How Much Water Does An RV Toilet Use?

Water conservation is always a concern while camping in your motorhome or trailer. Whether you are trying to make your fresh water supply last longer or stretch the time between emptying your black tank, flushing water down your RV toilet drain feels wasteful.

RV toilets, on average, use 0.8 gallons (3 liters) per flush. Although it may seem wasteful, holding down the flushing peddle for ten seconds each time is a good practice. It helps ensure the flushing process is effective, and having sufficient water in the black tank acts as an odor barrier.

RV toilets are simple in comparison to home toilets and sewer systems. Unlike the home toilet, RV toilets are environmentally friendly and must function at their best to create a better experience for you while you are on holiday doing your business. 

Photo 181938405 © Welcomia |

Why Your RV Bathroom Smells

Despite what anyone else says, it is essential to use as much flushing water as possible in your RV  toilet. Each flush helps fill the black water tank, which is that unspoken part of the RV that no one talks about. Yet, because of the contents of the black water tank, it can play a massive part in how enjoyable your holiday is.

Water is a natural odor barrier, and if there is any part of the RV which needs a barrier from odors, it is the black water tank!! Ensuring enough water is flushed into the black water tank means that smells are contained, and the RV stays a pleasant place to live. I battled the bathroom smell for weeks before figuring out the connection to water and proper flushing.

If your RV bathroom is smell from excess moisture on the floor there may be problems with the toilet seal. Here’s my latest post on how to stop your RV toilet from leaking at the base

Water leaks and plumbing issues require expensive repairs to your RV. For less than the price of a single visit to your local RV maintenance facility, the Fix It Yourself RV maintenance video course shows you how to fix all the common issues and save 1000’s of dollars in repair bills.

Fix it Yourself RV Maintenance Course

What Is The Best Way To Use An RV Toilet?

Using an RV toilet may seem obvious but there are some procedures to follow, which will differ from your toilet at home, and which significantly improve your whole RV holiday experience.

Fill The Toilet Bowl Before Using It

Whatever you do, don’t use the toilet before you first fill the bowl. 

Remember your toilet at home always has water in the bowl. Even though flushing after the act rinses the bowl, the solid waste has already stuck to the dry toilet bowl, which means it will probably take more than a flush to get it off.

I usually press the pedal about halfway for a few seconds to add sufficient water to fill the bowl and help prevent any residue from sticking to the side of the bowl.

Likewise, after you have contemplated all the issues of the world and have finished doing your business, flush the RV toilet for another ten seconds. After all, the first prize is to not clean the toilet bowl while you are on your holiday, so use lots of water to fill the toilet bowl before you use it to avoid manual toilet cleaning as often as possible.

Saving Water While Flush An RV Toilet

Place two squares of toilet paper in the bowl before you use the toilet to help your solids flush more easily into the holding tank. With the water in the tank and the squares of toilet paper, the residue should not stick to the sides of the bowl.

Another way to save water is to ensure you’re not wasting it. Here’s my recent article on how to stop your RV toilet from running.

Don’t Flush Anything Else Down The Toilet.

Dealing with a blocked RV toilet is a great way to ruin a perfect day. 

Other than your waste and a small amount of toilet paper, do not flush anything else down the RV toilet. That means no cigarette buts, no feminine products, no facial tissues, no diapers, your kids, or your mother-in-law.

Keep Several Inches Of Toilet Water In The Bowl At All Times

Apart from when driving, it’s good to practice keeping a few inches of water in the RV toilet at all times. Remember earlier I said that water is an odor barrier, keeping a little water in the bottom of the bowl will prevent odors from seeping up around the flapper.

The design of your home toilet always keeps some water in the bowl so that no sewer gasses reverse their way up the pipe and into your bathroom system. The same applies to your RV toilet. The device is typically positioned over the black water tank, which is connected to the toilet’s outlet pipe. If there is no odor barrier, your RV could end up smelling like an abandoned outhouse.

Here are the details on Replacing an RV toilet with a standard house toilet

Your Black Water Tank

The best way to prevent blockages and odors in your black water tank is by using an eco friendly holding tank treatments that include high-quality aerobic bacteria. The digestive enzymes will control the smell and hurry the decomposition process. 

These bacteria must have ample water to survive and to cover all the waste, so although plentiful quantities of water in your black tank may feel wasteful, it will help prevent other issues from developing that could be much more annoying than making a few extra trips to empty the tank.

Without water soaking them, solid waste and toilet paper will dry up and pose a potential threat of blockages. If you always make sure that there is sufficient water in the black water tank, it will help keep the solids softer, and there will be less chance of a blockage.

Eco Strong RV Toilet Treatment | Black Holding Tank Deodorizer and Waste, Tissue, Sewage Digester -...
  • 33 Treatments: Bio-enzymatic Black & Gray Water Solid Digestor: Our professional-strength bio-enzymatic formula breaks down all organic...
  • Unmatched Odor Elimination: Some products contain biology, and some have only enzymes. Eco Strong is the only product powered by both. Our...
  • Waste Liquification, Odor Removal & Sensor Cleaning All in One Bottle: Our liquid formula delivers the most potent combination of...

Keep The Black Tank Valve Closed

Make sure your black tank valve is closed, even when connected to the sewer. It is critical to have a good quantity of liquid in the black tank when emptying it. Ultimately it will create the dreaded poop pyramid buildup in your black tank as the liquids drain leaving the solids behind.


Your RV waste disposal system is a very well-engineered way of handling a messy problem. Correctly operated, the system will prevent sewage odors, and you will have a wonderful time away.

Doing it wrong may result in an RV that smells something akin to a public toilet, and your RV experience will be forever blighted.

A good way to ensure that everything operates as it should is to use the toilet flushing system generously. A ten-second flush on either side of a bowel movement may use more water than is suggested in the marketing brochures, but it will help keep the movements flowing and odors at bay.


Beau is an electrical engineer with a knack for DIY repair and construction. When he's not tinkering with his projects he's on the road travelling and enjoying an exciting lifestyle with his young family.

Recent Posts