Human feces left on or buried in forest soil typically break down visibly within a few weeks in warm, moist conditions, but full decomposition of the organic material can take anywhere from two months to well over a year depending on temperature, soil biology, and moisture. That range is wide because “decompose” means different things: the solid mass may disappear relatively quickly, while disease-causing organisms inside it can linger in the soil for months. The gap between those two timelines matters more than most hikers realize.
What Feces Are Made Of and Why That Matters
The speed of breakdown starts with what is actually in a pile of human waste. Feces are mostly water, somewhere around 75 to 82 percent by weight, which means that in a dry, sunny environment, much of the initial mass simply evaporates rather than decomposes biologically.1Doboku Gakkai Ronbunshu. Characterization of Feces for Describing the Aerobic Biodegradation of Feces The remaining solid fraction is roughly two-thirds biodegradable organic material and one-third a mix of non-biodegradable volatile solids and inorganic matter like minerals.1Doboku Gakkai Ronbunshu. Characterization of Feces for Describing the Aerobic Biodegradation of Feces So about a fifth of what you leave behind resists biological breakdown altogether.
The organic fraction itself is dominated by bacteria. Bacterial biomass makes up roughly a quarter to more than half of the dry solids, with undigested carbohydrates, fiber, protein, and fat filling out the rest.2PubMed Central. The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology Diet has a big influence here. People eating high-fiber diets produce roughly twice the fecal mass of those on low-fiber diets, and that fiber-rich waste tends to be more attractive to the soil organisms that do the decomposing.2PubMed Central. The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology In practical terms, the more plant-heavy your diet, the bulkier and faster-decomposing your waste will be. But “faster” in this context still means weeks, not days.
Temperature, Moisture, and Soil Chemistry
The single biggest factor controlling decomposition speed in the woods is temperature. Warm soil accelerates microbial activity dramatically. A deposit left in a temperate forest during July will break down far faster than one left in October, and one left in January on frozen ground can sit essentially unchanged until spring. Research on fecal decomposition in northeastern forests found that snow and freezing conditions did not directly destroy fecal material; it simply waited until warmer weather returned to resume breaking down.3Global Change Biology. Winter climate change implications for decomposition in northeastern forests: comparisons of sugar maple litter with herbivore fecal inputs If you are camping in a cold climate or at high altitude where the soil rarely gets warm, expect decomposition to stall for months.
Moisture is the second critical variable, but the relationship is not linear. Soil needs to be damp for microbial communities to thrive, and bone-dry conditions halt biological activity almost entirely. But waterlogged soil creates anaerobic conditions that slow aerobic decomposition, the main pathway for breaking down fecal solids. The sweet spot is moist, well-drained forest floor, the kind you find in most deciduous or mixed-forest environments during the growing season.
Soil pH adds another layer. Acidic forest soils, common under conifer stands, slow decomposition across the board. Research on temperate forest soils showed that litter decomposition rates dropped in a roughly linear fashion as soil pH decreased, regardless of what was being decomposed or how many nutrients were available.4Functional Ecology. Forest soil acidification consistently reduces litter decomposition irrespective of nutrient availability and litter type If you bury waste under a stand of spruce or hemlock where the duff is thick and acidic, expect a slower timeline than under a stand of hardwoods with near-neutral soil. This is worth knowing when you are choosing where to dig a cathole.
Insects and Soil Organisms Do Most of the Work
Microbial decomposition handles the chemical breakdown, but in many forest ecosystems the physical removal and redistribution of fecal material is driven by insects, especially dung beetles. These beetles locate feces on the surface, carve out portions, and bury them in underground tunnels where the material feeds their larvae. In the process, they mix fecal nutrients directly into the soil far faster than passive leaching would achieve.
Research in forest ecosystems has found that dung beetles remove the majority of surface fecal material, eliminating breeding habitat for pest flies while cycling nutrients belowground.5Journal of Insect Behavior. Parasites and Dung Beetles as Ecosystem Engineers in a Forest Ecosystem Larger-bodied beetle species have an outsized impact. In one study of Afrotropical forest, large dung beetles enriched surrounding soil by an average of about 45 percent across all measured nutrients compared to soil where feces sat without any beetle activity.6PubMed Central. The Effect of Dung Beetle Size on Soil Nutrient Mobilization in an Afrotropical Forest In temperate North American and European forests, the beetle community is less diverse but still plays a meaningful role.
