How Much Water Does An RV Toilet Use Per Flush?

One of the great things about camping in an RV versus other options is the RV toilet. In fact, that one little convenience changes all kinds of things about a camping trip. There’s no need to worry about finding a gas station bathroom, emptying a portable toilet (and the mess that can result if things go wrong) and it’s just NICE to have a bathroom in your ‘home from home’ on the road.

But how much thought do you ever give to your RV toilet? Like, how much water does an RV toilet use per flush?

The answer to that specifically depends on the model your camper boasts, but on average, an RV toilet needs a half gallon of water to flush properly, which is a lot less than your toilet at home, which uses between 5 gallons if it is an older model (pre-1990) or somewhere between 1.5 and 2.5 gallons if it is a newer, low flow model.

But just how does an RV toilet use that small amount of water to function? And how does the water system in an RV differ from that in your home in the first place? These, and other RV toilet related concerns, are what we are going to take a closer look at now.

How The Bathroom Water System Works in an RV

A Modern RV camper van bathroom with shower, sink, and toilet

Most RVs have running water available in the kitchen area to wash dishes as well as in the bathroom in the sink, shower and to flush the toilet.

The water system in your RV bathroom is divided into two parts: one for the sink and shower and another one for the RV toilet. Both make use of the same fresh water supply, whether it’s from your tank or from city water. Your RV sink and shower, like your RV kitchen sink, emits gray water that is full of debris, body oil, detergents, and shampoos.

Your toilet, on the other hand, produces “black water,” which is water tainted with raw sewage and toilet paper. To avoid clogged tanks in RV water systems, you must use specific toilet paper, which is something we’ll get to in a moment.

Grey Tank vs. Black Tank

RV Toilet Chemicals
A Cassette RV Toilet

Grey water is stored in the gray tank. Although gray water isn’t quite as dangerous as raw sewage, you really should be careful when and how you dispose of it. This water is dirty, yet it’s nothing compared to the water in the black water tank.

As previously stated, this is where you’ll collect your RV’s human waste and sewage. How you empty this tank is rightly governed by tight rules and regulations. To avoid waste accumulation – and terrible smells – RV black water tanks must be cleaned and deodorized on a regular basis with particular cleansers and deodorizers.

What Type of Toilet is in Your RV?

What type of toilet is in your RV (Cassette toilet)

That standard toilet you’ll find installed in most RVs is known as a gravity flush toilet. Most models look a lot like the toilet you have in your bathroom at home, but they function very differently. Here’s a closer look at the way a standard gravity flush toilet works and what your alternatives are.

Gravity Flush Toilets

Gravity flush toilets are constructed of either porcelain (in higher-end versions) or plastic (in lower-end models). The majority feature a foot operated flush that unlocks a hatch in the bowl’s bottom. When you’re finished, the pedal also rinses the bowl with water.

The waste and rinse water are then pulled down into the black water tank thanks to gravity.

As this is the standard installation in an RV, you should never have to worry too much about the actual plumbing, just making sure you empty the black tank properly and keep everything clean.

There are some disadvantages to gravity toilets. They use quite a bit of water, which can become a problem if you are boondocking and need to ration your overall water supply. The black tank also needs to be emptied at a proper waste station – which again, could be hard to find when boondocking – and that some people find a very unpleasant task (although, we have to say, it isn’t as bad as you might think if you’ve never done it before.)

Composting and Cassette RV Toilets

RV Cassette Toilets

Camco 5.3-Gallon Portable Travel Toilet - Features Detachable Holding Tank w/Sealing Slide Valve & Bellow-Type Flush - Easy Transport w/Compact Lightweight Design & Carry Handle (41541)

For these reasons and more, some people do choose to switch out their gravity flush toilet for a different option. Those who want to be more eco-friendly might opt for a composting toilet, and a very European option, the cassette toilet, is becoming more popular in the US as well.

View the Camco RV cassette toilet on Amazon

RV Composting Toilet

Nature's Head Self Contained Composting Toilet with Close Quarters Spider Handle Design

Composting toilets are exactly what they sound like – they compost waste – and cassette toilets work in the same way as a gravity flush toilet, but waste is stored in a removable, disposable cassette.

Check out Nature’s Head RV composting toilet on Amazon

Both have their downsides, including, in many cases, the need to re-do the plumbing in your RV bathroom, which, if approached as a DIY task, calls for plenty of patience and plumbing skill, and won’t be a cheap undertaking if you choose to have a pro do the job.

RV Toilet FAQs

Can I Flush an RV Toilet Without Water?

A standard gravity flush RV toilet, or a cassette alternative, should always be flushed with water. A composting toilet, much like a portapotty, does not make use of water as it does not flush in a traditional sense, instead waste is separated into solids and liquids and special RV toilet chemicals break the waste down.

