Drinking Water

Change Your Expectations

Have you already hiked the PCT or the AT? Then you'll need to change your expectations about drinking water sources on the Florida Trail. On the PCT, we have seen hikers grimace at the water pooling in troughs from piped springs — filled as they were with wriggling mosquito larva, algae, dead leaves, et cetera. Rather than scoop and filter this water, they filled bottles directly from the trickling pipe embedded in the rock. On the AT we have seen a lot of hikers drink directly from springs without filtering or treating the water first, convinced it was safe because it flowed directly from the living rock.


No water source on the Florida Trail will resemble the clear mountain springs and springs found along the PCT and AT. The "dirty" water that disgusts some hikers on the PCT is the norm on the FT. Acceptance of this fact will be important to enjoying your thru-hike.


So here's the bad news:  Since there are no mountains, the Florida Trail cannot isolate hikers from pollutants that accumulate in valleys by keeping them high along ridgelines and so forth, and due to Florida's flat topography, few bodies of water are safe from exposure to agricultural and other runoff. The Florida Trail passes many bodies of water that are polluted, and hikers need to be able to assess whether a water source is safe or not. Our guidelines to help you do that are below.


The general rule of thumb:

  • good — swamps, marshes, cypress domes, springs, sinkholes, small ponds, small streams and creeks, man-made wells
  • bad — lakes, rivers, canals, ditches, retention ponds, anything near a road, creeks influenced by tides

The Bad: Lakes, Rivers, Canals

Citrus groves and cattle pastures dump pesticides, herbicides, and fertilizers into creeks and rivers. Rain washes oil and other petrochemicals from highways into watersheds. Over-fertilized suburban lawns pour tons of fertilizers into waterways, causing persistently high levels of algae, which smothers aquatic plants and causes water to have a milky-green color.


Water filtration systems for backpackers cannot remove these chemicals. Assume that all lakes, large ponds, rivers, and canals are heavily polluted and thus off limits as drinking water sources. In our opinion, the most polluted waters on-trail are:

  • canals within the Everglades Agricultural Area (lands between the Seminole reservation and Clewiston)
  • Lake Okeechobee
  • the Kissimmee River

All that aside, let's keep it 100. Will drinking water contaminated with fertilizers, pesticides, and more kill you? Not instantly, of course. Because we were in a pinch, we have drank from ditches and agricultural canals in the past. We're still alive. But nitrates from nitrogen fertilizers may cause cancer. The long term effects of drinking this kind of contaminated water are not known, since so few people drink such bad water. The NIH article cited above discusses ground  water contamination, which is much less concentrated than surface water. Don't risk it.

More Bad: Saltwater Encroachment

In the St. Marks National Wildlife Refuge, almost all of the water sources are brackish (miles __ to ___ ). This includes the sources listed as drinking water in both the FTA databook and the Friend & Keatley guidebook. We were surprised and upset to discover this, since we were relying on these sources during our thru-hike. The creeks at ____ campsite rise and fall with the tides. The pond at _____ campsite is brackish, the many marshes built by the CCC look fresh but are in fact brackish, and even the ______ Spring has a sour, salty taste.

Can you drink brackish water? After all, it's not as salty as seawater. Isn't it just fresh water with electrolytes? A kind of natural Gatorade? Maybe. Take a look at the chart though, and you will notice that Gatorade is still technically "fresh" despite its electrolytes.

The salinity of municipal water is kept incredibly low, about 20mg/L. Finding hard data about the safety of drinking brackish water is nearly impossible. No government publication we can find discusses the issue.

Salinity Levels

milligrams per liter



brackish water

500 – 30,000


less than 500





human sweat

900 - 1400

human blood


“salty taste” according to US EPA


“salty taste” according to government of Western Australia


An interesting article from Slate in 2005 asked whether people in post-Katrina New Orleans should drink the brackish floodwater to prevent death from dehydration. It claims salt at concentrations of around 5000mg/L (5 parts per thousand) or less are safe to drink and even help the body retain water and prevent dehydration, while salt concentrations of 8000mg/L cause dehydration.


