Hesperian Health Guides
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Collecting rainwater is one of the easiest and most effective ways to have a safe supply of water. Rainwater is safe to drink except in areas with a lot of air pollution. Rainwater collection is a good solution to both water scarcity and water safety.
Above ground tanks can be placed next to the house. The roof will catch rainwater and divert it into the tank. Roofs made of tin or corrugated metal are best. Roofs made of thatch may collect too much dirt to be safe. Roofs made of lead, asbestos, or tar have toxic chemicals in them that will make the water unsafe to drink. Make sure your rain barrel is clean and was never used to store toxic chemicals, such as oil or pesticides.
|Using a tin roof to collect rainwater|
Ground catchments can collect surface runoff and rainwater. To make a simple catchment, dig a depression into the ground and press down the earth or line it with clay, tile, concrete, or plastic sheeting. These reservoirs can be used to give water to animals or to collect water for bathing. If a ground catchment is used for drinking water, it should be fenced to keep animals out. Water from ground catchments should be cleaned before drinking.
Water collected on roofs or in ground level catchments can also be diverted into underground tanks for storage. This is a good way to keep water cool and covered. It may also be less costly than building or buying above ground tanks.
Make rainwater safe to drink
Rainwater must be kept free of contamination to be safe to drink. To make sure the water you collect will be safe:
- Clean the tank, entrance pipe, roof, and roof gutters before the rainy season.
- Never collect water in containers that have been used for oil, pesticides, or other toxic chemicals.
- Allow the first rains of each year to run through the tank to clean it.
- Cover the tank and place a filter or screen over the inlets to keep out insects, leaves, and dirt. This will also help prevent mosquitoes from breeding.
- Take out water through taps, if possible. If water is removed with buckets or other containers, make sure they are clean.
- For added safety, add chlorine to the tank or connect a water filter to the tank.
- Do not stir or move the water. That way, any dirt or germs in the tank will settle and stay at the bottom.
- Sweeping the roof from time to time will also help keep collected rainwater clean.
Collecting rainwater in the desert
One way rainwater is collected in the Thar Desert of Rajasthan, India, is in village ponds, called naadi. Everyone in the village, and even people passing by, may use naadi water.
Everyone in the village works together to maintain the naadi. Ancient laws prohibit any trees from being cut near the edges of the naadi, or in the area where rainwater collects and runs into the naadi. Animals are kept away from the naadi, and people are not allowed to urinate or defecate near the naadi. Once a month, on the day of no moon, the entire village works to dig out any sand and silt that has collected in the naadi. Digging out the naadi makes it deeper and also removes germs that may have settled on the bottom. After digging it out, the villagers allow the water to settle so it becomes clear again. In these ways the community comes together to protect their water.