‘Rachel’s Water’ can prevent water shortages

Rachel Eustace, a second year student from Athy, has a novel idea for dealing with future water shortages in Ireland

First Published in March-April ed. of Science Spin

It seems odd that Ireland should ever experience water shortages, especially in recent years when rural Ireland has been repeatedly flooded by rainfall. That’s the way it is, that’s the way it always has been, but 14-year-old Rachel Eustace, a 2nd year at Ard Scoil na Tríonóid in Athy, has other ideas. She believes we should capture and use our rainfall.

In other countries people collect rainfall and use it for washing clothes, dishes and people. This rainwater is collected off roves and used for all purposes except drinking. In Ireland, we have good quality water available in rainfall, but we don’t bother catching it.

Rachael is clearly an articulate, very bright and practical girl. She wants to change the world, in her own way, but she has the talent to do it. It lifts the heart in Ireland’s darkest hour to see such enthusiasm, energy and talent in our young people. There is hope for us.

Rachel’s family gets most of its water from a well like their neighbours. During periods of heavy rain, and flooding, it is not possible to get water drawn from wells. This leads to the crazy situation where the fields all around can be flooded, while no-one has water.


Rachel thought to herself – and she is a practical girl remember – What can be done about it? She decided that she start to do something by taking samples of rainwater during rainy spells and send the samples off for testing to see whether rainwater was fit for drinking.

The people at Bord na Móna in Newbridge tested Rachel’s water samples, for water quality characteristics such as PH, conductivity, colour, turbidity and total hardness. The results came back. “They were all within standard – quite good results,” Rachel recalled.

These initial results were encouraging, but before Rachel could collect any more samples, the horrendous period of snow and ice before Christmas kicked in. There was no rainfall for sometime, as any precipitation simply fell as snow. Eventually, following the slow thaw, the first rains after the big freeze came and Rachel began collecting new samples.

These samples, which she numbered 3 and 4, were taken during the first rainfall events after the snow and ice. The samples were completely contaminated with bacteria, too many bacteria to even count. The reason for this was clear. During the freezing weather, the bacteria were not leaving the roofs of houses, they stayed there waiting to warm up.


Then when the weather finally did warm up, all the bacteria started to move, and they traveled down with the first rains of the warmer weather, down off the roof of Rachel’s home into her water collection container –a small, toy washing machine by the way. This mass migration of bacteria post-snow meant that there were massive concentrations of bacteria in these samples. This water was not drinkable, but the bacteria had at least left.

Two days later, the rain came again, and Rachel collected sample 5. This time the sample had no bacteria at all, she recalled. She was pleasantly surprised with the positive result. It showed that water quality collected from roofs can vary, but vary in a predictable fashion. The results show that it was important that  water is collected at least 15 minutes after rain starts to allow any bacteria present to make their way off the roof first. Also, to allow for a few days following a period of freezing conditions before samples are taken.

Based on all of this research Rachel came up with rainfall collection device. Her device had a screen to block out rocks and leaves. She used filter paper to stop muck and dirt getting into the water, and a micropore filter too, to stop smaller particles and bacteria. The water was then put in sterile bottle and exposed to ultra violet light. This light, many scientists now believe, can kill off 99 per cent of bacteria and viruses that may be present.

She had learned this from researching her topic, and applying it to improve her device.

Rachel was surprised by the positive reaction at the BT Show from members of the public to her water collection device. Some said it would be a great thing, once water charges came in, and water became expensive, while others asked her  when it will be available for sale. The interest got her thinking. She had not been planning to try and develop a saleable product, but now she feels she might like to do that. Her teacher, Ms Ní Fhaoláin agrees. No doubt we’ll be hearing more of ‘Rachel’s water’ in the future.