Here is the catch: dung beetles evolved primarily to find the waste of wild herbivores and omnivores, not humans. Human feces in the woods may still attract beetles and other coprophagous insects, but the response is less predictable than it would be for a deer or elk scat pile. A pile deposited on rock, snow, or in a very dry environment may get almost no insect attention, leaving decomposition entirely to microbes and weather. Burying waste in a cathole partially mimics what beetles do naturally, putting the material in contact with soil organisms that can break it down.
When the Pile Disappears But the Pathogens Don’t
This is where the question gets more consequential. Visible decomposition and pathogen die-off happen on very different schedules. You might revisit a spot a month later and see nothing, but the soil beneath may still harbor infectious organisms. Two of the most commonly studied waterborne parasites found in human feces are Giardia and Cryptosporidium, and their survival in soil is surprisingly resilient under certain conditions.
Giardia cysts are the more fragile of the two. In soil at cool temperatures, around 4°C, they remained infectious for about seven weeks. At warm temperatures near 25°C, infectivity dropped within two weeks. A single week of freezing to −4°C rendered them noninfective.7Journal of Environmental Quality. Giardia Cyst and Cryptosporidium Oocyst Survival in Water, Soil, and Cattle Feces If you camp in a place that freezes hard through winter, Giardia from the previous season is unlikely to persist until the following year.8PubMed. Effects of the Norwegian winter environment on Giardia cysts and Cryptosporidium oocysts
Cryptosporidium is tougher. Its oocysts survived more than 12 weeks in water and soil at both freezing and cool temperatures. Warm conditions sped up their degradation, but not as dramatically as with Giardia.7Journal of Environmental Quality. Giardia Cyst and Cryptosporidium Oocyst Survival in Water, Soil, and Cattle Feces Soil type matters too. Sandy, porous soils dried out oocysts faster and led to quicker inactivation, while clay-heavy soils with more organic matter shielded the parasites from desiccation and UV exposure.9PubMed Central. Environmental Factors Associated with Cryptosporidium and Giardia
E. coli, the classic indicator of fecal contamination, has its own persistence timeline. In some soil types, especially poorly drained ones, E. coli has been detected in soil water months after the original contamination event.10PubMed Central. Long-term persistence and leaching of Escherichia coli in temperate maritime soils Rainfall is a major transport mechanism. Even moderate rain can carry bacteria from a surface deposit or a shallow burial site downward through the soil profile and potentially toward groundwater, streams, or lakes.11PubMed Central. Leaching of Escherichia coli O157:H7 in diverse soils under various agricultural management practices Cryptosporidium oocysts were detected in leachate from intact soil cores for months after surface application, with preferential flow through cracks and macropores in the soil acting as express lanes for pathogen transport.12PubMed Central. Leaching of Cryptosporidium parvum oocysts, Escherichia coli, and a Salmonella enterica serovar Typhimurium bacteriophage through intact soil cores following surface application and injection of slurry
The practical takeaway: even when feces are invisible, the ground where they were deposited can remain a source of contamination for weeks to months. This is why catholes should be dug at least 200 feet from any water source, not because the feces will wash directly into the creek, but because rain percolating through that soil can carry pathogens along with it.
What About Toilet Paper and Wipes
Most people who go in the woods use something to clean up with, and whatever they use has its own decomposition timeline. Plain, unbleached toilet paper breaks down relatively fast in moist soil, often becoming unrecognizable within a few weeks. Research on paper product breakdown in natural environments found that depth of burial did not significantly affect the rate of decay for toilet paper, though moisture and microbial activity in the surrounding soil did.13PubMed. An analysis of the breakdown of paper products (toilet paper, tissues and tampons) in natural environments, Tasmania, Australia That said, in dry or cold conditions, used toilet paper can persist far longer than the feces itself, becoming the most visible trace of human waste in the backcountry.