While composting toilets sound like a great idea, if they are not meticulously maintained they can become very unpleasant to use very quickly, and, to be blunt, can stink up your RV fast too. However, if you are willing to put in the work (and all the right chemicals) they may be worth considering, if water conservation while camping is important to you.

Is RV Toilet Paper Necessary?

Close Up Of Toilet Paper Holder In RV Motorhome With Shower In Background
Typically, you don't want to use just any old residential toilet paper in your RV.

If you are new to RVing and are stocking up for your trip, you may have seen RV toilet paper and wondered if you really need to buy it specifically, especially as it is usually more expensive than standard household toilet paper. The answer is, unless you are using a composting toilet, which most people are not, the sensible answer is yes.

Although you will occasionally find an experienced RVer who says they use standard household toilet paper with no problem, you might want to take that with a grain of salt. Toilet paper designed for RV use degrades far faster than toilet paper designed for residential use. Regular toilet paper can accumulate in the depths of your black tank, trapping odors and attracting flies and other insects. That’s terrible, and it’s a pest problem that may eventually involve hiring pricey expert help to solve.

But that’s not all that can go wrong when you use the wrong toilet paper. If the wads of standard toilet paper become trapped in the hose connecting to the septic system, it can create a backup and prevent waste from passing efficiently into the septic system. This, too, can result in an unpleasant odor, insects, and a blocked black tank.

Scott Rapid-Dissolving Toilet Paper, 48 Double Rolls, Sustainable, Septic-Safe, Toilet Paper

Once you realize all this is possible, RV toilet paper does not seem like such a bad investment after all. And it’s not as expensive or hard to find as you might think. 48 double rolls of Scotch Rapid Dissolving Toilet Tissue for RVs which should last you through lots of camping trips – can be purchased for less than $35 on Amazon!

Check out Scotch Rapid on Amazon

What Can You Flush in an RV Toilet?

The only things that should ever be flushed in an RV toilet are what they are designed for: human waste and RV toilet paper. Anything else – disposable diapers, feminine hygiene products, general garbage – should be bagged and disposed of in the trash.

How Do You Use an RV Toilet?

No matter what type of RV toilet you have in your RV, using it is very like using the toilet anywhere else. Some are lower, and are flushed with a foot pedal rather than the standard side mounted flush you might be used to, but the good news is that they are not too ‘weird’ to use!

When To Replace Your RV Toilet

If they are well maintained, a standard RV gravity flush toilet should last for many years. As we mentioned earlier, the flap may become less efficient over time, but replacing that does not mean you have to replace the whole RV toilet.

You might also consider, as we mentioned earlier, switching out your standard gravity flush toilet for a composting or cassette model. While these can be purchased fairly easily, you should ensure you understand the work that the switch will call for, and, if you are going to try to do-it-yourself, you are confident that you can, or you may end up without an RV toilet for a while, and no keen camper wants that!

How To Keep Your RV Toilet Clean to Prevent Smells

An RV is a fairly small, relatively closed environment, and a smelly RV toilet is the last thing you need. Here are some of the best ways to keep your RV toilet clean and sanitary and your RV bathroom smelling fresh!

RV owner emptying black tank, adding RV holding tank deodorizer to camper toilet cassette at a dumping station for campers

1. Make Sure the Toilet Flap Closes Securely

If the toilet flap – the piece that opens and closes when you flush – is not securely closed, odors from the holding tank below can become a problem. Occasionally, as they age, these flaps may stop closely properly, at which point they may need to be replaced. This can also happen if you don’t flush properly, so try to get into the habit of checking that the flap is closed after every toilet use.

2. Keep the Toilet Clean

Thetford - 96009 Aqua-Foam - Cleaner for Porcelain and Plastic Toilets - 3x2 oz Pack 96010

No one likes cleaning toilets, but in an RV it’s especially important that you do, and that you do so often. One easy way to cut down on the number of times you’ll need to do a deep clean, keep a spray bottle filled with a mixture of water and a few drops of a nicely scented cleaner near the toilet, and spritz it into the bowl before you flush. You can also now purchase scented drop in and even foaming toilet cleaners that are specially formulated for use in RV toilets.

3. Keep the Black Tank Clean

Walex Bio-Pak RV Marine Natural Enzyme Black Holding Tank Deodorizer Drop-Ins, Camper, Boat, Camping Cassette Toilet Pods, Alpine Fresh, 10 Pack

It is just as important to keep your black water tank smelling fresh. Ensure that you make use of the chemicals your tank’s instructions advise, and that you empty the tank on a regular basis, hosing it out after you do. Adding holding tank safe deodorizers between clean outs can help too.


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