Project Abstract

Considering the current drought, composting toilets are likely to be part of the future for urban waste management. Not only does this technology conserve the earth's resources but it can also strengthen local food systems as the health of the soil in urban environments can be restored. Composting toilets are decentralized, use no water, and create a valuable fertilizer. In all, they may provide a more sustainable approach to the current sanitation infrastructure. Unfortunately, there are many barriers to the use of composting toilets in urban settings including regulations, preexisting infrastructure, and societal acceptance. It will be necessary to overcome these barriers before composting toilets can take be implemented in developed cities such as San Diego. Luckily many of these barriers can be overcome through communication - clearly written regulations, collaboration with other communities and countries that have already established composting toilet infrastructures, and education on the science and safety behind the technology.

Significance of Research

The state of California is currently facing the worst drought in modern history. The impact that the drought has made on California’s major water sources has added complexity to San Diego County’s water conservation efforts. San Diego imports about 80%  of its water – 30% from the Bay-Delta and 50% from the Colorado River. The Water Authority Board has created a Water Shortage and Drought Response Plan focused mainly on ways “to avoid rationing through supply enhancement”. The problem however is not in supply but in demand – as a society, water use distribution has shown that we have become accustom to expecting an unlimited supply of water. Even Governor Jerry Brown’s historical legislation on water conservation only provides a “framework” for water management and lacks action and specificity. Instead of finding new sources, cities should look at how they can cut back. Of indoor residential water use, San Diego toilets are responsible for 27%. According to the Environmental Protection Agency (EPA) "standard toilets use 1.6 gallons [of water] per flush, while older toilets can use as much as 3.5 to 7 gallons per flush". If all toilets in San Diego were replaced by dry composting toilets, this would mean a 7.2% reduction in water usage. A 7.2% reduction in water usage would be equivalent to 10.268 fewer gallons per person per day. 


  1. Raise awareness about the existence and use of composting toilets.
  2. Identify the barriers to implementing composting toilets in the urban context, specifically in San Diego.
  3. Explore the ways in which composting toilets can aid in creating alternative food systems in the city context.

Major Findings and Contributions

  • Considering the current drought as well as the potential for ecological and soil improvement, composting toilets may provide a more sustainable approach to the current urban sanitation infrastructure.
  • Most of the barriers to implementing composting toilets in the urban context can be overcome through communication:
    • By establishing a common language by which to discuss regulations, action can be taken to begin installation
    • By communicating the problems with the current wastewater treatment
    • By educating the public about the science behind composting toilets public acceptance can be gained.
  • San Diego has experimented with dry composting toilets at Lake Marina County Park.
    • People are complex, independent, and uncontrollable. Education is necessary to ensure that people would use the toilets correctly and not throw trash and other undesirables into the system.
  • The lack of formal regulations would creates a very delicate situation for the first introduction of composting toilets. If the first urban composting toilet trials do not work well, the acceptance of the technology could be set back by decades by public health officials.

Theory of Change

Since we all take park in consuming resources and generating waste, it is our social responsibility to take action. Composting toilets help to repurpose waste and instead create nutrients. Although current systems seem convenient, they are unsustainable. In all aspects of society we need to image alternative systems that are close-looped.

A prime place to start, at least in San Diego, is in community gardens: the installation of composting toilets is allowed, there is no preexisting infrastructure, and it is easier to gain public acceptance when the toilet is not within the home. This communal space can be used to ease the public into the idea of composting toilets in the urban context. 

"We cannot solve our problems with the same thinking we used when we created them."
- Albert Einstein