Safe Drinking Water in the Backcountry, Part 2: Filtration

Saint Mary Falls, Glacier National Park

In my previous post on using bleach to treat water in the backcountry, I said my method for treating water is a combination of household bleach and an inline filter. You might be wondering why I would use both. Especially since most people only use one or the other and some don't treat their water at all... read more >

Water in the backcountry is much cleaner than what most people would expect, especially at high elevations, but even if the risk of infection is small, there is still a risk. Even experienced backpackers know it isn't always easy to find a good water source, and equip themselves with some kind of water treatment method.

A common reason people give for not treating their water is that they have been drinking it their whole life and so are immune to pathogens. This is not entirely true and more a testament to how rare infections are with experienced backpackers than anyone having a super-human immune system. For example, it is highly unlikely that you will ever become immune to Giardia, the most common water-borne pathogen in the backcountry. Giardia requires repeated infections to acquire any measure of immunity, and even then, your chance of carrying it without symptoms is less than 10%. You can get Giardia again and again and again.

Another reason I've heard, is that chemical treatments are more harmful. This is also not always true if proper chemical treatments are used correctly. This is also not a good argument for not taking a water filter.

I met four people who have contracted Giardia, and one person who got it twice. The consensus seems to be that the minor inconvenience of treating water is better than 2-4 weeks of nausea, fatigue, cramps, and the never-popular explosive diarrhea. Also, consider the fact that you're in the backcountry with no indoor plumbing and a limited toilet paper supply... Water treatment can be as lightweight as 1 ounce, as cheap as $1, and as small as a 1-ounce eyedropper of bleach, so it's worth taking.

If I was only going to take one treatment method, it would be a .1 micron inline or straw filter every time, but below are good arguments for carrying both.

1. It's good to have a backup method... read more >
   
   
   In over 3,000 trail miles, I have both lost and broken a filter. I have also discovered too late that a filter did not work (a few miles into my hike to Mount Katahdin). I have run out of chemical treatments before reaching a resupply town and have forgotten it altogether. These are enough reasons for me to have a backup method, especially when the methods are so lightweight. Bleach 1 ounce, filter 3 ounces.
   
   
2. Filters allow me to drink up at the source and carry less... read more >
   
   
   When water is plentiful, and I have a filter, I've noticed I carry 16 fewer ounces when I leave a water source. It's because I can drink all I want immediately from the source without waiting for chemical treatments to be effective (usually 30 minutes). And since inline/straw filters are so easy to use, I don't mind stopping multiple times to get water. I don't even have to take off my pack.
   
   The heaviest filter I own is a Katadyn Hiker Pro at 12 ounces, so the lighter weight of only carrying a chemical treatment ends up not being much an advantage.
   
   Also, the water is typically colder at the source than it will be thirty minutes after a bleach treatment. This is appreciated on a hot day.
   
   
3. An eyedropper of bleach only weighs 1 ounce, so even though I prefer an inline or straw filter, 1 ounce isn't a noticeable addition to my pack.
4. Filters, unlike any chemical treatment, are very effective at removing Cryptosporidium and Giardia, the two most common water-born illnesses in American backcountry... read more >
   
   
   Both of these protozoans live in a cyst, which help protect them from chemical treatments. Filters less than or equal to 1 micron can easily remove them.
   
   
5. Bleach is very effective at removing viruses and bacteria, filters are not... read more >
   
   
   Most filters cannot remove viruses, and only filters less than or equal to .1 micron can remove bacteria. Chemical treatments, such as bleach, can easily kill both.
   
   
6. Bleach can be used to sterilize my toothbrush and eating utensil... read more >
   
   
   Add 4-5 drops per 8 ounces of water in your cook pot and soak for 30 minutes. Every thru-hiker knows how nasty a toothbrush can get after weeks in the backcountry.
   
