How to Filter and Purify Rain Water for Home Use

If you’re interested in becoming self-sufficient, one of the first steps you’ll have to make is to make sure you have enough drinkable, clean water for everyday use.

Even if you own a well or rely on a municipal water supply, you should still make sure that you have an alternative source. One such source is rain water. After you filter and purify it, it’ll be fine to drink and to use in any other way – cleaning, dish-washing, bathing, watering plants etc. What’s more – municipal water supplies very often contain chemicals you certainly don’t want, thus it should be filtered before consumption as well.

The purity of water determines your health. It’s actually the only fluid your body needs – when you drink it, make sure the water is filtered and purified before consumption or even before using it as bath water.

Here’s how:


Ideally, you’ll want all the rain falling on the roof of your secluded house to go into such container through the gutters. This however will only generate approximately 800-3500 liters of clean drinkable water a month, depending on your location, the season and the size of your roof. That’s not enough to sustain a family or group bigger than 3 people. And you must remember that in most areas approximately 2/3 of rainfall will occur during the summer season. It’s still a great way to have some backup clean water that’s good to drink, and if you don’t use too much of it too e.g. clean stuff around the house, you could possibly get by on just that for a significant amount of time. Naturally you’ll have to maintain your roof so it’s clean of bird droppings, leavings from other animals that have access to the roof and other contaminants. If you can’t do that, use a separate container to collect the water.

I recommend adding another layer of charcoal or activated charcoal in the outlet pipe – separated with a cheesecloth from both sides. It’s by far the best natural filter of chemicals readily available to you.

The trick is to keep the layer between the diffuser plate and sand well oxygenated and to make sure the water slowly seeps in – as opposed to just pouring through the layers. This will create a bio-film of organisms called Schmutzdecke similar to those living on the bottom of a pond or some other still body of water – they prey on all sorts of harmful little bugs, viruses, sporidia, giardia and others and so will gladly help to filter your water – the natural way. It’s crucial that the input water doesn’t disturb the Schmutzdecke. The filter requires at least several days up to a few weeks of operation for the Schmutzdecke to fully develop and be effective – allow for that time and always test water before first use. The water from that period should be diverted back into the environment.

Remember to prepare enough sterile containers to hold all the water you’ll be collecting, filtering and purifying. Alternatively you could install a single bigger vessel to hold all the water you need – this way you can heat it when necessary and basically have the same convenience of using tap water without having to rely on anyone but yourself. Your complete system will then look something like this:


Additionally, you can use standing water  – which cannot be consumed, since it contains many very harmful critters – or river or spring water, lake water, or shallow well water and filter it to make good water fit for consumption. Altogether it may very well add up to your total water self-sufficiency – something worth striving for since municipal water is of worse quality every year, containing harmful chemicals like chlorine, aluminum and others. Aluminum alone has been proven to cause cancer, Alzheimer and to negatively affect children’s nervous system.

The only maintenance you’ll ever have to perform is to replace the activated charcoal occasionally and to stir the Schmutzdecke if it becomes too thick and makes the water filtration and purification process too slow. It may sound a little tedious at first, but it really isn’t, and once you’ll get your water treatment system up and running, it’ll take very little to no effort for you to maintain total water self-sufficiency.

Related post: How to Filter and Purify Water in the Wild.


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