In the event of an emergency getting clean water is the most important thing you can do (other than shelter from the elements).  After a natural disaster water lines maybe broken and local water sources would be contaminated.  Boiling the water will destroy any microorganisms in the water, but you will still have bad flavors and murky bits in the water.  It is easy to make a water filter out of easily accessible items.

Needed items

• empty 2 liter soda bottle
• clean piece of cloth
• knife or other cutting tool
• sand
• gravel
• charcoal from a fire or aquarium filter

First cut the bottom off of the soda bottle.  Only cut off the very bottom of the bottle, you want to use most of it as a funnel for the water.  Put the cap back on the bottle and put a small pinhole into the cap for the water to drain out of.  Wad up your cloth and put it into the bottom of the bottle.  Next put the charcoal into your filter.  This will filter out the flavors and smells from the contaminated water.  Also it will remove some of the toxic metals from the water if there are any present. Then add a layer of sand than a layer of gravel.  You have now completed your basic emergency filter.  You can get about 10 gallons of water filtered with it depending on how bad the water coming in is.  A simple cloth filter used on the water before you use your purifying filter will prolong the lifespan of it.  This filter will not filter out microorganisms, and the water will still need to be boiled to kill them off.  Just because water is clear doesn’t mean it is safe to drink!  Always be careful!

A good variation that you can store of this filter is to use a 2 inch PVC pipe in place of the 2 liter bottle.  Seal a pipe end cap on one end and make it as you would the 2 liter.  When you finish you can seal the top with food grade wax to keep the layers from shifting or getting contaminated.  When you need it drill a small hole in the capped end and pull the wax off the other end.  And you have a ready-made filter for an emergency.