   
7. Filters improve taste... read more >
   
   
   Some water just tastes bad before or after chemical filtration. Additionally, if the water is already very clean before a chemical treatment, or if you over treat it, you may taste the chemical in your water. Think of chemical treatments as adding an army of soldiers to your water to do battle. They kill organisms, but die in the process. The more organisms there are to kill, the more soldiers you need. If you add more troops than you need, you might get a stronger chemical taste. The filter helps this.
   
   

My preferred filter:

Sawyer Squeeze Filter

With the variety of filters on the market, I haven't found a good reason to continue using my traditional pump-style filter. If I can help it, I'd rather not get down on my knees, dangle a filter hose in water, and pump it into a bottle. I prefer inline or straw filters.

4-Way Filter Bottle

Rather than pump water through the filter, an inline or straw filter uses your suction to filter as you sip. You can just scoop and go, without having to take off your pack. And to fill a cook pot, you can use gravity or squeeze the water from the pouch or bottle.

When on a trail with plenty of water sources, it's not inconvenient to get water, so I don't carry around as much water weight. In addition, the inline filters themselves are also lighter than a pump filter. My favorite inline/straw filter is the Sawyer Squeeze Filter or the Sawyer 4-Way Filter Bottle. Here is why:

1. They have a .1 micron filter... read more >
   
   A .1 micron filter will remove 99.99999% of protozoa/cysts, like Giardia and Cryptosporidium, and bacteria, like e.coli.
   
   
2. Multiple ways to use... read more >
   
   
   In addition to the water pouches that come with the Squeeze Filter, you can attach it to most threaded soda or water bottles including 2-liter bottles. This is how I usually use it. The 4-Way Filter Bottle can be attached to wide-mouth bottles like a Nalgene bottle. The 4-Way Filter, and the squeeze filter with the optional attachment, can also connect it to a hydration bladder hose and used as an inline filter.
   
   
3. Easy to use... read more >
   
   
   Fill up your pouch, bottle, or hydration bladder at the water source, attach the filter, and drink. No waiting, no pumping, and if you can reach your water container with your pack on, there's no need to take your pack off. This convenience means I'll stop more frequently for water, and carry less water weight.
   
   With both filters, you can also squeeze the water directly into a cook pot, unlike other filter straws.
   
   
4. Small and Lightweight. The Squeeze filter with a pouch weighs about 3 ounces, the 4-Way Bottle, about 5.
5. Sawyer has a one million gallon guarantee!... read more >
   
   
   I was skeptical, so I contacted Sawyer. Since most filters quit after a couple hundred gallons, this is essentially an attention-grabbing way of saying it has a lifetime guarantee on the filter element. The guarantee does not include the filter's housing or water pouches, which doesn't concern me since the filter has no moving parts, it's not that easy to break. Also, since the filters can be screwed onto soda bottles or Nalgene bottles, broken pouches or bottles are cheap fixes.
   
   
6. Easy to clean/backwash... read more >
   
   
   The Squeeze Filter comes with a syringe so you can easily backwash all the collected muck in the filter. This is one of the reasons it lasts for 1 million gallons. The 4-Way Bottle comes with a sink attachment to do the same.
   
   
7. Cons, because there is always one, right?... read more >
   
   
   The hollow fiber filter in Sawyer filters, can break if frozen, so if it is below freezing, you will want to keep it in your pocket during the day and in your sleeping bag at night. Damage from freezing is not covered under Sawyer's 1 million gallon guarantee. The worst of it is, you won't even know if it's not working. If you suspect it was frozen, you'll have to just throw it away.
   
   Some users have had problems with the water pouches that come with the Squeeze Filter ripping open. The pouches are holding up just fine for me so far, but I didn't purchase this filter for the pouches. And I prefer using plastic soda or water bottles anyway... read more >

1. I carry 2-3 plastic water bottles. One 16 oz and one or two 32 oz. That way, I can lose or break a bottle and still have a way to transport water. A hiker with a dog came to my shelter on the Long Trail in Vermont, and the dog decided one of my water bottles was a fun chew toy. I'm glad I had a backup.
    
