Low-cost Rainwater Storage System

The Challenge

EnterpriseWorks/VITA sponsored this Challenge, soliciting design ideas for a low-cost rain water storage system that could be installed in households in developing countries. The purpose of the Challenge was to facilitate access to clean water at a household level, addressing a problem that affects millions of people worldwide who are living in impoverished communities or rural areas where access to clean water is limited. Domestic rain water harvesting is a proven technology that can be a valuable option for accessing and storing water year round. However, the high cost of available rain water storage systems makes them well beyond the reach of low-income families to install in their homes.

A solution to this problem would not only provide convenient and affordable access to scarce water resources, but would also allow families, particularly the women and children that are usually tasked with water collection, to spend less time walking distances to collect water and more time on activities that can bring in income and improve the quality of life.

Photo of people carrying water

The Realization

Joern Lutat lives in Germany with his wife and two children. He is a college lecturer in mechanical engineering and owner of an engineering company that specializes in the design of tourist submarines.

Joern has been featured in Wired for an award-winning collaboration with students to develop a prototype for a NASA space elevator contest. He continues development of a low-cost space elevator, currently as an open-source engineering project that employs a novel mechanical catapult design. His past projects include development of a Mars robot, bikes for handicapped people, an energy-saving wood stove for developing countries, an underwater habitat for LEGOland Germany, and portable osmotic water purification systems.

Photo of Solver, Joern Lutat

Joern’s solution involves a foil inlay within a bag made out of tough woven polypropylene fabric. The bag employed in his solution was already mass produced for packaging dry and semi-moist materials, but it had not been applied to water storage before. The outer bag provides the strength to contain a ton of water while the lightweight foil inlay provides liquid impermeability. The product is lightweight, easily transportable, and can be folded into a small retail package.

The water reservoir was only part of Joern’s solution — he also proposed designs for rainwater capture from the roof by fitting a foil tube to a gutter, a nylon water filter, and an outlet and valve system to easily drain water from the reservoir.

Photo of Joern

The Solution

Dr. Farshad Rastegar, CEO of Relief International, parent agency of EnterpriseWorks/VITA says he believes the innovation is a “game changer” in the world of rainwater harvesting. “Within the next decade the storage bag will make a major dent in the problem of water faces by tens of millions of families around the world. It does so because it is simple, affordable and scalable.” The solution is built around an existing product that is already being manufactured, making testing and modification process less complicated.

Over the past two years since the contest ended EW has taken the product forward. Modifications have been based on field testing in 150 households in Uganda, focus group discussions with potential clients and inputs from manufacturers. The rainwater bag has come a long way from the initial idea with a new shape to make it more stable as well as features required by the consumers, including a brown color, outlet tap, and inlet screen. It actually holds almost three times as much water as was required — more than 350 gallons.

The greater the capacity of the device, the less the demand on the women who now must carry water to their villages from distant water sources — the average roundtrip worldwide is 3.7 miles. As a result, women will be able to spend more time working in the fields or taking care of children, a major economic benefit for the family. Teenage girls who now help with the daily water carrying will now be able to attend school.

In March of 2011 “bob” the rainwater bag was formally launched in three districts in Uganda with a promotional campaign using radio, print and live events promoting “bob” with sales through existing commercial channels. The ease of transport, low cost and large storage volume are the key selling points.

Tabitha Tusingwire, an Ugandan woman used collect water from a nearby borehole. When the borehole was down, she had no choice but to walk 30 minutes to an unprotected water hole — three to four times a day. “I no longer suffer walking long distances four times a day to get water from the well whose water is very dirty,” Tabitha said, adding that she is relieved to no longer have to struggle to provide water for her family.

Bob only costs $54 USD, and allows women like Tabitha to spend more time working outside the home, in roles that enable them to earn money. Those who have benefited from bob have found not only relief from long trips to water holes, but also improved health and more time to use on other work – both in and outside the home.

bob at Relief International
rainwater bag was formally launched