You can drink rainwater but after it lands on a surface such as your roof and then goes into a rain barrel etc then you need to boil it or purify it to make it safe for drinking.
Although if you just sit a cup or bucket out in the rain that is clean then you can drink the rain water without boiling it or purifying it.
You cannot drink ocean water or sea water as it's way too salty and drinking ocean water or sea water can be deadly to humans who drink it.
If humans drink seawater, our cells are thus taking in water and salt.
While humans can safely ingest small amounts of salt, the salt content in seawater is much higher than what can be processed by the human body.
The reason humans can't drink river water is because of the potential of bacteria and parasites that could be in the river water.
However humans can actually drink river water if the river water has been purified or boiled before drinking it.
Water should be boiled for at least 1 minute to kill parasites and bacteria and to purify it.
You can make the water microbiologically safe to drink by bringing it to a rolling boil for one (1) minute.
Boiled water is not the same as distilled water.
Boiling water just kills bacteria and parasites while distilled water is water that has been stripped of all impurities, including minerals and microorganisms.
The difference between distilled water and purified water is the purified water is water which has had the chemicals and contaminants removed, but it may still contain minerals.
Distilled water on the other hand is water that is also purified but is also water that has had both contaminants and minerals removed.
Rainwater is actually distilled water as the rain water is evaporated by the sun naturally and goes through a natural vapor and water process that distills the water naturally.
When rainwater goes into the ground then it becomes mineral water.
You cannot make distilled water in a microwave but you can on the stove.
In order create distilled water through vaporization, as would happen in a microwave, you would need a way to collect only the vapor water.
Bottled water is not distilled as it simply goes through a filtering process and then it's bottled.
Bottled water is basically tap water coming from a city supply line that is purified.
Distilled water on the other hand goes through a heating process that distills it and it's sold as non drinking water.
The process of distilling water is simple: Heat tap water to the point that it turns to vapor.
Then the vapor condenses back to water, it leaves behind any mineral residue.
The resulting condensed liquid is the distilled water.
The reason you shouldn't boil water twice is because you risk concentrating certain undesirable chemicals that may be in your water which include nitrates, arsenic, and fluoride.
To naturally purify water you can use a water purifying filter or pitcher.
You can also purify the water naturally by boiling the water and allowing it to cool before drinking it or cooking with it.
Boiling water does purify the water and also help to kill parasites and bacteria.
You can drink pond water if you boil it.
Boiling the pond water is a good way to kill any potential parasites and bacteria that could be in the pond water.
Not all pond water is actually unsafe to drink without boiling but you should always boil any water from a pond or other unknown source just to be safe.
I actually drank some water out of a creek that was flowing but the water was flowing and not sitting stagnant like in a pond.
That was 10 years ago and I never got sick from it.
But with pond water I certainly would boil the pond water to be safe.
Boil water, if you do not have bottled water.
Boiling water is sufficient to kill pathogenic bacteria, viruses and protozoa.
If the water is cloudy, let it settle and filter it through a clean cloth, paper boiling water towel, or coffee filter.
Bring water to a rolling boil for at least one minute.
Straining the water through a coffee filter or other cloth will remove the larger particles.
At a minimum, boil the water for a couple of minutes.
Adding 8 drops of regular chlorine bleach per gallon will accomplish the same level of treatment in 30 minutes.
Even if your pond or lake has low bacteria counts, there is still a risk that you could come in contact with something that could make you ill.”
Swimming or playing in unsafe water may result in minor illness such as sore throats or diarrhea.
Does Boiling Water Remove Chlorine?
Yes, boiling water for 15 minutes is one way to release all the chlorine from tap water.
At room temperature, chlorine gas weighs less than air and will naturally evaporate off without boiling.
Heating up water to a boil will speed up the chlorine removal process.