Water issues

Over its length, the PCT travels through a wide range of environments each of which presents unique water-related challenges.

Dealing with water

Too little water

There are long water-less stretches on the PCT. Sometimes, you’ll travel around 30 miles between water. Long dry stretches should only be attempted by knowledgeable, physically fit travelers who are carrying large amounts of water. Seasonal water sources, faucets and water tanks run dry. Water caches should never be depended upon. Dehydration, heat illness and hyponatremia are real threats on the PCT. Your safety is your responsibility. Dry stretches are not for everyone!

The PCT traveler faces long stretches without water and an incomplete picture of what’s available. Careful water planning is essential. In Southern California, always carry the latest PCT Water Report.

In Northern California and Oregon, the PCT travels through regions that alternate between having plenty of water and very little. The Hat Creek Rim in Northern California, for instance, is one of the longest dry sections of the entire trail with about 30 miles between reliable sources.

Too much water

The situation is starkly different in the Sierra Nevada. Early season travelers generally face a PCT that is at least partially covered in snow. The challenges presented border on mountaineering. One hiker described the experience as a “winter ice endurance event”. Snow travel requires skills, fitness, equipment and risk tolerance that is generally beyond the scope of normal backpacking.

Similarly, Washington and Oregon harbor dangerous snow slopes well into summer. Sometimes the situation is even more dangerous than on the famous Sierra passes.

Perhaps still more dangerous are the raging creeks that cross the trail during the spring. At the least, they can be terrifying. Creek crossings account for an uncomfortable number of “near miss” events where PCT hikers narrowly escape serious injury or death. Be prepared to turn around. Carry enough food for a change of plans and maps that show alternate routes.

Water quality

The best water is obtained from high alpine side streams or springs. Look for streams or creeks where no cattle, pack animals, or humans have traversed the watershed above the point of taking water.

Beware of algae

Innately, we are drawn to crystal clear water and tend to be suspicious of water colored with algae. This instinct is a good one. Algae are good markers of potentially unsafe drinking water, and algae-laden water can be dangerous even if filtered and purified. Toxins released by certain bacteria associated algae are not necessarily neutralized by today’s filters or purifiers and can cause illness. Algae are more commonly found in water that’s high in temperature and foam content, so be wary of warm, foamy water if you notice it. Also, all soaps and cleaners, even the supposedly environmentally-friendly and biodegradable ones, have substances that serve as algae growth factors. Use such products cautiously and use the tips below to be more hygienic as well as water-quality conscious when you’re in the backcountry.

Beware of feces

Of course, you already know this. But, do you realize how full of germs it can be? One cow, if infected with giardia, can produce enough cysts (over 100 million) in one day to infect the entire city of Los Angeles and then some. And, if that’s not bad enough, it can also be full of viruses (tiny microbes that are not removed by standard water filters) as well as bacteria. We are talking about some high risk contaminants. Be warned, a drink of untreated contaminated water could land you in a hospital intensive care unit with a potentially lethal infection.

Choose side streams and lake outlets

Odds are that you will find higher water quality if you fill your bottles from side streams and lake outlets. Side streams provide some of the backcountry’s safest water, but watch out for cows upstream as they can ruin even the purest source. Lake outlets are better than inlets because water flowing out of lakes has been exposed to extended periods of UV light, which kills micro-organisms. Another reason why outlets are better than inlets is because settling occurs in lakes such that “heavy” giardia and other micro-organisms sink to the bottom of the lake as water flows through it. Experiments done at the UC Davis Castle Lake Research Station verify these processes.

Protecting water quality

PCT enthusiasts can help preserve the water quality along the trail for fellow hikers as well as for the millions of people miles upon miles downstream whose water districts obtain their water from the mountains.

PCT hiker. Photo by Ron Kelley

Photo by Ron Kelley

1) Don’t use any type of soap (including the so-called biodegradable soaps) directly in the water. Soap contains many elements and substances that act as growth factors for algae. Overgrowth of algae is harmful in the environment and can choke-out oxygen required by other water-based species.