2. Plastic soda/water/gatorade bottles are free, lighter than Nalgene or aluminum bottles, and they are readily available and otherwise destined for a landfill. One argument I've heard for not reusing plastic soda bottles is that they release dioxins in your water. This is an urban legend. There are no dioxins in plastic soda bottles. That being said, a group of chemicals called phthalates are sometimes added to plastics to make them flexible and less brittle. These can leach into water if you heat up the plastic. I don't cook with them, so I'm not worried about this. (Reference)
   
   Another reason I've heard, for not reusing plastic soda bottles, is that bacteria can develop under the cap, but these get cleaned regularly during my bleach treatment, so I'm not concerned about that. If you know of any other reasons I shouldn't reuse soda bottles, please let me know at grayson.ryan@gmail.com.
    
3. Nalgene and other hard plastic or aluminum bottles cannot be squeezed to fill my cook pot with the Squeeze Filter. Or to get all the air out to treat the cap and threads when chemically treating the water.
    
4. I've never been a fan of hydration bladders, since they are difficult to get in and out of my backpack, hard to see how much water you have left, and not easy to attach to the outside of any of my packs.

At the time of this post, Amazon is selling the Sawyer Squeeze Water Filter for $42.38 (Click here to order or read more reviews). For that price, you will get: three lightweight collapsible pouches (0.5 L , 1 L, and 2 L pouch), Sawyer 0.10 Absolute Micron Hollow Fiber Membrane Screw On/Off Water Filter, Replaceable Pop Up Drinking Spout, Cleaning Syringe, and the 1 Million Gallons Guarantee.

The 4-Way Filter Bottle is currently $36.86 at Amazon (Click here to order or read more reviews). For that price, you will get: a 1L water bottle, Sawyer 0.10 Absolute Micron Hollow Fiber Filter, faucet attachment for backwashing, extra straws, hose adapter for hydration bladders, and the 1 Million Gallons Guarantee.

See the Sawyer Squeeze Filter in action:

See the Sawyer 4-Way Filter Bottle in action:

More water related information:

Why I don't use Sterilizing Pens... read more >

1. I've seen them fail on other hikers more often than I've seen them work.
2. Must use lithium batteries, which are hard to find in small resupply towns. If alkaline batteries are used, you can usually expect to only treat 2-8 quarts, whereas Lithium may last up to 100 quarts.
3. Not as effective if water is cloudy or discolored.
4. Can leave threads of cap untreated.
5. Heavier than my bleach/straw method.
6. Expensive.

 
How much water to carry... read more >

It varies from person to person and depends heavily on the outdoor temperature, but the rule of thumb is: Drink 1/2 to 1 quart of water per hour of hiking. On a hot day climbing up a mountain, your body can lose 1 - 2 quarts per hour from perspiration. It's pretty simple though, if you feel thirsty, drink.

One way to determine how much water you are losing during exercise, is to weigh yourself before and after a hike or workout. Subtract about 7% from the difference in pounds (to account for the burned calories), then multiply by 16. That's about how many ounces of water you need to replace. 

Using Bleach To Treat Water in the Backcountry... read more >

Why I use plastic soda or water bottles... read more >

1. I carry 2-3 plastic water bottles. One 16 oz and one or two 32 oz. That way, I can lose or break a bottle and still have a way to transport water. A hiker with a dog came to my shelter on the Long Trail in Vermont, and the dog decided one of my water bottles was a fun chew toy. I'm glad I had a backup.
    
2. Plastic soda/water/gatorade bottles are free, lighter than Nalgene or aluminum bottles, and they are readily available and otherwise destined for a landfill. One argument I've heard for not reusing plastic soda bottles is that they release dioxins in your water. This is an urban legend. There are no dioxins in plastic soda bottles. That being said, a group of chemicals called phthalates are sometimes added to plastics to make them flexible and less brittle. These can leach into water if you heat up the plastic. I don't cook with them, so I'm not worried about this. (Reference)
   
   Another reason I've heard, for not reusing plastic soda bottles, is that bacteria can develop under the cap, but these get cleaned regularly during my bleach treatment, so I'm not concerned about that. If you know of any other reasons I shouldn't reuse soda bottles, please let me know at grayson.ryan@gmail.com.
    