Wet wipes are a different story entirely, and their growing popularity among hikers and campers has created a genuine problem. Standard wet wipes contain synthetic fibers, typically polyester, that resist biological breakdown in soil. In beach sand experiments, wipes containing plastic remained largely intact for the full 15-week study period, while compostable versions fragmented and degraded within that time.14PubMed. Persistence of ‘wet wipes’ in beach sand: An unrecognised reservoir for localised E. coli contamination The polyester content is the key variable: higher synthetic fiber content means slower degradation, and most conventional wet wipes are majority synthetic.15TEXTEH Proceedings. DEGRADATION OF NONWOVEN FABRICS SUITABLE FOR WET WIPES BURIED IN SOIL Even “flushable” or “biodegradable” wipes break down far more slowly in forest soil than in the industrial composting conditions they were tested under. If you use wipes in the backcountry, pack them out. Burying them is not a solution.
Why Catholes Work and When They Don’t
The standard backcountry recommendation, dig a hole six to eight inches deep, at least 200 feet from water, trails, and campsites, exists because it places feces in the biologically active layer of the soil where decomposition is fastest. At that depth, you get contact with the richest community of soil microbes, a buffer of soil to filter pathogens before they reach deeper groundwater, and enough cover to prevent surface flies from accessing the waste. The system works reasonably well in most temperate and tropical forests where the soil is deep, organic, and warm enough for microbial activity.
Catholes are less effective in several common backcountry settings:
- Alpine environments: Above treeline, soil is thin, cold, and sparsely populated by decomposer organisms. Feces buried in alpine tundra can persist for a year or longer with minimal breakdown. Many popular high-altitude areas now require pack-out systems for this reason.
- Desert and arid lands: With little moisture and sparse microbial life, decomposition stalls. In some desert environments, surface smearing (spreading waste thinly on sun-exposed rock to maximize UV sterilization) has been recommended as an alternative, though the practice remains debated.
- Snow-covered terrain: Waste deposited on snow stays frozen, then gets deposited wherever the snow melts, often in drainage channels and near water. Winter camping in snow requires either very deep catholes dug to mineral soil or pack-out.
- High-traffic areas: Even in otherwise ideal decomposition conditions, if enough people use the same small area, the soil’s microbial community gets overwhelmed. The cumulative pathogen load can exceed what the soil can neutralize, particularly near popular campsites along heavily used trails.
The rise of pack-out waste bag systems reflects these limitations. Research at a popular park found that nearly a third of visitors who defecated during their trip used pack-out bags, and the vast majority of those who used them relied on free bags provided at trailheads, suggesting that willingness is not the barrier so much as availability.16Electronic Theses and Dissertations for Graduate School. Exploring the Psychosocial and Behavioral Dimensions of Park Visitors’ Human Waste Management Practices If the option is there and it is free, people will use it.
How Medications and Chemicals Affect the Process
Something that rarely comes up in backcountry ethics discussions but matters for the decomposition question: what you have consumed changes what your feces do in the soil. Pharmaceutical residues, especially antibiotics, pass through the human body partially intact and end up in waste. Once in the soil, antibiotics can suppress the very microbial communities needed for decomposition. Research on pharmaceutical compounds in soil has documented that antibiotic residues cause measurable shifts in soil microbial communities, with effects that depend on dose and how long the compounds persist.17Journal of Plant Nutrition and Soil Science. Pharmaceutical antibiotic compounds in soils – a review
This does not mean that a single hiker on a course of amoxicillin is going to sterilize a patch of forest. But it does mean that in high-use areas where many visitors are depositing waste, the cumulative load of pharmaceuticals, hormones, and other bioactive compounds could slow microbial turnover in the soil. It is another argument for pack-out systems in popular areas, and a reminder that the “bury it and forget it” approach works best when visitor density is low.
The Difference Between Decomposition and Safety
If you are asking how long it takes for poop to disappear from the forest floor, the answer in favorable conditions is a matter of weeks. Warm, moist, slightly acidic to neutral soil with active insect and microbial communities will render a buried deposit visually undetectable within a month or two. In cold, dry, or acidic conditions, or at high elevation, it can take six months to more than a year.
But if you are asking how long until that spot is safe, the answer is longer. Giardia and Cryptosporidium can remain infectious in soil for weeks to months after the fecal mass itself has been broken down by microbes and insects. E. coli and other bacteria can leach through the soil profile with rainfall for months. The 200-foot rule for distance from water is not arbitrary caution; it reflects the reality that pathogen transport through soil is a slow but persistent process, particularly in clay-rich or poorly drained soils. If you are choosing between a cathole and a pack-out bag in a sensitive area, the bag is almost always the better choice for the ecosystem, even if the cathole “works” in the narrow sense of hiding your waste from view.