How Do Porta-Potties Work?

How Do Porta Potties Work

Whether you’re in the midst of a home remodel or part of the throngs enjoying an outdoor festival, you may find yourself in a situation where there is no convenient bathroom nearby. What are you to do?

Hopefully, someone thought of this issue ahead of time and invested in a porta-potty and the idea of a portable potty rental. But, once you experience the relief of finding a porta-potty (and the relief of using the porta-potty), have you ever wondered, “how do porta-potties work?” This guide will go over the details, from how a porta-potty differs from a regular toilet to where the waste goes at the end of the day (and how it gets there). 

Porta-Potties vs. Flush Toilets

To understand how a porta-potty works as a toilet option, it helps to first understand how the regular toilet in your house works. In short, the flush toilet in your house and restroom works by using a lot of clean water to flush your waste out of your house and into a sewage system. Let’s take a simplified look at this process:1

  • Your toilet is hooked up to a supply line that provides water to the tank.
  • The tank holds around two gallons of water (depending on the flush capacity of your toilet) at all times.
  • When you flush the toilet, a device called a flapper opens, allowing the fresh water to rush from the tank into the toilet bowl.
  • This excess of water in the bowl creates a pressure difference that pulls everything from the bowl of the toilet into an outlet pipe. This pressure is the force that allows your toilet to empty when you flush.2
  • Once the process is completed, the supply line refills your tank until the water returns to a level allowing another flush.

This is a very basic explanation. You can go much more in-depth to learn how siphoning pressure works, how the overflow tube and inlet valve regulate the amount of water, and where the waste goes after you flush, but we’re here to talk about how portable toilets work.

Porta-potties are simpler than your home toilet seat. Since there is no plumbing to connect them to, they don’t have a refilling tank that can utilize siphoning pressure to remove human waste, and liquid or solid waste. Instead, porta-potties utilize a waste holding tank filled with different chemicals where your waste is stored until it can be removed and disposed of. 

Basically, you use the porta-potty and your waste is held in the tank until someone comes later to vacuum it up and get rid of it.

What Are the Chemicals in a Porta-Potty?

Depending on how many people use a porta-potty between cleaning, that holding tank can start to fill with a lot of human waste and start releasing a bad odor. If it weren’t for the chemicals used in the holding tank, that could result in more than just a nasty smell. That much waste can start to cause a dangerous build-up of bacteria. 

To avoid this, most porta-potties use a blue liquid in the tank. This liquid consists of multiple elements to help remove any bad odor:3

  • Blue dye – Why is the liquid blue? The darker blue color is used to disguise the contents of the holding tank so you can’t see what’s in there. Even with the blue color, you probably don’t want to take a close look.
  • Fragrance – By adding fragrance into the holding tank, some of the natural odors are neutralized. Most porta-potties will also come equipped with a vent to allow air to circulate and smells to become more diffuse.
  • Biocides – These are the chemicals used to kill bacteria. In the past, formaldehyde was the preferred chemical for this purpose but things have changed. Since formaldehyde is a carcinogen, porta-potties no longer use it, now favoring biological additives like odor and bacteria-killing enzymes. These enzymes are effective and far better for you and the environment than formaldehyde.

Variations to Deal with Temperature

Porta-potties need to function in a wide variety of different temperatures to maintain themselves as a sufficient portable bathroom. To help with this, some things may need to be added to the holding tank so it will function better in the elements:

  • Heat – Excess heat won’t create the need for any other chemicals. It will simply require more of them. Because heat adds to bacterial growth (and to smell), there will be a higher concentration of fragrance and biocides in the mixture.
  • Cold – You really don’t want your blue liquid or any of the waste in it to freeze in cold temperatures. In situations where the porta-potties need to function in the cold, salt will be added to the mixture, lowering the freezing point and ensuring it works as intended.


How Do You Empty a Porta-Potty?

Do you know how to empty a porta-potty? If not, we’ve got you covered. Since porta-potties rely on holding tanks to store human waste, there’s only so long the tanks can go before they become too full and need to be emptied. You can expect most standard porta-potties to last for around 200 uses before they need to be emptied and cleaned.