3. Nalgene and other hard plastic or aluminum bottles cannot be squeezed to fill my cook pot with the Squeeze Filter. Or to get all the air out to treat the cap and threads when chemically treating the water.
    
4. I've never been a fan of hydration bladders, since they are difficult to get in and out of my backpack, hard to see how much water you have left, and not easy to attach to the outside of any of my packs.

Safe Drinking Water in the Backcountry, Part 1: Using Bleach

Click here to skip right to my method for treating water in the backcountry with household bleach. If you're like me, you hate reading through a lot of unnecessary paragraphs when you're looking for specific information, and I can be unnecessarily long-winded. Here's proof...

- - - 

As many of you know, this blog has primarily been a place to share stories and photos from my trips, but my next trip won’t be for at least a couple months. So until that time comes, my blog will be more of a practical guide to backpacking. Or with the direction my life has taken, a practical guide for the deliberately homeless.

Either way, I've learned a lot from my experiences and I love to chat about this stuff. I get a lot of questions and could spend hours answering them, as many unfortunate people have realized after asking me a seemingly simple question.

Many of the questions I get involve obtaining safe drinking water in the backcountry. When I tell people I use common household bleach, they often look at me like I have a death wish. So that's where I'll start.

Few things are as refreshing as drinking all-natural water straight from a cold mountain stream, untainted by chemical treatments. Or to just plunge your face into a spring on a hot day and quench your thirst without fussing around with filters, pumps, and hoses.

If you are smart about choosing your water source, you could go for days, weeks, or even years without treating your water and never get sick. It's a gamble, but after spending a few days stepping over moose poop, or seeing a bloated dead animal floating in a water source, or worse yet, having to witness your friend doubled over with stomach pains and running off into the trees to decorate that beautiful foliage in vomit or explosive diarrhea... I'm getting a bit off the rails here... what I'm trying to say is, that stuff kind of diminishes the "all-natural" romanticism of drinking from a cold mountain stream. So, I treat my water.

Everyone has their own preferred method, but here’s what I do:

My Water Treatment Method:
My method for treating drinking water in the backcountry is a combination of household bleach (one drop per 16 oz.) and/or an inline or straw filter. And don't forget the often skipped step of cleaning your hands after touching potentially contaminated water. I carry a small bottle of hand sanitizer for this. Not doing so could negate everything you do to treat your water.

First, I should say that nothing is more effective as boiling to treat water in the backcountry. Boiling water vigorously for 60 seconds, or three minutes at altitudes higher than 6,500 feet, will kill everything. No other safe chemical or filtration method can claim that. If you're already boiling water for cooking, it's great. For drinking water, however, it is perhaps the most impractical method... read more >

It goes without saying that after boiling, drinking water is an unrefreshing temperature, and by unrefreshing I mean painfully scalding. Then it can stay warm for hours. Boiling is time consuming and wastes a lot of fuel, unless you do it at night on your campfire (assuming campfires are allowed where you're hiking), but then you'll have to carry an entire day's worth of water the next day. It's just too impractical to solely rely on boiling for safe drinking water, so I use bleach and a lightweight inline or straw filter

.
Why I use bleach:

1. It's safe... read more >

Ingesting enough undiluted bleach is most definitely toxic, but according to the Centers for Disease Control, even in cases where household bleach was accidentally ingested undiluted, there have only been minor cases of negative health effects reported. Due to the horrible taste of undiluted bleach, it's unlikely that someone could accidentally ingest a dangerous amount. And since I only carry one ounce into the woods, which I heavily dilute over the course of a couple weeks, there's little I could do to harm myself with it.

