Can water go bad?

Many people store water for emergencies -- but is it true that water sitting for too long will go bad? Listen in as Marshall Brain breaks down the science of water purification in this HowStuffWorks podcast.

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Episode Transcript

Speaker 1 (00:00):
Welcome to brain Stuff from HowStuffWorks dot com where smart Happens. Hi.
I'm Marshall Brain with today's question, can water go bad?
Many people store water for emergencies like hurricanes and power failures.
This is especially true in rural areas where drinking water
comes from private wells. These wells are useless unless there's

(00:22):
power to run the pump. It turns out that there
are two ways for water to go bad. You can
easily demonstrate the first way by filling a bucket with
tapwater and leaving it out on the back porch for
several days. After about a week, you'll find that the
water in the bucket contains mosquito larvae, algae, and various
other life forms, none of which you would want to

(00:43):
be drinking. From this experiment, you can decide that storing
water in an open container is a bad idea unless
you have a plan to purify the water when you
need to drink it. Storing water to close container works
no better if that water that you place in the
container is contained eminated in some way. You need to
put pure water in a clean container and then process

(01:05):
it in some way to eliminate bacterial contamination. You can
process the water with heat, just like you do with canning,
or you can use a chemical like chlorine or iodine.
The second wave for water to become unfit for drinking
is for something from the container to leach out into
the water. As an extreme example, imagine what would happen

(01:25):
if you were to store water in a lead container.
Lead would leach out into the water and make it poisonous.
The container you use needs to be made from a
food grade material in order to avoid leaching problems. Glass,
stainless steel, and some plastics are food gray. Do you
have any ideas or suggestions for this podcast? If so,

(01:46):
please send me an email at podcast at HowStuffWorks dot com.
For more on this and thousands of other topics, go
to HowStuffWorks dot com.