So understanding how much water we’re using in various ways can be important. That’s why today we’re asking and answering the question “How much water does an RV toilet use per flush?” We’ll be taking a look at the water consumption of an RV toilet as well as a few steps we can take to conserve the amount of water used when flushing your RV’s toilet.

Let’s get things moving and flush out the facts! (Yeah, we know – that was bad. Let’s pretend we didn’t say it.)

How Does an RV Toilet Work?

Since there are different types of RV toilets, let’s first clarify that for the purpose of this post talking about water usage, we’re referring to the traditional gravity toilets originally installed in most new RVs – RV toilets that use water!

The water in your RV is plumbed to different locations, one of which is the toilet. When you step on the pedal at the base of the toilet, the blade valve opens to dump the contents of the bowl into the tank, and water moves from your fresh water tank into your toilet bowl to rinse it all down.

For a far more thorough explanation of how an RV toilet works, please see our post “The RV ‘Toilet Talk’: How Does an RV Toilet Work?

Do All RV Toilets Use Water?

No. Not all RV toilets use water. There are a number of different types of toilets an RV can have. These include composting toilets like the one our friends Tom & Cait Morton have. A composting toilet is technically a “dry flush” toilet.

Photo of several portable toilets

RV toilets can take many forms including gravity flow toilets, dry toilets like composting toilets, and portable cassette toilets like these.

There are other types of dry flush RV toilets on the aftermarket… and what they all have in common is that they don’t use water. So in addition to a composting toilet, this would include an incinerator toilet as well as any type of container-based toilet that doesn’t use water.

There’s even a dry flush toilet that uses a disposable liner to contain the waste. With this type of toilet, the waste drops into a liner, and “flushing” is actually the moving of the waste into an airtight container where it’s sealed in the liner, after which a new liner moves into the toilet bowl. An example of this would be the “Laveo” toilet by Dry-Flush, an interesting but expensive way to “go”!

How Much Water Does a Gravity RV Toilet Use Per Flush?

A gravity RV toilet doesn’t work the way a household toilet does. The amount of water used isn’t defined by a certain amount in a holding tank on the back of the toilet.

Instead, the amount of water used to flush a gravity RV toilet varies according to the length of time the flushing mechanism is activated.

Foot pedal being depressed, releasing water into the RV toilet bowl

With many RV gravity toilets, the amount of water used is determined by how long the foot pedal is depressed.

So, while we can’t answer the question with the precise amount of water required to flush a gravity RV toilet, we can tell you that you can flush an average RV toilet using somewhere around 16 ounces to flush liquid waste. It’s a good idea to use around 3/4 to one gallon of water to flush solid waste so that it doesn’t build up as a solid mass in the black tank.

How Can I Save Water When Using My RV Toilet?

There are a number of ways to save water when you have a gravity RV toilet. Some are more reasonable than others, depending on how you feel about things like using public toilets!

Let’s take a look…

If It’s Yellow, Let It Mellow…

We referenced the late great poet Don. T. Flush in our post on boondocking tips to wide acclaim.

Don is the poet who wrote:

If it’s yellow, let it mellow.

If it’s brown, flush it down.

While Don never won the Pulitzer Prize for Poetry, he did make a fair point if you’re an RVer trying to conserve water.

While we wouldn’t recommend holding a day’s worth of liquid waste in your RV toilet, you could conserve a bit of water by not flushing excessively when it isn’t necessary.

Use Residual Shower Water and Gray Water for Flushing

When you first turn on your RV shower, you’ve got to run up the hot water. When you’re trying to conserve water in an RV, letting that residual warm-up water go down the drain is a waste of a precious resource (gray tank capacity). We keep a gallon pitcher on board to collect that water, and then we can use it to flush the toilet so that we’re not wasting water.

Collecting the water expended while it warms for showers in a gallon pitcher.

As our shower water warms to our desired temperature, we collect the water in a plastic gallon pitcher and later use that water to flush our RV toilet.

Some people also like to use their gray water for flushing. This isn’t something we do, but you could certainly catch your dishwashing water in a plastic tub and then use it to flush your toilet. We’d recommend not sending large pieces of food down the toilet, though. Always wipe plates, pots, and pans clear of food particles before washing the dishes.

Use Campsite/Public Toilets

Lots of travelers conserve water by using public toilets or campground toilets. Many people aren’t at all bothered by the idea of public toilet use and they surely conserve water by doing so.

That’s not our personal modus operandi, but it does work for lots of RVers.

Use a Composting Toilet

You can opt for a waterless toilet as our friends Tom & Cait (referenced above) have done by installing a composting toilet. Lots of RVers swear by this modification and one thing is certain – it’s a HUGE water saver, as it uses absolutely no water at all!

Photo of a composting toilet

Composting toilets like t these don’t use any water at all!

Use a Dry Toilet

And you could also opt for a dry toilet like the Laveo mentioned in a previous section. The trade-off here is cost. Even after you’ve installed the toilet, the cost of operation remains significant because liner cartridges need to be purchased in order to use the toilet. Reviewers estimate up to $2 per flush – and that adds up quickly!

Do You Have Additional Tips for Reducing Water Usage in an RV Toilet?

We’ve outlined the tips that we recommend for reducing the water used by your RV toilet. But if you’ve developed a water-saving system that involves your RV’s gravity toilet, we’d love to hear about it! Please leave the details (not too graphic please!) in the comments below.

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