What is a Vault Toilet? How does it Work?

Last Updated on May 18, 2022 by toilethaven

What is a Vault Toilet?

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 work force? 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/or sewer lines to temporarily hold human waste. The vaults are either made of concrete or plastic. They are mostly constructed in parks and campgrounds, and are pumped when they are 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 bad 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 or 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 and when the pit is full it is abandoned and the waste left to decompose.

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

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

How does a Vault Toilet Work?


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

These are the toilets of choice in camping sites and recreational parks in remote areas. They are able to 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 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 vaults cubicles consists of a fiberglass riser mounted on a hole on the floor and a toilet seat with a lid on top of the riser. To prevent bad odor in the cubicle, you should always put the lid down when the toilet is not in use. You should also close the door all the time when the toilet is not in use.

Do Vault Toilets Smell?

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

A properly built, vented and cleaned vault toilet should not smell. Bad odors in vault toilets are as a result of 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.
  • 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 .
  • If dense forest vegetation will interfere with airflow, install a fan in the vent stack.

Are Sweet Smelling Toilets Completely Odor-free?

The sweet smelling toilets however, although successfully 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 at all?  Wind is the medium that sweeps away bad odors and brings fresh air. It goes without saying that 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 temperature conditions of the area. We know hot air rises. In 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 then climb up the vent stack and are therefore be expelled from the unit. This system can therefore not work effectively in cloudy or cold locations.

Vault Toilets vs Pit Toilets

A pit toilet or a pit latrine consists of a hole dug in the ground 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 of the organic matter will decompose while the liquids will seep into the ground below.

Both vault toilets and pit latrines have their own 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 just abandon it.

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

Vault toilets are however good when dealing with a big crowd like the one in a camping ground. If you decide to go with pit latrines it means 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 with the requirements of the Americans with Disabilities Act (ADA) while pit latrines don’t. These makes them the preferred toilets for use by the public in remote areas.

If the campsite is however in a very remote areas which can only be accessed by foot, pit latrines is 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, although not all people see it that way.

A vault toilet unlike a composting toilet does not have an end product in sight. As a matter of fact after the waste is pumped out, it is taken to the municipal sewage treatment facility.

Composting toilet are not designed to be used by a large group of people. Bad odor can build up pretty badly. As fewer people as possible 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

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

Although both 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 out 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 tank have no bad odors unless when full without the owners knowledge. They then start to back up through the toilet or any other fixture in the house.

Vault Toilets vs Porta Potty


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

Portable camping toilets have a bowl, a toilet seat, fresh water 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 which makes them unsuitable for a large group of people.

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

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 any water to flush.

Advantages of Vault Toilets

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

1. Cost effective

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

Imagine if you were working with a big workforce in a remote area but only for a short period of time. Without the possibility of vault toilets, you would have to spend a lot of money with 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 in the world use a flush toilet once every day. That is a lot of water used in a year with great detriment to the environment.

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

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

In areas where the water table is very close to the surface of the earth, 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, this are the rules that must be followed. They are intended to bring about order and standards in the sector. This is in line with the United States Forest Services vault toilet design principles.

  1. There shall be one vault for every one toilet riser.
  2. The vault shall have a black interior. This is designed to help the user of the toilet. If you lift the lid of the toilet, you can see the contents of the vault which can be gross.
  3. All interior vault surfaces shall be sealed. This is meant to avoiding 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 to the rear or side of the building. The manhole must have an air-tight seal and raised with concrete.
  6. Size of vault is determined by the number of users 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 vaults content through the riser.

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

It is important to have enough rules to regulate these important structures. While they offer convenience to users, vault toilet 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 fresh return of air. Apart from louvers dust off the windows, walls including removing any cobwebs and insect nests.
  3. Mix a deodorant, detergent and disinfectant (3D) in one side of a double bucket and clear water on the other side. Use the mixture and an abrasive brush to scrub walls and remove all the stains if any. Rinse with the clear water.
  4. Mop the floor as frequent 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 that legislation has been effected to make sure that their use and design is controlled to avoid abuse. I believe vault toilets are here to stay.