Bleach is also safe for the environment. If you accidentally spill some, it will dissipate in a few hours. It is also safe to dump unused bleach down a drain which leads to a municipal water treatment facility.

2. It's effective... read more >

While chemical treatments will kill most things in the water, none kill everything. And none work as well on protozoa, like Giardia and Cryptosporidium, as boiling and filtering. Bleach, however, is just as effective at killing protozoa, bacteria, and viruses as iodine, and nearly as effective as Chlorine Dioxide treatments, such as AquaMira.

I can also add 4-5 drops of bleach to 8 ounces of water in a cook pot to sterilize my toothbrush, eating utensil, trekking pole handles (to keep deer away), and cook pot. And every thru-hiker, who lives for weeks without running water, knows how important it becomes to keep your toothbrush clean.

3. It's cheap... read more >

Other chemical treatments will run about $10-15 to treat up to 30 gallons of water. A gallon of bleach runs about two bucks. The most I ever paid for bleach was in a small gas station near the Long Trail in Vermont, $3 for a half gallon.

If stored at room temperature, bleach will last for 3-5 months from the day it's delivered to a store and a gallon will treat over 3,000 gallons of water. If the bottle is kept closed when not in use, the biggest factor that will shorten shelf-life is the storage temperature. That is because sodium hypochlorite, the active chemical in household bleach, breaks down quicker in higher temperatures. According to Clorox, the amount of sodium hypochlorite they add to their bleach depends on the season. They add more in the summer to compensate for the higher temperatures. Check your label. 6% hypochlorite is the norm, and the amount my recommendations below are based on. A higher concentration will last longer before it has broken down to ineffective levels.

4. It's easy to find... read more >

I've never had a problem finding bleach in a resupply town, regardless of size and remoteness. Most gas stations on the outskirts of town also carry it. I have had trouble finding other chemical treatments, however. That's why I tried bleach for the first time. I was in a decent sized town, but nobody sold iodine or chlorine dioxide-based treatments.

I should also mention that if you're resupplying during a long distance hike, it is safe to dump what you don't use down a sink or toilet. Actually, it will clean pipes and keep them clear. It's also safe on a city's sewage system. If it's going to a septic tank, however, it could kill the bacteria needed for a septic tank to work properly.

5. It's lightweight... read more >

A one ounce eyedropper bottle full of bleach weighs about 1 ounce and lasts about two or three weeks on the trail.

How I use bleach:

My method is based on recommendations by the Centers for Disease Control, the American Red Cross, and hours of additional reading. If you find any mistakes or have questions or suggestions, please contact me at grayson.ryan@gmail.com. I will always be happy to learn something new and will update this information accordingly.

