And vultures can eat rotten meat. But, personally, I’ll pass.
I love the idea of solar stills. I would include a large sheet of transparent plastic in any survival kit I made up, mainly for that purpose. You can collect clean water just by digging a pit, putting fresh non-poisonous greenery in it and covering it with clear plastic, with a small rock or something in the middle to form a point for the condensation to run off into a container. Include a long tube that can sit in the container and emerge from under the plastic, and you don’t even need to dismantle it to drink the water. 
I had actually never heard of it until I was Googling for good examples. It seems like a great project, I’ll definitely give it a closer look. I’m always keen to find good resources for this sort of thing, bit of a passion of mine really.
Yes, it seems that a lot of other animals, especially those which are commonly carrion-eaters, can tolerate a broader range and higher volume of biological contaminants than we can. Whether they’re any less susceptible than us to chemical contamination, well, I wouldn’t bet the farm on that one. Some, like amphibians, are noticeably more sensitive than us to certain chemicals. And we don’t really have any records on the number of wild animals regularly killed or sickened by contaminated water, do we?
The most acidic rain measured in the U.S. has a pH of about 4.3, with more typical values for acid rain ranging between 4.5 and 5.0. This acidity comes from sulfuric acid and nitric acid that result from sulfur dioxide and nitrogen oxides present in the emissions from power plants, vehicles, and factories.
Note that while pure water has a pH of 7.0, even clean, uncontaminated rainwater has a pH of approximately 5.6. This is because of the presence of CO[sub]2[/sub] in the atmosphere (which dissolves in rain to produce a weak solution of carbonic acid).
Note that a solution with a pH of 2.5 is 100 times more acidic than a solution with a pH of 4.5. While classic Coca Cola does have a pH of about 2.5, it is much more acidic than typical acid rain. Typical acid rain has an acidity somewhere between orange juice and black coffee.
That being said, acid rain does cause enormous damage to ecosystems. It’s not that unusual, either, but the Clean Air Act and other environmental regulations has helped in this respect, and it’s certainly not as bad as used to be.
To address the OP, rainwater is perfectly safe to drink. I might prefer not to drink rainwater immediately downwind of an industrial smokestack, though, out of an abundance of caution, but even then it would likely not be harmful.
We catch it off the roof here in the West Indies and drink it after storing it in plastic tanks or underground cisterns. People usually have a filter on their cistern water and obviously cisterns need to be drained and cleaned from time to time as do the tanks.
We had no water over the weekend (burst pipes) and collected freshly-fallen snow to melt for flushing the toilets. The snow was pristine-looking: artic white, fluffy, gorgeous.
The water that melted from it once we microwaved it? Yuck. It was reddish. Definitely not for drinking without further purification. (Fine to poop and pee in, though.) I’m in an urban area - YMMV if you’re away from civilization and attendant pollution.
I should clarify that precipitation collected directly in a clean container is safe.
Rainwater running over the ground or a roof first may not be safe to drink. Snow may not be, either, depending on how long it’s been on the ground.
Is this really a significant amount of water? Splashing aside, don’t most people use water after going to the bathroom and take baths after sex?
“Islam is just a watery lifestyle” – that’s just hilarious 
Technically, you could do the entire ablution with just half a pint of water. You’re actually supposed to use water sparingly like that. But the average modern Muslim is likely to leave the tap running the whole while and easily blow a gallon per person each time.
Good thing this question has nothing to do with rotten meat, I wouldn’t know how to answer… Food is food and water is water which btw, we need to live. I’m sure if it came down to it my survival instincts would look around for a needle and pop my air tight bubble and then it would knock me to the ground and drag me to the closest puddle and force me to drink it while I’m “trying” to scream for help. I should be thankful though because I just lived a little longer thanks to that dreadful rainwater. But there is always a catch, live now die later. Wait a minute, that’s the catch for everything I do. You almost had me convinced vulture watcher, I was about to quit hunting with Dick Chaney.
Quoth Jeneva:
This is something that I’ve brought up before, too: If there’s something that kills, say, 5% of the population of some wild animal, the population is probably going to be able to keep up with it, and it won’t really have a big effect on the numbers in the long run. But if something kills 5% of the humans that are involved with it, we’d consider that a huge tragedy, and be militant about taking steps against it. By the standards of survival of the species, it’s still not all that big a deal, but we tend not to think of human lives in just those terms.
Rainwater is awesome. I prefer it to tap. I don’t have to haul it and it possably has less chemicals in it than tap.
I gotta ask… have you been drinking much rainwater lately? 
Well, quite.
I need to jump in on this one. Take a look at a map of New York State that shows the counties. Then look east of Lake Ontario. You’ll see an area where Oswego and Lewis Counties have a common border. Make a sinuously-straight line hugging the northern half of that border in a roughly north-south alignment along the east, Lewis County side. That is a stream called Prince Brook, part of the Salmon River watershed. This is in the area of the U.S. which gets the highest snowfall east of the Rockies.
The reason I single out Prince Brook is that it is fed largely by snowmelt, being a rather unimpressive trickle during late summer and fall, though with heavy flows in the spring. And during the height of the concern over acid rain, before air pollution retrofits were demanded on Midwestern factories, power plants, etc., Prince Brook had a spring-runoff pH of 1. That’s equivalent to table vinegar. Granted, this is an extreme – that’s why I picked up on it, because it was an extreme, to illustrate how bad acid precipitation could get.
A pH of 1 is far stronger than table vinegar. In fact, Coke is significantly stronger than vinegar. The only things you’ll find in your kitchen with a lower pH than Coke are cleaning supplies.
Polycarp, can you find a cite for the pH of 1? I’d believe that if it was due to some kind of mining leftovers, but for snowmelt, I’m just not seeing it.
what if you live in Japan?
A pre-school somewhere in Auckland a couple of years ago wanted to install rain-water collection tanks for the school’s use, but where forbidden to do so, IIRC. I heard this at a local community board meeting, when experts were reporting about zinc contamination in our local streams – from unpainted and unsealed galvanised iron roofs. Aside from bird droppings and the like, zinc (if using a galvanised iron roof as the collection source) might be the only other major concern about rainwater.
Out in rural areas here and the off-shore islands, rainwater is a necessity where there’s no reticulation. Haven’t heard of any community dying in droves due to using it.
In Hatti rainwater is usually collected off gutter systems to use as household potable water including drinking.
In wilderness situations rain water is usually considered safer then some water sources such as lakes. IMHO taste wise rain water is a bit lacking over ground water or a flowing stream source.
I own some land in Tasmania in Australia. So far I have no road, power, water or house, it’s just land. But all my neighbours have water tanks that collect the rain water from the roof. An 80,000 litre tank is enough to last through the summer for all water, showers and everything and it’s not that big.
So the answer is yes 