There are many different technologies involved in clean drinking water systems, and the many different systems available are divided not only by the types of filtration they use but also by whether they are designed to filter impurities out of mains water or used for portable water filtration.

Most natural water sources do not have water that is safe to drink, either due to pollution, human waste, microorganisms, pathogens or diseases, and over 2bn people in the world use a polluted water source of some kind, risking potentially deadly diseases in the process.

In some cases, setting up a mains filtration system is not always feasible, so a range of portable clean water solutions are available, often designed for situations where water filters have either stopped working or are otherwise unavailable such as when out camping.

Here are some examples of portable clean water solutions.

Portable Water Filters

A portable water filter can take many forms, but usually takes the form of either a water bottle or a straw, which when water enters it, uses a variety of physical filters (typically using carbon and ceramic filters, although others will use battery-powered UV light as well).

Typically they will use simple systems such as gravity, motion, water pressure or small pumps, although some systems are available with either a battery or a solar panel and will work more like miniaturised versions of mains water filter systems.

Some filters will simply make the water potable (safe to drink) whilst others will affect the taste as well.

Water Purification Tablets

Water purification tablets involve taking a litre or two of water from a natural, contaminated source, and then dropping a tablet into it, letting its active ingredients work to kill harmful bacteria and other pathogens.

There are typically three main ingredients used in water purification tablets, although sometimes other ingredients are included to help reduce or offset any aftertaste.

• Iodine – best used in warm water, iodine has been used for a very long time to purify water when on the move. Iodine typically requires warm water to work well and leaves a notable strong metallic aftertaste.
• Chlorine – Chlorination is a common way to purify drinking water at industrial scales, and it similarly works to combat viruses and bacteria, especially in the sodium-based tablet form you typically find chlorine in. It works with a lot of different types of water but leaves a strong bleach-like smell and chemical aftertaste.
• Chlorine Dioxide – More expensive than the other two types and requires as much as four hours to be effective, chlorine dioxide is more versatile and does not leave as much of an aftertaste.

UV Light Filter

Much like how ultraviolet light has become an increasingly popular solution, portable UV filters can simply be placed in a body of water and destroy the DNA of pathogens in seconds.

Whilst they are highly effective as the last part of a filtration system that had removed silt, sediment and anything that makes the water cloudy, large particles can hide pathogens inside in a way that the UV light cannot reach.