What is a waterless toilet?

What is a waterless toilet?
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Waterless toilets, also known as dry toilets, typically utilize no water for flushing.

In these kinds of waste disposal systems, there is no water used for treating or transporting human excreta.

Waterless toilets lead to conservation of water and spare waterways and the environment from dangerous effluents released from the sewer treatment plants.

A waterless toilet, is a step up from the traditional pit latrine. Pit latrines, though convenient, often emit odor unlike waterless toilets.

Furthermore, the compost from waterless toilets can be used to produce nutrient-rich fertilizer, if the user treats it correctly.

The different kinds of waterless toilets

There are different types of waterless toilets, some of which are:

  • Composting toilets
  • The traditional out-house system
  • Chemical waterless toilets
  • Form flush toilets
  • Vacuum-flush toilets
  • Incinerating toilets
  • Evaporating toilets
  1. Composting toilets

Composting toilets are the most popular type of waterless toilets. In composting toilets, the waste is collected from the toilet bowl and channeled into a tank to be decomposed.

In the holding tank, an intricate biochemical interaction occurs that is affected by several factors, including PH and temperature.

A composting toilet must achieve the following objectives:

  • Capably evaporate the liquid from the human waste
  • Decompose the waste fast and without producing stench
  • Make sure the completed compost is devoid of harmful pathogens or viruses

Although the process of decomposing is similar to the garden composter, the efficiency of decomposing in a composting toilet is usually enhanced.

There are three main types of this kind of waterless toilets:

  • Continuous composting toilets
  • Batch composting toilets
  • Self-contained composting toilet

a) Continuous composting toilets

It is a single container toilet. The excrement decomposes as it moves through the receiving container, and comes out as compost at the end-product chamber. The container receiving the waste is located beneath a bathroom; normally found below the toilet seat.

The container does not have to be completely emptied, since the compost is slowly removed whenever it is at the end-product chamber.

The prime disadvantage of this type of composting system is that fresh waste and pathogens pile on waste that has already been decomposed.

In addition, it is also possible for waste to pile and avoid moving down into the container. Eventually, it gets compacted and can cause blockage. Due to the use of a single container, a problem with the toilet might mean no use of the system until the problem is resolved.

b) Batch composting toilets

Batch composting toilets have two or more containers, which are usually alternated. One container is used to collect waste from the toilet, while the waste on the other container is left to decompose.

In the batch system, the container filled with waste is switched with an empty one. The filled container is disconnected from the toilet seat or the toilet seat is moved to a different empty container.

Batch systems take up more space in the bathroom because of the different containers used.

c) Self-contained composting toilets

Self-contained composting toilets are suited for homes or buildings where installing a composting chamber below the floor is difficult.

The system consists of a fan, and a miniature heater that helps in the decomposition of waste.

  1. The traditional out-house system

In this anaerobic waterless toilet, the waste is left to be broken down by organisms such as flatworms and leeches. The breakdown results in release of sulfur, ammonia and methane.

A key disadvantage of this system is that exposed feces attract maggots and flies, which is very unhygienic.

  1. Chemical waterless toilets

This type of waterless toilets has small tanks. The tanks have considerable amount of liquid chemicals intended to kill pathogens and suppress smell.

They are suitable for short-term disposal of wastes. After a while, the tanks are emptied and the waste disposed to septic tanks or sewers.

  1. Form flush toilets

Foam flush is the kind of waterless toilet that utilizes a small amount of soapy foam to make the bowl slippery. Since the soapy foam makes the toilet bowl’s surface slippery, it enables the sliding of waste to the depositing tank.

  1. Other types of waterless toilets
  • Vacuum-flush toilets utilize air in sucking waste through tubes to a depository.
  • Incinerating toilets burn the waste to ashes. The burning produces no odor.
  • Evaporating toilets, on the other hand, dry, sterilize and evaporate waste.


Water is a precious resource that is increasingly becoming scarce around the globe. The use of water for flushing toilets is becoming something unrealistic in many water scarce countries, mainly due to the high costs in getting a regular supply of water.

Furthermore, there are competing uses of water, such as drinking and cooking, which are of greater importance.

Pit latrines are deemed a source of contamination for ground water which leaves them out of the equation. Septic tanks and bucket latrines are equally expensive to maintain.

Therefore, waterless toilets are the most practical and hygienic means of disposing human waste.