If true, that's interesting. But the window of safety there is pretty small, and we doubt anyone could taste the difference between 5000mg/L and 8000mg/L.


The trouble with drinking saltwater was stated most succinctly by NOAA: "Human kidneys can only make urine that is less salty than salt water. Therefore, to get rid of all the excess salt taken in by drinking seawater, you have to urinate more water than you drank. Eventually, you die of dehydration even as you become thirstier."


The bottom line is, you have to carry in all your fresh water for the stretch through St. Marks, beginning at mile JR's Aucilla River Store and ending at the town of St. Marks.

The Good: Swamps, Cypress Domes, Springs, Creeks, Wells

Swamp Water — You'll Like the Taste

There are two kinds of swamps: clear and black. To the surprise of many, the water in Big Cypress Swamp is crystal clear. It defies every expectation of what a swamp should be — dark, mysterious, foreboding. The other great swamp tromp of the FT, Bradwell Bay Wilderness, conforms to our imagination with its dense walls of titi bush and black water.


Swamps are great natural filters and purifiers of water contaminated with artificial chemicals and other pollutants. Whether in Big Cypress, the Green Swamp (on the western spur), the Bradwell Bay, or the prairies of Ocala NF, swamp water is safe to drink once it has been filtered. 


The dark water of Bradwell Bay, as well as most Florida rivers and lakes, is caused by tannins from tree leaves, the same tanic acids that give coffee and tea their brown color. Even after filtering, these tannins remain dissolved in the water, tinting it a range of colors from golden to dark brown. This tannin-tinted water is safe to drink. Sometimes it even tastes like tea and has a slight sweetness.


There are lots of places people might call "swampy" that aren't real swamps, however. Mucky pools, drainage ditches, retention ponds collecting stormwater runoff, et cetera. Never drink water from these places.

Cypress Domes

Stands of cypress trees dot the landscape of south and central Florida, until about the Ocala National Forest when hiking northbound. In the center of every cypress dome is a reliable deep pool of water.


Even in dry years, when Big Cypress is nothing but mud, cypress domes are reliable water sources. You can always  get water from a cypress dome, even if your guidebook does not list it as a water source.

Springs & Sinkholes

North Florida is famous for its large magnitude artesian springs that pump millions of gallons of cool clear water from the aquifer every day. Florida Trail hikers encounter them in the Ocala National Forest. With respect to chemical pollutants, this water is safe to drink but should still be treated. Springs are popular places to swim and so may be polluted with bacteria and protozoa from people and their dogs, as well as feces from deer, wild boar, et cetera.


Sinkholes form when underground limestone collapses. Their (usually) steep sides and circular shape make them easy to spot. These depressions can fill up with both rainwater and water from the aquifer. Unless right next to a road, water from sinkholes is safe to drink once filtered. Do not climb down a steep bank to reach a pool, however.

Small Creeks

Small creeks and streams are safe to drink from once filtered. The amounts of any potential run off are small. 


The clearest, cleanest creeks are found throughout north Florida in places like the Econfina River, Nokuse Plantation, and Eglin AFB. But while the water may appear clear, fine particles of clay quickly clog filters, so always use a pre-filter, no matter how clear the water appears.

Man-Made Wells

Occasionally there is a hand-operated well pump at official designated campsites on public lands. There is nothing like them on the AT or PCT, and some look like cast-iron pumps from the 18th and 19th centuries. A well's benefit is that it delivers relatively clean ground water, in places where there might not be a stream or spring, but even water from a well should be treated.


Operating a hand pump:

  • Some wells have to be primed before they will work. If so, there should be a bucket or plastic jug nearby filled with water. Pour that water down the opening at the top of the well head until it overflows, then push the well's handle down.
  • Before leaving, always refill the bucket/jug so the next guy can use the well.


