From rainwater to drinking water: how to do it

You can’t imagine it now, but if no more water comes out of your tap, you still need to be able to drink. Making drinking water from rainwater is a good option. Collecting and purifying it provides you with a backup for emergency situations and can also contribute to a more sustainable lifestyle.

Water independence

In the event of power cuts, pipe bursts or extreme weather conditions, you may temporarily be unable to drink your tap water. I previously discussed six ways to make drinking water yourself. We also went into further detail on how to safely drink water from a river.

Quality of rainwater

Do the same requirements apply to rainwater? Naturally, fresh rainwater is free from chemical additives such as chlorine, fluoride or other treatment agents that we find in tap water. However, it can pick up contaminants during its fall through the atmosphere and through contact with collection surfaces. It’s always useful to test your collected water with a test kit.

Collecting and filtering water

Roof surface

Usually your roof will be the largest available collection surface. Metal roofs such as zinc and aluminium provide the best water quality, whilst asphalt roofs can lead to contamination.

The first dirty litres

The first water that falls on your roof washes away dust, leaves and bird droppings. To ensure that these first dirty litres don’t end up in your storage tank, you can use a first-flush diverter.

Such a first-flush diverter collects contaminated first litres and diverts them away from your water tank. Without complex chemical installations, this can significantly improve your water quality.

Practical tip: Install gutters with fine mesh grilles to prevent coarse contamination before the water reaches your collection system.

Below we have selected several products that you can use to store rainwater cleanly.

Purification methods for drinking water

Afterwards, it’s time to get to work with your collected rainwater. Currently you can already use it to flush your toilet or water your plants, but to drink the water safely it still needs treatment.

Sedimentation and settling

First let collected rainwater stand for 24 to 48 hours. The heavier particles sink to the bottom, after which you can draw off the clear water with a slightly higher tap. This natural form of purification is the first step.

Filtering

Afterwards you need to filter your rainwater. This can be done in various ways: with mechanical filtration, using carbon filters, UV filters or by adding water purification tablets.

Warning: When you filter water, it also loses a number of essential nutrients such as minerals. If you switch to filtered rainwater for a long period, you must obtain these substances from other food sources.

Storing drinking rainwater

A hygienic storage tank

Choose storage tanks that are intended for food use and that don’t release substances into the water. Dark tanks can prevent algae growth, but it’s recommended to check regularly for contamination and clean them thoroughly at least twice a year.

Maintaining quality

Adding a few drops of chlorine bleach ensures that your water stays good for longer. This prevents bacterial growth without strongly affecting the taste. Test your water regularly for bacteria and chemical contamination as well. This way you can be sure that you’re still drinking safe water!