Winners of the 2012 “Reinvent the Toilet Challenge“, Caltech teamed up with plumbing manufacturer Kohler to develop a mobile restroom equipped with a solar-powered water-treatment system that could be used in areas without plumbing infrastructure.

Kohler was invited to collaborate on this project as the company has been around in the Indian markets for a while and has collaborated with several designers and architects. Kohler’s Indian team assisted in selecting locally available plumbing products and played an important role in the overall décor to ensure that local communities were more accepting of the new technology.  The biggest challenge was to establish a cultural context to the local environment.  After weeks of extensive research and design process, the exterior design was finalized. Kohler’s global creative director, Tristan Butterfield chose the traditional Indian truck art for the exterior design and Open Door Design Studio (ODDS) was brought on board to provide the design concepts.

“I started to work with them to specify the right products for project, knowing they’re trying to build sealed toilet solution prototype to be shipped to India on the 17th of December.”  explains Butterfield. The mobile restroom had to be placed inside a container to showcase at the “Reinvent the Toilet Fair” in New Delhi, India. Butterfield adds, “The fact is that this thing is going to be put into a community in India and someone is going to have to live with that.”

The exterior colourful artwork comprising of  flowers, birds, animals and scenery – all inspired by the truck art of India.

“The research process required us to select motifs and messages that would propagate the significance of water conservation and environment sustainability — concepts that formed the essence of the project, while capturing the stylistic quality of the truck art. Illustrations of Sun, girls worshipping the Sun, oils lamps and introduction of solar panels in the village scene were some of the many design decisions we made to highlight the importance of solar energy in the project as well as everyday life.”, explains designers at ODDS

The interiors of the restroom was inspired by the old-fashioned Indian bathrooms. It is installed with blue geometric tiles supplied by Heath Ceramics. With cheap mobility services, “More people in India have cell phones than toilets”. Keeping this in mind, a charging station with a bench has been provided which also seats visitors waiting to use the toilet.

In March 2014, the mobile container restroom was showcased at “Reinvent the Toilet Fair: India”, an event co-hosted by the Government of India’s Department of Biotechnology and the Bill & Melinda Gates Foundation.

Kohler hired local Indian artists to paint the exterior artworks, creating a lovely platform for their work to be showcased.


Mobile Restroom Concept


Side Views


Front and Rear View


Details of the Artwork


Local artists at work



Completed Mobile Restroom displayed with other mobile toilets


Mobile Restroom equipped with a solar-powered water-treatment system

+ Caltech


+ Kohler

+ Open Door Design Studio


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