What is a Vault Toilet? How Does it Work?

Last Updated on July 27, 2023 by toilethaven

Imagine a company with 200 employees has won a mining contract in a remote area without running water and sewer lines. What will the management do to provide proper sanitation to its workforce? A vault toilet!

A vault toilet is a non-flush toilet put up on an underground tank (vault) built in an area without running water and sewer lines to hold human waste temporarily. The vaults are either made of concrete or plastic. They are mostly constructed in parks and campgrounds and pumped when full.

Most vaults hold between 750 and 1000 gallons of waste, although bigger ones of up to 13000 gallons are available. They are normally vented to discharge foul odors and are also accessible when the waste needs to be pumped out.

Vault toilets are mostly built in camping grounds located in remote places. Although campers often have porta potties, vault toilets have a bigger capacity and are also excellent places to empty the camping toilets.

Most people often confuse vault toilets and pit latrines, known as pit toilets. So, what is the difference between the two?

The difference between a vault toilet and a pit toilet is that in a vault toilet, the waste is temporarily stored in an underground tank, where it is pumped out when full. In a pit toilet, there is no underground tank; when the pit is full, it is abandoned, and the waste is left to decompose.

Vault toilets have the potential to smell, especially when they are not properly constructed and maintained. However, vault toilets constructed as recommended and when properly maintained will not smell, hence the name “sweet-smelling toilets.”

Ideally, vault toilets should have toilet paper, and most actually have it. That, however, does not always happen. This being public toilets, toilet paper runs out fast, and you are not always guaranteed to find toilet paper in a vault toilet.

How Does a Vault Toilet Work?

How Does a Vault Toilet Work

A vault toilet works by allowing human waste to be temporarily held in the vault in an area without running water or sewer lines and without harming the environment.

These are the toilets of choice in camping sites and recreational parks in remote areas. They can offer privacy and are cheap to clean and maintain.

Apart from just feces and urine, other organic wastes are also emptied inside the vault, which is vital in ensuring the cleanliness of the camp. Waste that cannot undergo decomposition should never be put inside the vault. Water from shower cubicles is also directly inside the vault.

Vault toilets are put up in areas with good access roads. This is to allow sewage-pumping trucks to make their way to the vaults. If this is not possible, the porta potties or pit latrines should be considered.

The vault cubicles consist of a fiberglass riser mounted on a hole in the floor and a toilet seat with a lid on top of the riser. To prevent foul odor in the cubicle, always put the lid down when the toilet is not in use. You should also always close the door when the toilet is not in use.

Do Vault Toilets Smell?

Do Vault Toilets Smell

The biggest talking point about vault toilets is bad odor. It even got the United States Forest Service concerned that they came up with regulations to control how these toilets should be built.

A properly built, vented, and cleaned vault toilet should not smell. Bad odors in vault toilets result from ammonia and gases from the anaerobic decomposition of the fecal matter, as well as other organic substances like foods and drinks dumped in the vaults.

The United States Forest Service, in an attempt to curb the vault toilets’ odors, came up with requirements that should be complied with while vault toilets are being constructed. They are called the “Sweet Smelling Toilets” standards

In order to have a sweet-smelling toilet, observe the following:

  • Locate the vent on the side of the building facing the prevailing wind.
  • The door should remain closed at all times.
  • Low-growing trees and shrubs located within the critical airflow zone (radius of 20 feet from the building) are welcome as long as their height does not exceed that of the building.
  • Install a fan in the vent stack if dense forest vegetation interferes with airflow.

Are Sweet Smelling Toilets Completely Odor-free?

The sweet-smelling toilets, however, although successful in many ways, did not take off as originally intended. Mother Nature still found a way of pouring cold water on the feet of the US Forest Service’s efforts.

What happens if the vault toilet is constructed in an area with no wind? The wind is the medium that sweeps away bad odors and brings fresh air. The entire surroundings will not have the same smell as a farm of roses.

The success of a sweet-smelling vault toilet will also depend on the temperature conditions of the area. We know hot air rises. On a sunny day, the air in the vent stack will be heated and exit the stack into the atmosphere.

