Post Event Considerations

Basic needs


Water availability requires four basic elements: a source, treatment, stoage, and distribution. At a minimum, one should expect to need about a half a gallon a day per person if there is no use of water for non-drinking purposes. The numbers increase as the usages increase. There are a number of options for supplying potable (safe to drink) water in emergency situations. UIf access to neighboring water utilities it not an option, the remaining options could include bottled water supplied or local produced water. Locally produced water might include packaging of pre-treated water, mobile treatment units for the existing water system, or individualized local treatment.

At the system level, this could include disinfection, a membrane system, or filtration. If treatment is to occur at the point of use, this could include disinfection, filtration, or boiling. Boiling water is the most accessible method. To make water safe to drink via boiling, one must bring the water to a full rolling boil (lots of bubbles) for at least one minute. It should be noted that the cooling period could take up to 30 minutes. Other point of use treatment options exist, such as hypochrlorite (bleach - regular unscented) treatment. For bleach, the label will say the active ingredient contains 6 or 8.25% sodium hypochlorite. For one gallon of water, use 8 drops if 6% or 6 drops if 82.5% bleach [1]. Another option is the use of iodine tablets (tetraglycine hydroperiodide) or specific filtration devices often referred to as backpacker water filters or purifiers (LifeStraw is an example). It should be noted that water filters physically strain out bacteria and protozoan cysts (such as Giardia) while water purifiers also combat viruses (which are more tiny). Ideally, a water purifer would be used.

Learn more about emergency disinfection of water at or


After a major earthquake or tsunami it is likely that sanitation resources will be damaged and inoperable. Immediate sanitation solutions are necessary to minimize the spread of disease. A simple option is the use of plastic bags inside disposable buckets for defecation and waste containment. Another option if plastic bags are not available is to create a trench latrine where waste is covered daily with soil. However, this is unsuitable where flooding has or could occur. Hand washing facilities should be put in place immediately, even if it is just access to soap and water in simple containers.

Medium Term

Mold & Mildew

One potential issue in the medium term is the development of mold and mildew due to water saturation in drywall, carpeting, furniture, and the like. For mold on wood or walls, a mixture of one cup of bleach to one gallon of water can be used. Mold can also be killed with ammonia, tea tree oil, vinegar, hydrogen peroxide, Borax, or baking soda. Detailed tips on how to kill mold can be found at

Structural Weakness and Safety of Buildings

Even if buildings are standing, individuals need to understand that it is very likely its structural integrity has been compromised from the massive forces placed on it. It is recommended that reinforcements be put in place to strengthen the building structure. It is also recommended that strong efforts be made to assess structural damage. A good resource to start with is the U.S. Occupational Safety and Health Administration's Guide for Assessment, Cleanup, and Repair of Structures

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