A vault toilet is a non-flush waterless toilet system installed in remote locations that don’t have access to a municipal sewer system. A vault toilet is a type of pit toilet where human waste deposits underground.
You may have run into vaulted toilets at forest service campgrounds. Most park services use privacy vault toilets. These are single units and are for only one person to use at a time.
Most vault toilets have a filled hand sanitizer dispenser in the unit. Some have sinks with running water.
How Does a Vault Toilet Work?
- Waste is deposited into a reinforced, sealed underground tank, typically made of concrete or cross-linked polyethylene plastic.
- A toilet riser and seat are installed above the vault, allowing direct waste collection.
- A venting system helps control odors by directing gases outside through a properly placed 12-inch vent pipe, which extends at least 3 feet above the roof.
- Vault toilets require regular pumping, to remove waste and maintain sanitation.
What are Vault Toilets Made From?
- Plastic Vaults (Cross-Linked Polyethylene): Lightweight, durable, resistant to temperature swings, and ideal for portable setups.
- Concrete Vaults: More permanent, highly durable, and used for long-term installations in high-traffic areas.
How to Remove Waste from Vault Toilet
- Waste is removed via an external, sealed manhole to prevent contamination and odors.
- Professional waste removal services pump the tank and transport sewage to treatment facilities.
- Adding 10 inches of fresh water after pumping helps prevent waste buildup and odor.
- Bacterial additives (like those used in septic tanks) can assist in waste breakdown and odor control.
Tips For Using a Vault Toilet
Put toilet paper into the vault toilet and do not use it as a trash can. If there are no trash services available, the trash leaves with you. You will help with park maintenance by keeping the vault toilets free from plugs and keeping our public spots clean.
Be wary of doors that don’t lock when using vault toilets in public spots.
Do not throw wet wipes into the vault toilet unless marked as safe to flush.
The Forest Service has been using vault toilets for decades. They do a good job of keeping vault toilets clean and stocked. Park services use one-ply toilet paper and low-grade sanitizer so bring your own if you want better quality products.
Pit Toilets vs. Vault Toilets
Although pit toilets are similar to vault toilets, there are some notable differences.
A pit toilet, also known as a pit latrine, uses a hole in the ground as a vault toilet does. However, the waste from a vault toilet is deposited into a concrete tank, whereas the waste from a pit toilet is deposited into an unlined hole beneath the soil.
If your waste situation is minimal, then a pit toilet is better than a vaulted toilet. A single person or small family might dig a pit latrine for temporary use while building a proper bathroom facility.
Vault toilets can accommodate a large volume of waste, but it’s toxic to the environment and cannot accumulate in an open pit like waste from pit latrines.
The waste from a pit toilet will decompose into the earth over time and therefore does not need emptying. Because of this, it is difficult to keep flies away from pit latrines.
The lifespan of a pit toilet is about five years, as the hole fills with waste over time. After that, you can move your pit toilet to a new location. Make sure to fill the old pit with soil to protect the environment.
Pit toilets can be stinky as the waste begins to decompose. You can counteract a stinky pit toilet by adding lye to the waste. Proper ventilation also helps.
Pit toilets serve best as a temporary situation, whereas vault toilets are permanent with proper servicing and maintenance.
Do Vault Toilets Smell?
Most vault toilets move smells away from the building. Smells are removed through the vent pipe as hot air rises up and out.
However, hot air has a harder time escaping during cold and damp days. And that is when vault toilets begin to stink.
How to Reduce Odors
- Proper Ventilation – Ensure the vent pipe is correctly placed on the windward side to optimize airflow.
- Bacterial Additives – Use natural biodegrading bacteria (similar to septic tank treatments) to break down waste and reduce odors.
- Activated Carbon – Sprinkling activated carbon into the waste helps absorb and neutralize gases.
- Preloading with Water – Maintaining 10 inches of water in the vault prevents solid waste from piling up and releasing strong odors.
- Long Vent Pipes – Extending the vent stack or running underground pipes away from the building can help redirect odors.