Since a vacuum cannot exist in the vent, the bad-smelling gases will climb up the vent stack and be expelled from the unit. This system can, therefore, not work effectively in cloudy or cold locations.

Vault Toilets Vs. Pit Toilets

Vault Toilets Vs. Pit Toilets

A pit toilet or a pit latrine consists of a hole dug in the ground and then covered using wood, brick, or concrete with a drop hole in the middle. Some have walls and a roof. Fecal matter and urine are dropped from the drop hole. Most pit toilet users normally squat, but some toilets have risers with seats installed on top of the drop hole.

The major difference between a pit latrine and a vault toilet is that waste in a vault toilet is pumped out after some time, while the waste in a pit latrine is never pumped out. Most organic matter will decompose while the liquids will seep into the ground below.

Both vault toilets and pit latrines have their advantages and disadvantages. Pit latrines are easy and cheap to put up since a vault is not needed, and you also don’t need to empty them. When one is full, you abandon it.

Due to the fact that waste in a pit latrine is in direct contact with the earth, decomposition takes place quickly, minimizing odors. In a vault toilet, the waste that exists as a slurry needs deliberate efforts to keep odors at bay. It is especially worse when being pumped out.

Vault toilets are good when dealing with a big crowd like the one in a camping ground. If you decide to go with pit latrines, you will have to keep digging latrines all over the facility, which is far from ideal and also not very eco-friendly.

Vault toilets also adhere to the requirements of the Americans with Disabilities Act (ADA), while pit latrines don’t. This makes them the preferred toilets for use by the public in remote areas.

If the campsite is, however, in very remote areas which can only be accessed on foot, pit latrines are the way to go. Otherwise, there would be no way of pumping out the vault toilets.

Vault Toilets Vs. Composting Toilets

A composting toilet is a waterless toilet that treats human waste through organic decomposition to form a compost matter that can be reused. A compost toilet has an end product in sight; therefore, not all people see it that way.

Unlike a composting toilet, a vault toilet does not have an end product in sight. After the waste is pumped out, it is taken to the municipal sewage treatment facility.

Composting toilets are not designed to be used by a large group of people. A foul odor can build up pretty severely. Fewer people are ideal so that the waste can have time to decompose.

There are 2 types of composting toilets. Permanent and portable composting toilets. Portable composting toilets can also be used as camping toilets or in RVs.

Check out some of the best composting toilets here.

Vault Toilets Vs. Septic Tank

Vault Toilets Vs. Septic Tank

A septic tank is an underground water-tight container usually made of concrete, polyethylene, or fiberglass where domestic wastewater flows for basic treatment. Solids, liquids, and scum are separated here.

Although vault toilets and septic tanks are placed underground and are water-tight, they are very different.

A vault toilet is constructed where there is no running water, while a septic tank is made where there is plenty of water. Septic tanks are also constructed on people’s homes and have no structure on top.

In a septic system, the liquid waste is separated from the solid waste inside the septic tank. The liquid flows through a series of pipes and seeps through the ground.

The solid organic matter is acted on by the bacteria inside the septic tank and settles at the bottoms of the tank. Soap scum, fats, and grease settle at the very top of the tank.

Septic tanks have no bad odors unless full without the owner’s knowledge. They then back up through the toilet or any other fixture in the house.

Vault Toilets Vs. Porta Potty

 Porta Potty

There are 2 types of porta-potties. One is a cubicle form where you enter and do your business as you would in a typical bathroom. The other one is portable camping toilets.

Portable camping toilets have a bowl, a toilet seat, a freshwater tank, and a holding tank. The holding tank is usually not more than 5.5 gallons making them a good choice for not more than a few people.

Non-portable porta potties have a bigger holding tank than portable toilets but way less than vault toilets. They need to be emptied frequently.

The main difference between porta potties and vault toilets is that porta potties are flush toilets while vault toilets are not. They also have a smaller holding tank, making them unsuitable for many people.