So how does the cleaning process work? You’ll need a few things:

  • A truck equipped with its own storage tank
  • A vacuum hose connected to the truck
  • A team of one or more sanitation workers

Once you have those three elements, the process is pretty straightforward. The worker uses the hose to vacuum up the contents of the porta-potty holding tank into the truck. The truck then transports the waste to a wastewater treatment plant.

In addition to vacuuming the contents of the tank, the sanitation worker will also clean the interior of the porta-potty itself. Once this task is complete, a new batch of chemical liquid will be added to the holding tank, and the porta-potty will be ready for another 200 uses before the cleaning process needs to be completed again.

Where Are Porta-Potties Used?

When considering where you might need a porta-potty, the answer can be summed up pretty easily: Anywhere that people will need to use the bathroom and flush toilets are not available or sufficient.

Perhaps you’re hosting a large event and the number of bathrooms will not accommodate the number of guests. Perhaps you’re in a place where no plumbing is available. People will still need a toilet and you don’t want to be caught without one.

As far as where you’re most likely to find porta-potties, there are many scenarios:

  • Work sites where there are no other bathrooms.
  • Large events like sporting events or outdoor concerts that don’t have nearby facilities that can accommodate the attendees.
  • Recreation areas like parks or campgrounds.
  • Agricultural fields to accommodate large numbers of outdoor workers.
  • As part of an emergency response where people need to be relocated into temporary shelters.
  • Permanent options for people housed in areas that do not have access to plumbing.

Types of Porta-Potties

The standard porta-potty can be pretty basic. Shaped like a large box, it will likely include:

  • A toilet seat and a lid
  • Toilet paper
  • A vent
  • A lockable door

This covers the basic needs, but there are numerous types of porta-potties that come with more features:

  • Sink – Many porta-potties can be equipped with a working sink and soap dispenser so you don’t need a separate hand-washing station. However, having hand sanitizer in any portable bathroom is always a plus.
  • Flushable – “Flush” may be a slight misnomer. These units don’t flush like your home toilet. Instead, the holding tank is closed off, hiding unwanted sights and smells. A foot pedal controls the flushing mechanism that opens the tank after you’ve done your business
  • Handicap accessible – Porta-potties can often be a tight squeeze. This smaller size helps make them transportable and keeps the costs down, but they don’t work for everyone. Larger-sized options are available to accommodate wheelchair users or anyone who may have reason to need the extra space.
  • Baby-changing stations – Some porta-potties can come equipped with fold-down tables to aid families if they need to change their baby’s diaper. These can be particularly useful for any large, family-friendly events.

Beyond these, there are also customizable options available so you can make sure to get the perfect portable toilets to suit your needs.

Can a Porta-Potty Tip Over?

Finally, let’s address the question we all have but don’t want to ask: Is the porta-potty going to flip over while I’m inside?

Almost certainly not.

The reality is porta-potties can flip over, but they are designed not to. It would take a large amount of external force to flip over a porta-potty, and that force would need to be even greater when you add the weight of a human into the equation. So, if you find yourself in a hurricane, you may want to hold out for another porta-potty rental option. Otherwise, you should be perfectly safe in a porta-potty.

All Your Porta-Potty Needs at ASAP Site Services

If you’re going to be in a situation where plumbing won’t be accessible, then you need a porta-potty. And if you need a porta-potty, we have you covered at ASAP Site Services.

We can handle all your porta-potty needs. We provide multiple types of porta-potties as well as hand washing and shower stations. And we’ll set up a schedule with you to make sure your units are emptied and cleaned as often as needed. 

If you have other questions aside from porta-potty hygiene, like knowing how many porta-potties per person you’ll need for an event or construction site, we’re here to help answer those, too! Contact us today.


  1. Explain That Stuff. How toilets work. 
  2. Lee Knight, MIT. Toilets.
  3. How Stuff Works. How Porta-Potties Work.  
  4. Portable Sanitation Association International. Types of Units. 
  5. Portable Sanitation Association International. About the Portable Sanitation Industry.  
  6. Portable Sanitation Association International. SPECIAL EVENT CHART. 
  7. Mental Floss. How Are Porta Potties Cleaned? 
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