Water is purified in one of four ways in this system. The first by boiling on the stove, the second (8) by Katadyn tablets 7g, the third (9) by Premac's Travel Well Pocket pump 47g and the fourth (3) by my own designed gravity filter 48g (wet).

Water requirement for hot food and drinks works out at 2 litres a day, this will be drawn at camp or taken from a supply shortly before and is purified by heat. If time and weather allow, this water can be preheated in a pop bottle (7), half covered in sticky back plastic to aid solar absorbtion and therefore save on gas. Katadyn tablets will be used to treat cold water stored in a 2 litre Platypus bag (2), which then has the option of being filtered through my own gravity fed widget which is basically a short piece of hose filled with Brita water filter granules, obtained from a spare cartridge. Its a slow process but left over night it will fill a 2 litre container (4) hung from a walking pole (1). Hopefully this will reduce heavy metals and eliminate any bad tasting water but this is as yet untried and I'll report on it's effectiveness later. Another option to top up on the go is the Travel Well pump, kept handy I can fill a small container (6) as and when water is available on the trail. Lastly, Isotonic drinks powder (5) 395g is added to any drinking water as an alternative taste and also offer a quick energy boost.

The envisioned way this will work is that I shall be carrying 2 litres for that days consumption. As I drink this, any chance to top up with the mini pump will be taken, still carrying no more than 2 litres. Nearing the days projected end, it will be seen on the map whether the desired stopping point might have a water source. If it does I carry on and have no problem. If it does not then at a preceding source, I shall top up my 2 litre day container, plus fill another 2 litre for my cooking allowance. I then walk hopefully only a couple of miles with 4 litres. The day 2 litre then will filter overnight ready for the next day and so on.

Last minute changes have led to the 2 litre bottle (4) being replaced by a 2 litre Platypus. With all the air removed this becomes a sealed system preventing possible spills and contamination.

Post walk

The main lesson I have learned is that the value and importance of water cannot be under estimated. I did exactly this and paid the price by being dehydrated. Sourcing water in upland areas was least problematic but lowland farm land and populated areas had the possibility of high levels of Nitrates and microbiological content and seemed too risky.
I walked long distances with limited water during these times and developed a steady walking rhythm, breathing in and out through my nose, which greatly reduced usage by limiting evaporation surface area and recycling exhaled vapour. keeping cool and therefore limiting sweating was helped by thin cloud cover and windy days during the first week. As the weather warmed, water availability increased also allowing more uptake.

Problems occurred in limestone areas where water containing carbonic acid reacts with limestone and becomes hard. Calcium and magnesium bicarbonates are formed. I did suffer from trapped wind in these areas which made me feel slightly sick and off my food. The chemistry of the body is not my forte but their was definitely a PH imbalance going on here.

Heavy metal's including lead were a danger after leaving Richmond so I carried a surplus through this danger area.
All of the water I drank was treated in the ways outlined above, no untreated water was consumed and no upset stomach experienced. In hindsight I would have taken a more capable hand pump filter to allow for more reliable sourceing.

The plastic pop bottle was invaluable as it allowed filling from streams, which was not possible with the Platypus reservoirs. I did not find time to use it as a solar heater, however it did produce warm water on the odd occasion it was left full on my sack.

Measand Falls, Haweswater