2) Don’t wash your dishes, yourself, or your clothes in lakes or streams. Many of the food particles on your dishes and even the sunscreen residues on your skin provide substrates for algae overgrowth. Rinse or wipe off your cook kit well away from streams or lakes. Consider bringing a collapsible  bucket (only 1-3 ounces of extra weight) to use for cleaning yourself, pots, and utensils at a safe distance from the trail.  This is in keeping with wilderness regulations that require that all dish washing be done at least 100 feet from any water source. There is a good rationale for this; distance allows nutrients to be filtered out by vegetation or soil before they reach water. In the same vein, even if you’re not using soap, clothes should never be rinsed in or near water as they can be a major source of nutrients for algae. It’s also best to rinse yourself off (to get off sunscreen, body oils, dirt, etc.) before you go for a swim. We recognize that these recommendations may seem a little draconian and may affect the spontaneity of a quick dip in the lake, but in the long-term they represent an investment in the quality of our trail water.

3) Dig your cat hole a good 100 feet (200 feet is even better) from water sources. Too many campers are defecating much too close to campsites, water, and trails. We recommend that hikers and campers head away at least 70 steps from their campsites and away from water before digging a small cat hole. And please carry out your toilet paper.

4) If you are a horseback rider or pack train leader, you can assist in preserving water quality by watching where your stock poop. Bring water to your animals, rather than have them drink directly from water sources — increasing the likelihood that they may also poop or urinate into the waterway. Manure on trails washes easily into streams during rain storms. If your animal poops within 100 feet of a stream or other water course, rake the manure into the ground where fungi can decompose it and neutralize its harmful components. The same goes for manure on the trail. Rake it or take it away from the trail tread to protect water quality.

Water treatment


For the long distance hiker, boiling drinking water can be impractical because it takes a long time and uses a fuel in the process. If you’re dealing with particularly gross water, or are cooking dinner with dirty water, you only need to bring the water to a boil. Once it has reached that stage, all of the micro-organisms have been killed. The elevations on the PCT are low enough that this is always the case. Note that boiling does not neutralize chemical pollutants.

Water Filters

The primary difference between a water filter and a water purifier is that a purifier adds another layer to the filtering process. This layer – generally an iodine mix – is designed to kill viruses.

When shopping for a water filter or water purifier, look for information on the type of contaminants that the device is effective against. It should include Giardia and bacteria and hopefully Cryptosporidium. If it also removes viruses, that’s even better.

Keep in mind that filters can and do break and/or clog, so if you’re planning on filtering, it would be wise to also carry some form of chemical treatment as a backup.

Chemical Water Treatment

Chemical treatment solutions are popular on the PCT because they are simple and lightweight.


Iodine in table form is probably the most widely available form of chemical treatment. The taste of iodine-tinged water takes some getting used to, but neutralizing tablets (which are added to the water after the iodine has been given time to do its work) can help remove the taste and color of iodine from the water before you drink it. Crushed vitamin C tablets will do the same thing.

As with filters, the effectiveness of the treatment varies with the turbidity of the water. So straining it first — through a bandana, coffee filter, etc. – will increase it’s effectiveness.

In addition, the temperature of the water affects chemical treatment. So the colder the water the slower the purification process or the more chemicals required. If the water is colder (as it usually is), you will need to let it sit longer – possibly overnight for cold stream water.

Iodine will not neutralize chemical toxins and there have been worries that long-term use of iodine may not be a good idea for people with thyroid conditions.

Chlorine dioxide

Stabilized Chlorine dioxide is sold under various brand names and is available in both solid and liquid forms. It contains no chlorine or iodine. Chlorine dioxide, according to Aquamira’s manufacturers, is an effective and safe water treatment used by municipal water treatment plants around the world. Like iodine, it is convenient for backpackers because it’s lightweight, compact and easy to use. Similarly, it’s effectiveness is hampered by cold and murky water.

Ultraviolet treatment

UV light-based electronic devices are another option. Like all other treatments, cloudy water and cold temperatures can be an issue. CR-123 batteries are available in most, but not all resupply locations.

Thanks to Robert W. Derlet, M.D., Dustin Ballard, M.D., George Durkee, NPS and Karen Berger for contributing to this page.

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