Puri­fy­ing water in an urban or sub­ur­ban envi­ron­ment after a nat­ur­al or man-made dis­as­ter

When dis­as­ter strikes, the first thing on most peo­ple’s minds is the well­be­ing of their loved ones and their own per­son­al safe­ty. Humans are pret­ty resource­ful crea­tures and can sur­vive with very lit­tle if forced to do so, but there are a few things that even the most capa­ble per­son can­not live with­out for very long. Next to oxy­gen, water tops that list. Humans can sur­vive only a few days with­out water, so in the event of a dis­as­ter, find­ing a clean water source is of para­mount impor­tance. Though dis­as­ter-pre­pared­ness experts like the Red Cross rec­om­mend that every­one has an ample sup­ply of water on hand, many find them­selves ill pre­pared when the need aris­es. For­tu­nate­ly, there are two rel­a­tive­ly easy ways to puri­fy drink­ing water, and gen­er­al­ly speak­ing, both meth­ods are avail­able to most peo­ple assum­ing you have the basics in your home.

Puri­fy­ing water by boil­ing

Boil­ing is the pre­ferred method of water purifi­ca­tion, as it kills bac­te­ria, virus­es and par­a­sites that can lead to ill­ness. If the water depart­ment sus­pects con­t­a­m­i­na­tion, a ‘boil water order’ will be issued, and tap water should not be used for drink­ing, food prepa­ra­tion or brush­ing teeth until it has been puri­fied; though, gen­er­al­ly, it is safe to use for bathing, laun­dry and oth­er house­hold needs. To puri­fy water by boil­ing, it should first be strained through a cof­fee fil­ter, a piece of cheese­cloth, sev­er­al lay­ers of paper tow­el or a clean piece of fab­ric to remove any dirt that is present. It should then be brought to a rolling boil and allowed to boil for one full minute. The one full minute is always under debate, how­ev­er, “most” bac­te­ria die at 165 degrees Fahren­heit.  Notice I said most. Only ster­il­ized, air-tight, food-grade con­tain­ers should be used to store the water, and milk con­tain­ers should be avoid­ed, as they do not seal well, not to men­tion they degrade over time.  I per­son­al­ly use col­lapsi­ble five gal­lon water con­tain­ers.

Puri­fy­ing water with chlo­rine bleach

The alter­na­tive method for water purifi­ca­tion is to use reg­u­lar house­hold chlo­rine bleach. Though this does kill most ill­ness-caus­ing bac­te­ria and virus­es, it most like­ly will not kill par­a­sites. How­ev­er, in the event of an emer­gency when there is no means of boil­ing and the option to pur­chase clean water is not avail­able, this method can be a life saver. After strain­ing the water via the method above, it should be poured into a ster­il­ized con­tain­er. A one-gal­lon con­tain­er is best, as the for­mu­la to treat this amount is quite straight for­ward. For one gal­lon of water, 1/8 tea­spoon or 16 drops of unscent­ed bleach is added. Then, this mix­ture should be allowed to sit for a full 30 min­utes. If any cloudi­ness remains after that time, the process can be repeat­ed. If the water is still cloudy at that point, it should be dis­card­ed. Excess amounts of chlo­rine bleach can be fatal, so this process should be repeat­ed only once before an alter­na­tive source of water is found.

Amount required and stor­age

Being ade­quate­ly pre­pared is always the best way to ensure that there is plen­ty of water in the event of a cri­sis. A con­ser­v­a­tive guide­line is to store at least one gal­lon per per­son per day and to keep at least a two-week sup­ply on hand. It is also impor­tant to take pets into con­sid­er­a­tion when cal­cu­lat­ing water needs, and extra water will be need­ed for per­son­al hygiene, dish­es, water­ing plants and oth­er house­hold needs. Both pur­chased and self-puri­fied water should be stored in a cool, dry place away from sun­light and used with­in six months but can be stored up to a year; base­ments are ide­al stor­age spots.