For decades, many people have taken tap water for granted. It is cheap, widely available, and reliable. Most people in the first world don’t think about what’s behind the tap when they turn it on, and they never think about waterborne diseases such as cholera or dysentery. Those are third-world problems, and they can always be traced back to inadequate water supply solutions.

But increasingly, mismanagement by local authorities, cruel edicts from privatized water companies and natural disasters have shown that it simply isn’t possible to rely on tap water in all cases.

Again and again, water companies have shown disdain for public health by refusing to implement even standard measures of quality, often not upgrading pipes or neglecting to include enough chlorine. Private authorities are even worse, permitting tap water utilities to decay into dust while ratcheting up the fees year after year. Bottled water is sometimes a solution, but increasingly it has become so expensive and produces so much waste in empty bottles that it is a worse option than all but the nastiest tap.

While the first world is working hard to force their governments to consider water a right instead of a privilege, companies, missions and persons who live in the third world are increasingly relying on methods of chlorinating their own water. Because the mixture needs to be strong enough to kill microbes but weak enough to not harm the user, often a dosing unit is used.

These machines will automatically add chlorine to water as it is pumped through them, killing any microbes that may survive the filtering process. Dosing units are increasingly being used by persons who live in extremely remote locations and must use well water, or by persons who are working in the third world.

Portable dosing units were developed for military applications as far back as the 1940s, but modern dosing units are designed to be simple and easy enough for civilian use. While they cost hundreds or even thousands of dollars, they can convert any filtered water source into potable water at a steady rate, requiring only electrical power. Advanced portable dosing units can even supplement or make up for a lack of proper water delivery systems, being able to tap into existing pipes and provide chlorine.

This makes them a must-have for any disaster relief group or public safety agency, since if a water treatment plant is taken offline then water can still be dosed and delivered while it is being repaired.

The most rugged of portable dosing units may in fact include battery power and filtering units, making them the ideal solution for scientists or humanitarians who are working in rough field conditions and thus need to turn local water into drinkable water. Such units are also an essential item for persons living in earthquake prone areas, since earthquakes are notorious for ripping up water pipes and forcing residents to live off of reserves or locally available springs.

These units have proven themselves invaluable in Haiti and Chile in recent months, and any humanitarian organization seeking to visit those locations should purchase dosing units before departure.