While vault toilets are properly vented and built in areas with good air movement, porta potties have no vent stack; therefore, odor management is difficult.

Instead of having many porta potties lined up, a vault toilet system makes more sense. They (vault toilets) are also dry toilets and do not need water to flush.

Advantages of Vault Toilets

The following are the advantages of installing a vault toilet over toilet alternatives in remote locations.

1. Cost effective

Vault toilets allow you to install a good sanitation facility at a fraction of the cost you would have otherwise used to install modern toilet facilities.

Imagine working with a big workforce in a remote area but only for a short period. Without the possibility of vault toilets, you would have to spend a lot of money on modern toilets, which would need to be abandoned after the job is done. Getting water for flushing toilets there would also be a nightmare.

2. They are convenient

Imagine a group of 20 people camping in a forested, remote location without the possibility of a vault toilet. Of course, there are no flush toilets in such areas.

Putting up vault toilets in such locations is easy and can be used for a long time. Without this option, it would be a sanitation disaster.

3. Eco-friendly

Just assume the 7 billion people worldwide use a flush toilet once every day. That is a lot of water used in a year with great environmental detriment.

Vault toilets do not require any water apart from that used during cleaning. Transporting water with trucks for flush toilets would be expensive and bad for the environment.

Unlike a pit latrine, a vault toilet is water-tight and does not allow water to seep into the ground.

In areas where the water table is very close to the earth’s surface, releasing raw human waste into the ground will for sure interfere with the natural ecosystem.

How to Build a Vault Toilet

While putting up vault toilets, these rules must be followed. They are intended to bring about order and standards in the sector. This aligns with the United States Forest Services vault toilet design principles.

  1. There shall be one vault for every toilet riser.
  2. The vault shall have a black interior. This is designed to help the user of the toilet. If you lift the toilet lid, you can see the vault’s contents, which can be gross.
  3. All interior vault surfaces shall be sealed. This is meant to avoid the leaking and absorption of gases by the material used to make the structure.
  4. The vault bottom shall have a 1-inch per feet slope towards the outside cleanup area. This will ensure that the waste is thoroughly removed.
  5. The vault shall have a minimum of a 24-inch manhole cover installed on the rear or side of the building. The manhole must have an air-tight seal and raise with concrete.
  6. The number of users determines the size of the vault at the time.
  7. The depth of the vault shall not be deeper than 5 feet.
  8. The vault toilet pumping contract shall not be allowed to pump out the vault’s content through the riser.

The design and construction of a vault toilet are controlled by many legal requirements, and the above are just a few.

It is important to have enough rules to regulate these important structures. While they offer convenience to users, vault toilets can be a nuisance to other people if not well controlled.

Vault Toilet Cleaning

These are the steps to follow to ensure that a vault toilet is properly cleaned. A clean vault toilet, apart from eliminating odors, will help to prevent diseases.

  1. Maintain a clean environment around the vault. Pick all the scrap paper on the trail to the vault and dispose appropriately. Never throw scrap papers in the vault. This increases the pumping difficulty.
  2. Dust off vent louvers to enable the fresh return of air. Apart from louvers, dust off the windows and walls, including removing cobwebs and insect nests.
  3. Mix a deodorant, detergent, and disinfectant (3D) on one side of a double bucket and clear water on the other. Use the mixture and an abrasive brush to scrub walls and remove all the stains, if any. Rinse with clear water.
  4. Mop the floor as frequently as possible with the 3D solution.
  5. Use a long-handled brush dipped in a 3D solution to clean the inside of the toilet riser. Apart from sanitary reasons, a clean rise also prevents bad odors.
  6. Check for toilet paper supply and replenish the vaults running low on this.

Suppression of vault toilet odors by chemical means is not encouraged. The chemicals have a negative effect on the sewage final treatment process.


Vault toilets are truly convenient and cost-effective sanitation structures, especially in areas with no access to piped water and sewer lines. One can only imagine what could happen without the possibility of operating them.

It is even better than legislation that has been effected to make sure that their use and design are controlled to avoid abuse. I believe vault toilets are here to stay.