	1. Fill an eyedropper with bleach. Before heading out, I fill an eyedropper bottle with common household bleach. I use an old Visine bottle or breath drops bottle. Since bleach will degrade in direct UV light and become less effective, consider covering the bottle in duct tape, or paint, or something. To fill the bottle without spilling bleach, I often use a ZipLoc bag as a funnel. Put the desired amount of bleach in the bag. Hold it by one of the top corners, so one of the bottom corners is above the bleach. Cut a tiny bit of the corners off, then tip the bag and pour the thin stream of bleach into the dropper bottle. I keep the bottle in a ZipLoc freezer bag or in an empty wide-mouth Gatorade or Powerade bottle to prevent damage to gear and clothes. So far, I have not had a problem. Also, keep in mind, the decomposition rate of bleach increases by a factor of 3.5 for every 18° F increase in temperature, so if not stored at 60-80 degrees, it's probably a good idea to dump it out and replace it after a couple weeks to be safe.
	2. Fill your water bottle with water. The best water source is actually the top few inches of lake water. The longer time under the sun’s UV rays does a lot of the sterilization for you. Otherwise, a spring or swift moving creek will be fine. If the water source is not clear, I tie a bandanna around the top of my bottle when filling. If your water is still cloudy, let it sit until all sediment has settled, then pour the clear water into another bottle before treating. Chemical treatments are much less effective if the water is not clear or contains free-floating organic material. Organisms that are clinging to free-floating particles are harder to kill.
	3. Add one drop of bleach per 16 oz. of clear water. Use two drops if the water is really cold, cloudy, or discolored. If your bleach is not the common 4-6% solution of sodium hydrochlorite you may have to use more or less. The amount of sodium hypochlorite added to bleach may depend on the season. More may be added in the summer to compensate for the higher temperatures. It could be as high as 10%, so check your bleach bottle’s label and adjust dosage accordingly.
	4. Shake it like a Polaroid.
	5. Screw the cap nearly all the way on, then squeeze the bottle until it starts to pour out, and then tighten the lid. This ensures that the entire bottle, including the cap and threads, get disinfected.
	6. Wait 30 minutes. And in the meantime, clean your hands with a hand sanitizer. Not cleaning your hands after touching a contaminated water source could negate everything you have done to prevent a water-borne illness. If after 30 minutes, your water does not have a slight chlorine smell similar to municipal tap water, repeat steps 3 through 5. Think of bleach as an army of soldiers you're sending into battle. They kill organisms, but die in the process. The more organisms there are to kill, the more soldiers you need. That's why it may be necessary to treat a second time. And why sometimes you'll smell or taste more chlorine than other times. Keep in mind though, this isn't the fault of bleach alone. It's true for any chemical treatment.

More water related information:

Why I don't use Sterilizing Pens... read more >

1. I've seen them fail on other hikers more often than I've seen them work.
2. Must use lithium batteries, which are hard to find in small resupply towns. If alkaline batteries are used, you can usually expect to only treat 2-8 quarts, whereas Lithium may last up to 100 quarts.
3. Not as effective if water is cloudy or discolored.
4. Can leave threads of cap untreated.
5. Heavier than my bleach/straw method.
6. Expensive.

 
How much water to carry... read more >

It varies from person to person and depends heavily on the outdoor temperature, but the rule of thumb is: Drink 1/2 to 1 quart of water per hour of hiking. On a hot day climbing up a mountain, your body can lose 1 - 2 quarts per hour from perspiration. It's pretty simple though, if you feel thirsty, drink.

One way to determine how much water you are losing during exercise, is to weigh yourself before and after a hike or workout. Subtract about 7% from the difference in pounds (to account for the burned calories), then multiply by 16. That's about how many ounces of water you need to replace. 

Using Filters To Treat Water in the Backcountry... read more >

Why I use plastic soda or water bottles... read more >

1. I carry 2-3 plastic water bottles. One 16 oz and one or two 32 oz. That way, I can lose or break a bottle and still have a way to transport water. A hiker with a dog came to my shelter on the Long Trail in Vermont, and the dog decided one of my water bottles was a fun chew toy. I'm glad I had a backup.
    
2. Plastic soda/water/gatorade bottles are free, lighter than Nalgene or aluminum bottles, and they are readily available and otherwise destined for a landfill. One argument I've heard for not reusing plastic soda bottles is that they release dioxins in your water. This is an urban legend. There are no dioxins in plastic soda bottles. That being said, a group of chemicals called phthalates are sometimes added to plastics to make them flexible and less brittle. These can leach into water if you heat up the plastic. I don't cook with them, so I'm not worried about this. (Reference)
   
   Another reason I've heard, for not reusing plastic soda bottles, is that bacteria can develop under the cap, but these get cleaned regularly during my bleach treatment, so I'm not concerned about that. And it's just as much a problem with Nalgene or Aluminum Bottles.
    
3. Nalgene and other hard plastic or aluminum bottles cannot be squeezed to fill my cook pot with the Squeeze Filter. Or to get all the air out to treat the cap and threads when chemically treating the water.
    
4. I've never been a fan of hydration bladders, since they are difficult to get in and out of my backpack, hard to see how much water you have left, and not easy to attach to the outside of any of my packs.