A water filter or purifier offers peace of mind no matter the source of your water.
Water-borne hazards
New Zealand backcountry streams are reasonably healthy. That said, there is still a risk that water-borne illnesses like giardia, campylobacter, salmonella and E. coli can be picked up. The risk closer to home increases after a disaster like an earthquake or when travelling to developing nations, where viruses and bacteria pervade waterways.
Filters
Filters are the first line of defence against larger-than-a-virus protozoa and cryptosporidia such as giardia lamblia and parvum. They remove sediment and organisms down to 0.4-0.1 microns.
Purifiers
Purifiers kill the much smaller viral and bacterial organisms. UV light is the most common and effective form of purification.
The full system
Some systems use both a filter and purifier. The filter removes large particles down to 0.2 or 0.1 micron and the purifier deals with anything smaller. Unless the removal or treatment of water is at least 99.9%, there is a risk of infection.
Flow rates
The usual flow (or purification) rate is one to two litres per minute. It’s important to keep filters clean and free of sediment to ensure the flow rate remains high.
Where to filter
Always check – if possible – what’s in the water upstream to avoid contamination. Giardia slowly sinks, so draw your water where the flow is slow moving, away from the bank. Avoid muddy water as it can contain bacteria stirred up from the streambed and sediment will also clog filters.
Cleaning
Filters can be easily cleaned in the field, to ensure long life.
Now you know what to look for, it’s time to choose your filter or purifier…
SteriPEN Adventurer Opti $219.95 |
MSR Guardian Purifier $699.99 |
SteriPEN Quantum RPS $199.95 |
MSR MiniWorks EX $229.99 |
SteriPEN Classic 3 $169.95 |
MSR TrailShot MicroFilter $129.99 |