- Sun-Assisted Venting – Painting the vent pipe black or enclosing it in a metal shroud can use solar heat to create a natural convection effect, improving odor removal.
Pros and Cons of a Vault Toilet
If you are thinking about installing a vault toilet on your property, consider these pros and cons first.
Pros:
- No Groundwater Contamination – Unlike pit toilets, vault toilets have a sealed tank, preventing waste from leaching into the soil or water supply.
- Low Maintenance – Requires only periodic pumping (every 1,500 uses or once per season), unlike composting toilets that need frequent handling.
- Long-Term Placement – No need for relocation like traditional outhouses, making them a permanent waste solution.
- Odor Management – With proper ventilation (e.g., a 12-inch vent pipe placed 3 feet above the roofline), vault toilets can remain odor-free.
- Suitable for Cold Climates – Unlike some composting toilets, vault toilets do not require heat or electricity, making them ideal for off-grid and remote locations.
- Durable Materials – Constructed from reinforced concrete or cross-linked polyethylene plastic, vault toilets can withstand extreme temperatures and heavy use.
- Customizable for Capacity – Can be designed as single or double vault units, with sizes ranging from 750 to 10,000 gallons, depending on usage needs.
- Eco-Friendly Options – Adding bacterial treatments helps break down waste naturally, and solar-assisted venting improves airflow for odor control.
Cons:
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Requires Regular Pumping – A vault toilet must be pumped by a professional waste removal service, which can be costly and difficult in remote locations.
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Odor Issues in Poorly Designed Units – If ventilation is inadequate, gases can build up, especially in cold, damp conditions. Proper vent placement and maintenance are crucial.
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Winter Freezing Risk – In subzero temperatures, waste can freeze, potentially leading to a “frozen poo pyramid”. Preloading the vault with 10 inches of water can help prevent buildup.
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High Installation Costs – Vault toilets require excavation and a buried tank, making installation more expensive than a basic pit toilet. Concrete vaults are especially costly, though plastic vaults offer a more affordable alternative.
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No Waste Breakdown – Unlike composting toilets, waste does not decompose inside a vault toilet; it must be manually removed by pumping.
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Not Ideal for Heavy Daily Use – While great for seasonal or occasional use, a small vault toilet may fill up too quickly for permanent residential use without frequent pumping.
Different Types of Non-Flush Toilets
A non-flush toilet is ideal for homesteading, camping, and for those who want to help the environment by using less water and making less waste.
Vault toilets may not be the best solution for you. Several types of non-flushing toilets could suit your situation better.
Bag Toilets
These are waterless toilets that use bags for securing waste. Your waste goes into the bag, you press a button, and then the air is sucked out of the bag. The filled bag moves to the bottom of the toilet, and another takes its place. This process is all done through automation.
The filled bags are thrown out once the roll of bags has been used.
Bag toilets never stink because there is no air exposure. However, the bags used in this type of toilet is not biodegradable. There are better solutions where waste can break down and not sit in a landfill.
Composting Toilet
Composting toilets are waterless toilets that use peat moss, pine shavings, or other organic materials that the waste deposits into.
The toilet has a chamber that spins, mixing the waste with the organic material. As a result, the waste begins to break down into compost that is usable in your garden.
Prefabricated composting toilets are expensive, costing an average of $1,500. But you can build one yourself out of lumber. However, a prefab composting toilet has a nice sleek design that is easy to maintain and blends in with modern bathrooms.
Porta-Potties
Porta potties are movable temporary toilets commonly found at festivals and big events. Although they use some water, porta-potties don’t flush and are efficient for a large amount of traffic.
Depending on usage, porta-potties need frequent emptying, from once a day to once a week. If emptied on a schedule, porta-potties don’t stink much as the companies pour a strong antibacterial liquid into the water.
You can use a porta-potty as a temporary solution while building on your property. You will need to hire a company to haul the toilet to you, empty it on a schedule, and then haul it away when you no longer need it anymore.
