Sustainable OneWorld Technologies C.I.C.

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In many parts of the world there are two main seasons, the dry season and the wet or rainy season. Typically in the wet season, the rain comes in sudden heavy bursts that last about an hour. This season may only last for two or three months and the rest of the year there is virtually no rain. In the past the timing of these rains have been predictable but climate change is making the rains more erratic and more extreme giving rise to floods and droughts.

Current practice today

When the rains come there is little or no ways of collecting and storing the rain for use when it is needed

Ambitions for a better solution

SOWTech have sought to design and develop system that can collect the rain falls on roofs and store it until it is needed:

The "SOWTech Design"

Western style gutters can not be easily fixed to overhanging corrugated tin roofs. The open gutters are also prone to overflow if the rain is too heavy either by “bouncing out” or because the rain cannot flow away quick enough. SOWTech have designed flexible guttering that can wrap around to contain the water and be transported away in large bore pipes. These large bore pipes lead into buffer tanks so cheaper smaller bore pipe can take the water from the buffer tank to the storage tank.


Using roof areas and rainfall figures, large tanks that can accommodate a whole seasons rainfall are provided. These tanks are assembled in situ using local labour. The tanks are enclosed to minimise the insects and debris entering the water. The water in the tank is then available for use in the dry season for watering crops, washing and, if treated, can be used for drinking. The water in the tanks may not last for the whole of the dry season but it will provide water for use when it is most needed.


A pilot scheme has been installed in a school in Zimbabwe sponsored by Africa Trust.

Interseasonal rainwater harvesting

What we do

Rainwater harvesting