I would not expect fresh rainwater to have any biological impurities, but what about chemical impurities? Have decades worth of antipollution measures made that a moot point?
Thanks,
Rob
There are a lot of variables including how it was collected. Has it landed on a roof and flowed through a gutter to a collection point? Weather conditions can have an impact as well. I am by no means an expert, but I’ve worked on water sanitation projects in the developing world and it is usually recomended that rain water be used for irrigation and washing, not drinking. If you are going to drink it, you should boil it first.
Google “acid rain.”
Acid rain is pretty unusual these days (unless you live in or near China), and in any case it’s pretty harmless to drink in small quantities. The worst acid rain has a pH of about 2.5 – which is about the same as a Coke.
It might not taste very good, though.
In the small Texas town where I grew up, nearly everyone had a “rain barrel” under the downspout of their gutter system. Women used rain water for their house plants and for washing their hair. Other than that, I don’t remember any specific use; when the barrel was full, it was tipped over and emptied. I don’t recall anyone ever using it as drinking water.
I find this “rainwater is a life threat” notion a bit unlikely.
I can’t see what bio-hazard there is going to be in freshly collected rainwater that necessitates boiling (presuming the container itself is not the source of contamination). The water gets into the atmosphere via evapouration, which is effectively boiling. What algae, protozoa, bacteria is going to contaminate the water up in the clouds?
Coming from the Australian bush, usually you had the option of the rainwater collected of the homestead and maybe one of bore, channel or river water.
Rain water collected of a galvanised iron roof, collected in a concrete tank, or a concrete lined corrogated iron tank, or more recently a plastic tank. Good water, and never needed to be boiled. You drank rainwater and possibly washed clothes in it, using the other (usually muddy or high in minerals) for the garden, toilet and other general puposes.
We’d use rainwater collected in glazed earthenware as distilled water to top up car/tractor batteries.
Lots. The atmosphere is full of organisms, including bacteria, pollen, algae, fungi, insects, and viruses. There’s an entire branch of biology devoted to its study. Some of the atmospheric biota is involved in the transmission of human disease, including through airborne water.
I think it’s also the “freshly-collected” bit that causes problems.
As soon as the water sits in one place for a length of time it’ll start to go stangnant, and could grow all sorts of algae etc.
Yes, and we breathe that “cocktail” all the time generally without ill effect, not withstanding instances of hypersensitivity, hayfever and asthmatics etc.
I’m disputing the need to boil rainwater, presuming the container doesn’t introduce contamination. It’s not some developing world issue. I reckon there’d be a large slab of the North American farm sector who live on it, without the need to routinely boil it. That applies on this side of the puddle. Appropriately stored, It would be better quality than any supply sourced from surface water, be that river or lake.
And if water sits in a puddle on the ground, or a container long enough to become stagnant, that’s not rainwater, and the nutrients and algae more likely to have been introduced since it fell.
At home our main water supply was a 250kl (66,000 US gallons) tank. Keep the leaves, dust and wildlife out of it and it supplied potable water for over 40 years. Nothing unusual from our perspective.
Depends on where it’s falling, IMO. I wouldn’t use urban rainwater directly for drinking as it’s probably got a fair amount of pollution in it, from falling through all the dust and combustion products and “NOx, SOx and VOCs” that are in the air from automobile exhaust, industrial emissions, wood/coal smoke, evaporation of volatile substances, and other sources. Antipollution measures have helped reduce, but have not eliminated such things, particularly in urban areas. One thing there is definitely much less of in the atmosphere now is lead, due to the replacement of leaded gasoline with unleaded, but once upon a time not that long ago, it would be a real concern for drinking and even gardening with urban rainwater. That said, water collected from the sky is still a lot cleaner than that which is running off of ground-level surfaces such as roads and pavements, or sitting in/on the ground having various pollutants dumped into it.
It also depends on how you’re collecting it, what type of surface it’s running off of, and what might have been deposited on said surface since the last rain. Many rainwater collection systems include a “first water” or “foul flush” disposal stage that either filters, rejects or withholds the first bucketful or so to avoid collecting the chemical-laden dust, bird waste, insects, and other pollution that has been deposited on whatever surface it’s running off of (roof, etc). This water can be diverted to use as lawn irrigation or other purposes where the water doesn’t have to be so clean as for washing and drinking.
