While hiking, it is important to adequately prepare clean drinking water by carrying a water notification system for the trip, as drinking straight from natural sources may send bacteria and other diseases into the body.

There are different types of water purification systems. Some may be filters, purifiers, or a combination of both. Water is cleaned with a purifier through chemicals (mostly iodine or chlorine) that kill every bacteria and virus in the collected water.

Water is cleaned in the filter water cleansing system by sieving water through a filter with very small holes. This can remove dirt and bacteria but is not very effective against viruses. However, this is the more popular water filtration system used in America despite this defect. There are also purification systems that combine both features of a purifier and filter.

In choosing a water purification system, the hiker needs to understand the different filters on the market. The most common filter system is the pump filter. It works by pumping dirty water from a source and pushing it into a clean bottle through a filter. The pump filter is easily replaceable and can easily get water from streams or puddles. It is compact and can be easily carried in a backpack. However, it is slightly heavy, needs a good amount of force to pump water, and must be constantly cleaned to provide clean filtration.

There are also gravity filters, which are operated by using an attached bag to collect water, then letting gravity pull the water down through the filter and into a clean compartment. No pumping is necessary; one can hang the bag on a higher surface, like a tree, and let gravity do the rest. However, the gravity method is slow, and it is also difficult to collect water from a small source, unlike the pump filter. The filter must also be regularly cleaned to ensure proper filtration.

Another type of water filter used is the squeeze and bottle filter. The hiker fills a bottle or bag with water then squeezes the water through a filter and out of the container. The hiker can then drink the clean water immediately. Some of these squeeze and bottle filters also act as gravity filters. These filters are light and compact and are not too pricey.

The most commonly used form of water purification are chemicals to treat the water. It is a very easy-to-use system and is advisable for every hiker to carry as a backup to any other filtration system they may have. These chemicals come in pills, mixes, or drops that the hiker can add to the water, then drink from after a couple of minutes has passed to let the chemicals enter the water and kill all the germs and viruses properly. The downside is that they take a long time to purify the water, some taking as long as 1 hour. The hiker is also left with metallic-tasting water, and this system is not safe for those with thyroid disorders.