A few caveats:

  • In some older wells the water is tinted with rust from old pipes. Dissolved rust cannot be removed with a water filter, but is safe to drink.
  • Some wells in Ocala National Forest have been destroyed by assholes. They nevertheless appear on maps produced by the Forest Service, to the consternation of section and weekend hikers. They are not  listed as water sources in the FTA databook or Friend & Keatley's guidebook, however.
  • Some well designs have seals that can fail or decay over time, sapping the well's pressure and making it non-functional. When this happens, the news is slow to make it into the databook and guidebook. You may reach a well only to discover it is not functioning — a frustrating experience.
  • We have found at least one well (Jane Green Campsite) contaminated with silt and clay. It pumps a few gallons of clean water at first, but then silt and clay appears. Be judicious about your well water use.


Always Filter! After seeing thick clouds of algae, leaf litter, and dirt floating in your water, we doubt you will want to drink it without filtering first. However, weight savings tempts people to do foolish things — like all the hikers on the AT and PCT not treating their water at all, despite the risk of giardia.


Water on the Florida Trail must  be filtered. We strongly discourage you from relying upon chemicals like iodine or Aqua Mira to treat drinking water, as well as the ultra-violet light of a SteriPEN. We are not confident that these treatments effectively kill all the parasites, amoebas, protozoa, bacteria, et cetera in Florida's water. Why? Because with very, very few exceptions, all water sources on the FT are heavily filled with particulates like algae, clay, dirt, and plant matter that can shield bugs. It is easy to imagine a parasite safely encased within a clump of clay invisible to the naked eye. "Pre-filtering" by pouring dirty water through a handkerchief (etc) is not sufficient because the gaps between fibers are enormous relative to microbial life. Water filtered through a handkerchief doesn't even appear clean to the naked eye (we've tried).


The bottom line is, weight is no longer an excuse not to filter. The Aqua Mira set weighs 3 ounces. The Sawyer mini weighs half that at just 1.4 ounces, and it's only $25! There is just no excuse.


Filter Options

In our gear section we go into detail about the different filters out there, and give our recommendations for which ones best solve the problems of the Florida Trail.

Expert Tip: Bring a Jug for Dirty Water

To reach the deep, clear water of a cypress dome, for example, you often slog through mud and muck. Since filtering takes time and there is no place to sit down, you end up standing over the water while the filter does its thing. The filter clogs often, so you spend even more time standing in the water/mud while cleaning the filter. It's never much fun, but it's especially tedious at the end of the day.


To avoid all that, we recommend carrying an empty gallon jug or a dedicated bladder for dirty water. With one of these you can walk out to the water source, fill up, and then filter back in camp while sitting down on dry land (or in a shady spot if it's in the middle of the day). It's far less stressful.

  • Taking an MSR or other pump filter?  Bring a gallon jug so you can drop the pump's source hose into the jug.
  • Taking a Sawyer mini or other in-line filter? Bring a 4-5 liter Platypus bag dedicated for dirty water. The filter screws onto the bag's opening and if you hang the bag from a branch, gravity does the work for you.

The Paradox of Water in Florida

Water surrounds Florida on three sides, and yet the state faces a politically intractable water crisis. In one sense, this is a new phenomenon caused by a massive population explosion, but in another sense it is a problem as old as Florida itself. At Florida's heart lies a paradox: there is both too much water, and not enough.

In the eyes of European settlers swamps, marshes, and even the Everglades were seen as "worthless" lands that needed to be "reclaimed" for productive use. Draining and destruction of Florida swamps and marshes continues today under the failed policy of "no net loss", even as the state faces a drinking water shortage. And when the first Europeans attempted to farm the lands that weren't swampy, they discovered that despite regular heavy rains, the sandy soil did not retain much water and wasn't much good for crops.


Florida Trail thru-hikers experience this paradox first hand. They hike through huge swamps, cross numerous streams, and skirt the edges of wetlands, and yet at the same time finding a good source of drinking water can be tough. The trail has both too much and too little water.