Treating Water on the Appalachian Trail
Water is more prevalent on the Appalachian Trail than on some of the other long-distance trails in the country, but that doesn’t mean that the sources are clean. Treating water and having a reliable filter, chemical, or UV method is essential. Giardia can not only ruin your day but also your entire thru-hike.
Water is one of the most essential things to consider on a backpacking trip. Constantly monitoring the distance between sources and correctly treating water is one of the best ways to assure a successful and fun backpacking adventure on the Appalachian Trail. Numerous techniques and technologies exist in the water treatment space and we have compiled a list of the most common on the Appalachian Trail.
Water purification has changed and expanded dramatically over the years – boiling, filtration, ultraviolet light, and chemical treatment with iodine and chlorine are all effective. We have seen people hike the entire trail using steripens, iodine and other chemicals for purification despite filters being the most popular method.
| Water Treatment | Type | Weight | Price ($) | Output |
| Sawyer Squeeze | Squeeze filter | 3 ounces | 38.95 | 1.7 liters / minute |
| Sawyer Squeeze Mini | Squeeze filter | 2 ounces | 22.95 | 1 liter / minute |
| Aquamira | Chemical | Each bottle contains 1 fl. oz. | 14.95 | 30 gallons |
| Katadyn BeFree | Squeeze and bottle | 2.3 ounces | 49.95 | 2 liters / minute |
| Sawyer Micro | Squeeze filter | 2.5 ounces | 29.95 | 1 liter / 1.5 minutes |
| Iodine Tablets | Chemical | 3 ounces | 8.95 | 6.25 gallons |
| Platypus Gravity Filter | Gravity Filter | 10.9 ounces | 109.95 | 1.5 liters / minute |
| Katadyn Steripen | UV light | 6.3 ounces with batteries | 129.95 | 32 fl. oz. per 90 sec |
Our Choice: Sawyer Squeeze
The Sawyer Squeeze is among the most popular backpacking filters. It is compact, simple, lightweight, easy to use, and attachable to store-bought bottles. The versatility makes it great to depend on for months at a time. Using the provided bag to filter into a container or drink directly through the filter is possible and can make the Sawyer products more versatile.
The Sawyer filters adequately remove bacteria and protozoa from your water. However, the same can’t be said for viruses. But this isn’t often a concern in the backcountry.
What we like
- Reliable, inexpensive, simple, and easy to clean
- Packable and durable
- Versatile: can squeeze through or drink straight from the filter
- Instantly treats water
What we don’t
- Rubber O ring falls out with over-tightening
- Can freeze and crack in cold conditions
- Provided pouches do not perform very well
- Not effective against viruses
Sawyer Squeeze Mini
The Sawyer Squeeze Mini is another version of the Sawyer Squeeze above. It is more lightweight than the original Sawyer filter but also sacrifices the flow rate and the maximum filtering capacity. We have found the mini requires more frequent backflushing and after a couple of gallons of dirty water is filtered it slows its filtering rate considerably.
The Mini has a slow flow rate that only degrades over time. But, it is still good for shorter trip, we just don’t recommend it for a MINI ideal for shorter trips but less so on an entire AT hike. Pay extra and buy the original Sawyer Squeeze.
What we like
- Lightweight
- Small and packable
- Screws onto most standard water bottles
- Instantly treats water
What we don’t
- Slow flow rate
- Can easily Clog
- Many leaking issues were reported with included pouch
- Not effective against viruses
Aquamira – The Chemical Choice
Aquamira uses the chemical chlorine dioxide to treat water and kill pathogens. The two small bottles are very lightweight and easy to use. Aquamira treatment simply requires mixing eight drops from each bottle and then adding it to the untreated water. Then it takes 20 minutes for the Aquamira to kill all the maladies.
Contrary to other methods on the list, Aquamira is effective against viruses. It’s an inexpensive method costing only $15. However, the waiting time can be a frustration in dry areas. The Aquamira kit also does not remove sediments.
What we like
- Simple to use
- Kills viruses
- Small and compact
- Cheap
What we don’t
- Takes 20 minutes to work effectively
- Slightly changes the taste of the water
- Difficult to monitor the quantity left in the droppers
Katadyn BeFree – Good for day hikes or small amounts of filtering
The Katadyn BeFree is not a great system for a full thru-hike, but it is a good option for shorter backpacking trips and long days in the mountains. It is essentially a nozzle-based filter you can use with the included bottle or other compatible bottles.
The filter rate diminishes quickly over time and the Katadyn BeFree is not easy to clean. But, it is still a popular filter system for shorter hikes and backpacking trips where less water is required to be filtered.
What we like
- Simple and reliable
- Dependable bottle and easy to squeeze through
- Quick to use and easy to keep handy
What we don’t
- Clogs easily
- Difficult to clean
- Tough when filtering multiple liters at a time
Sawyer Micro
Sawyer created the Micro to be a lighter alternative to the original Sawyer Squeeze but with a faster flow than the Mini. The Micro is lightweight, reliable, and easy to use but still falls short of our top pick from Sawyer.
The Micro has a noticeably slower flow rate than the Sawyer Squeeze and seems to clog up easier but it is also a faster and more efficient filter than the Sawyer Squeeze Mini.
What we like
- Lighter weight and versatile
- Easy to clean and backflush
- Affordable and durable
What we don’t
- Slower flow rate than the Sawyer Squeeze
- Poor quality bag included from Sawyer
Iodine Tablets
What is the best thing about Iodine Tablets? They weigh almost nothing! So you aren’t taking on any extra weight. But, the benefits really end there.
It takes about 30 minutes for iodine tablets to be effective and even then there may be a strange taste. Sold separately are taste neutralizing pills that can be paired with Iodine. Another downside of this treatment method is that Iodine isn’t effective against cryptosporidium.
What we like
- Simple
- Lightweight
- Cheap
What we don’t
- Take 30 minutes
- Not the most effective treatment
- Leaves a funky taste in the water
Platypus Gravity Filter – A good group option
The Platypus Gravity Filter System has two bags and an inline filter. There is a bag for the dirty water (yet to be treated) and gravity forces the ‘bad water’ through the filter and into a clean bag. It is a simple set it and forget it method available in 2 and 4-liter capacities.
The Platypus Gravity Filter is great for groups and has a good flow rate. But, it’s heavy and bulky. The best feature is that the Gravity Filter does all the work.
What we like
- Efficiently filter large quantities
- Little work/effort required
What we don’t
- Heavy and Bulky
- Takes time for gravity to move the water through the system
Katadyn Steripen – The UV Option
The Katadyn Steripen is unique to this list because of its use of ultraviolet rays. The pen is effective against bacteria, fungi, and viruses. And the Katadyn Steripen uses UV rays. Simply fill a bottle with water, stir with the ultraviolet pen for 90 seconds, and you have clean water.
The UV Pen does not work well in cloudy or murky water and a prefilter through a bandana or other cloth may be required to assure it is effective. The Katadyn Steripen is lightweight and especially beneficial when viruses are a concern. Despite its ease of use, it is not one of the most commonly used methods on the Appalachian Trail.
What we like
- Lightweight
- Nearly instant (90 seconds)
- Kills viruses
What we don’t
- Requires Batteries
- Less durable than others on the list
- May need to prefilter murky water
