MapRainwater harvesting is simply intercepting and storing rainwater for use in a variety of ways. In the UK many of us water our plants with rainwater. We save on our water bills and the plants benefit too, especially those which are lime-hating, as our piped supply in this area is taken from groundwater containing chalk.

A few are more adventurous in storing larger quantities of rainwater for flushing toilets and even, after filtering, for washing. There are environmental benefits too due to a reduction in chemicals used for treatment and power for pumping the water otherwise supplied by the utility company.
In Rwanda, where members of TRINITY have been visiting for the past 10 years, rainwater has been an even more valuable asset.

Once the cost of the infrastructure (gutters, pipes, tanks etc) has been provided, the system can be installed by local labour enabling the use of an essential, natural, free resource, sustainable for about 10 months of the year in much of the country. This includes Rusizi and Nyamasheke Districts in the far south west where I’ve been working on small systems for individual houses and large ones for schools and churches for the past 9 years.

Apart from the air we breathe, water is the most essential resource in life as we can’t survive without it for more than a few days. Whilst we can take it for granted here in the UK – just turning on a tap for a pure, reliable supply – that is not the case in Rwanda where many have to walk for miles to the nearest available source, in some cases a swamp, to fetch it in heavy jerry cans. Usually the carriers are women and children. The government have made good progress in developing water sources but there are still many who live in remote areas who do not have access, or cannot afford to pay and these supplies can still be polluted.

Dirty water 1

Rainwater harvesting, in combination with membrane filtration (another area of my work in Rwanda) is a huge blessing, providing safe drinking water, on the doorstep.

The benefits of household scale systems can be summarised as follows:

  • A relatively clean water supply at the point of use – often cleaner than alternative sources

Water tanks1

  • Improved personal hygiene resulting in less disease and consequently more time available for school or other tasks.
  • Less risk of assault on women in remote areas if fetching water from a source away from home.
  • Fewer injuries. eg carrying a full 20 litre jerry can weighing 45 lbs for several kilometres can damage a woman’s neck, hips and pelvic area (causing problems with pregnancy). The children also help carry smaller jerry cans and feel the strain (see below and right).


  • For any with a piped supply there are similar financial and environmental benefits to those listed above for those in the UK.
  • The associated benefits for the government are a healthier and more productive population requiring less healthcare and water supply resources.

The benefits of large systems are similar, especially for those schools with only a rainwater source.

I hope you will feel enthused to do your bit to conserve water and rush out and buy an extra water butt in the spring to store free rainwater for years to come! You will save on your water bill as well as the resources needed to treat your Southern Water supply – and your plants will prefer the natural product…


Rob Hoy