Then too, there can be a brick or bag of some mineral substance (limestone, shell, marble chips, etc) to make the water alkaline in the the reservoir, that helps to prevent certain kinds of chemical impurities (acids, salts, heavy metals, etc) by adsorption or neutralisation or precipitation or whatnot. Rainwater is slightly acid to begin with from the carbon dioxide, nitrogen, etc in the air and my Permaculture Design Manual says that “washing and shower water can be soft (acid) but the water we drink is best made alkaline for the sake of health.”
Indeed, washing water works best if it is soft, which is why rainwater has been used for so long for washing clothing and hair – it helps to rinse out the alkaline soap residue, which was what made clothes dingy and hair heavy and flat before the advent of commercial detergents and shampoos. So it’s probably best to have separate rainwater storage tanks for washing and drinking water, so that each has the best properties for the purpose. The collection surface can be the same, just leave the alkalinizing material out of the wash-water tank.
A couple of good diagrams included here:
Wateraid International Sustainable Technologies
A good look at rainwater collection:
Permaculture water harvesting write-up
Another page with extensive information, photos, diagrams, and references:
My Permaculture Design Manual also has a couple of good diagrams that show some collection and storage systems that can be built at home, but I haven’t been able to find them online yet.
pH doesn’t tell the whole story, though, and almost all acids that strong will cause chemical burns. Coke specifically won’t, but it’s the exception, not the rule, and I certainly wouldn’t want to drink a pH 2.5 aqueous solution of sulfuric acid (which is pretty much what acid rain is). That said, though, acid rain is, as you say, awfully rare in the western world nowadays.
You can drink rain water safely. Collect it without contaminating it. Have you heard of a kid dying from eating snow or the people that melt it for drinking and cooking?
My grandparent had a wooden cistern to collect water. They drank it for over thirty years. It stood beside the house. Their well water had too much iron to use for anything except laundry and showers.
Today, people use plastic cisterns.
On further reflection, when I first lived in Florida back in the 1960s there were still many houses with above ground cisterns; the easily accessible ground water smelled and tasted like rotten eggs. Those above ground cisterns relied entirely on rainwater and that water was used for everything in daily life, including cooking and eating. Way back then, water from springs, creeks and rivers could be used for cooking and drinking (drinking it was chancy) but that sure as hell ain’t safe now.
Helps keep away Commies.
Malaysia’s largest mosque, the Blue Mosque in Shah Alam, has a gargantuan dome made of aluminum covered with vitreous tile. It was built with channels to collect rainwater into storage tanks. The rainwater collected off the dome is used not for drinking, but for ablutions (which includes gargling, however). It’s actually very ecological, since Muslims use vast amounts of water, and this would reduce the demand on the city’s water supply considerably.
Plenty of other animal life survive off rain-water, correct? Surely (becky?) were not the exception.
I just wanted to re-emphasize Jeneva’s point about flushing the “first water”. Rainwater itself may be clean where you live, but if your locale has wet and dry seasons like most places, it can be several weeks or even months between rains. During that time, a lot of stuff can collect on your roof (or whatever collector surface you use) – air pollution, animal and plant matter, bacteria, chemicals leeching out from the roof itself, etc. You don’t want to drink that.
Whether the rainwater is drinkable depends on factors that vary from place to place and maybe even from month to month. And really, this is the same reason you use water filters when you go camping: 90% of the time you’ll be fine without it, but 5% of the time you might get a bad stomachache and then 0.1% of the time you may end up somewhat dead. Is it worth it to you? Only you can answer that. If you want to be safe(r), boil the water, get it tested on a regular basis, install a filtration system, or do all the above. Appropedia also lists a few lower-cost or lower-tech water filtration methods that you can use in conjunction with the rainwater catchment, or if your area is hot enough, there’s also solar distillation.
@ Jeneva: It’s neat that you’ve heard of Appropedia (or did it just come up on Google?). I work with one of the guys who started it… neat to see it getting mentioned here 
Maybe this is a whoosh, but plenty of animal life survives off things that would kill us. Clean North American rainwater probably wouldn’t kill us, but contaminated water in general can certainly cause anything between mild discomfort to mass deaths in less-developed nations.
How do Muslims use more water than any other religion?
They have to pray five times a day, and before they can pray they have to splash water on their faces, arms, feet. After sex they have to have a whole body bath before praying. Any time going to the bathroom involves cleanup with water too. Islam is just a watery lifestyle.
Judaism (and, to a lesser extent, Christianity) are also rife with superstitious ablutions. As with Islam, however, the degree of compliance varies from sect to sect and individual to individual.