Can You Compost Human Feces? The Complete Guide to Humanure Safety and Alternatives

Why Gardeners Are Asking About Composting Human Waste

As sustainable gardening practices gain momentum, more gardeners are exploring ways to create truly closed-loop systems in their gardens. The concept is appealing: what if we could recycle all organic matter, including our own waste, back into the garden? This "waste-to-resource" thinking represents the ultimate form of sustainability—turning what's typically flushed away into valuable nutrients for growing food.

Human waste, often called "humanure" in composting circles, contains many of the same nutrients plants need to thrive. Nitrogen, phosphorus, and potassium—the primary components in commercial fertilizers—are abundant in human excrement. For gardeners committed to reducing their environmental footprint, the idea of capturing these nutrients rather than flushing them away seems logical.

However, this topic raises legitimate health and environmental concerns. Unlike kitchen scraps or yard waste, human waste carries specific pathogens that can cause serious illness when improperly managed. Additionally, laws and regulations around humanure vary widely, creating confusion about what's actually permitted.

In this comprehensive guide, you'll learn the real risks of humanure, when (if ever) it can be safely used, practical alternatives that achieve similar sustainability goals, and step-by-step instructions for implementing safer options in your garden this season.

Quick Reference Guide: Humanure Facts

Material Properties:

Carbon-to-Nitrogen Ratio: 5-10:1 (extremely nitrogen-rich)
Nutrient Content: High in nitrogen, phosphorus, potassium, and micronutrients
Pathogen Risk: Very high (contains E. coli, potential parasites, viruses)
Processing Requirements: Thermophilic composting at 145°F+ for minimum 3 consecutive days, followed by 1-2 years aging
Legal Status: Prohibited in most residential areas; regulated under waste management laws

Benefits When Properly Processed:

Creates closed nutrient loop
Reduces water usage from conventional toilets
Prevents nutrients from entering and potentially contaminating waterways
Builds soil organic matter when safely composted

Primary Concerns:

Pathogen transmission risk
Legal restrictions in most areas
Requires specialized management systems
Potential for soil contamination if improperly processed

5 Critical Health Risks of Humanure You Must Understand

Unlike animal manures commonly used in gardens, human waste presents unique and serious health hazards that every gardener should understand before considering its use.

1. Persistent Pathogens
Human feces can contain numerous disease-causing organisms that ordinary composting doesn't reliably kill. These include pathogenic strains of E. coli, Salmonella, Shigella, and Campylobacter bacteria. Additionally, parasites like Giardia, Cryptosporidium, and various helminth (worm) eggs can survive for extended periods in soil. Viruses, including hepatitis A and norovirus, may also be present and can remain viable in improperly processed waste.

2. Different from Animal Manures
While chicken, cow, and horse manures are widely accepted in gardening, human waste is fundamentally different. The pathogens in human waste are specifically adapted to infect humans, creating a direct transmission pathway when used on food crops. Animal manures primarily contain species-specific pathogens that pose less risk to humans. Furthermore, herbivore manure (like cow and horse) has already passed through complex digestive systems that break down many pathogens, unlike human waste.

3. Long-Term Soil Contamination
If contaminated with pathogens, garden soil can remain unsafe for 1-2 years or longer. Some parasitic eggs can survive in soil for up to 10 years under favorable conditions. This persistent contamination means that even after removing visible traces of humanure, your garden could remain a source of infection for seasons to come.

4. Documented Illness Cases
There are numerous documented cases of illness resulting from improper handling of human waste in agricultural settings. In 2006, a widespread E. coli outbreak linked to contaminated spinach sickened over 200 people and caused three deaths. While this particular case involved animal waste contamination, it demonstrates how easily pathogens from fecal matter can spread through food crops. Similar pathways exist with improperly managed humanure.

5. Inadequate Home Composting Temperatures
Standard backyard compost bins typically reach only 110-120°F at their hottest points. This falls significantly short of the 145°F sustained temperature needed to kill pathogens in human waste. Even well-managed backyard systems experience temperature fluctuations and cold spots that allow pathogens to survive. Without specialized equipment to monitor internal temperatures, home composters cannot verify that pathogen-killing conditions have been achieved throughout the pile.

Is Composting Human Waste Legal? Know Your Local Laws

Before considering any humanure composting, it's essential to understand the legal landscape, which varies significantly depending on where you live.

Urban and Suburban Regulations
In most urban and suburban areas across the United States, composting human waste is explicitly prohibited by local health codes. Cities like Portland, Seattle, and Austin—despite their progressive stances on composting—maintain strict regulations against humanure in residential settings. These restrictions exist primarily to prevent disease transmission in densely populated areas where improper management could affect neighbors.

Rural Considerations
Rural areas sometimes have more flexible regulations, but still typically require permits or approved systems for managing human waste outside of conventional septic or sewer systems. Even on private rural property, improper waste management can violate state environmental protection laws if there's potential for groundwater contamination or watershed impacts.

Why the Prohibitions Exist
Local health departments prohibit residential humanure composting because modern waste treatment systems provide crucial public health protections. Municipal wastewater treatment facilities use controlled processes including filtration, chemical treatment, and monitoring to ensure pathogens are neutralized before water is released back into the environment. These systems represent significant public health achievements that have dramatically reduced waterborne disease outbreaks.

Consequences of Violations
Violating local waste management ordinances can result in significant fines, typically ranging from $500 to several thousand dollars for first offenses. Beyond financial penalties, improper waste management can lead to environmental damage, including groundwater contamination that affects neighboring properties and natural waterways. This contamination is particularly concerning near wells or water sources.

When Exceptions Apply
Some jurisdictions do permit approved composting toilet systems that meet specific certification standards (NSF/ANSI Standard 41 is common). These systems typically require professional installation, ongoing maintenance, and sometimes periodic inspection. Agricultural permits for experimental systems exist in some states, but these generally apply to research institutions rather than home gardeners. Always check with your local health department or county extension office for current regulations in your specific area.

When Can Humanure Actually Work Safely?

Despite the significant risks and legal considerations, there are circumstances where human waste can be safely composted—though these require strict adherence to scientific protocols far beyond casual backyard composting.

The Science of Thermophilic Composting
Safe humanure composting relies on thermophilic (heat-loving) bacteria that thrive at high temperatures. To effectively kill pathogens, compost must maintain temperatures of at least 145°F (63°C) for a minimum of three consecutive days throughout the entire pile. Achieving these temperatures requires careful management of carbon-to-nitrogen ratios, moisture content (40-60%), sufficient pile size (at least one cubic yard), and regular turning to ensure all material reaches pathogen-killing temperatures.

Time Requirements for Safety
Even after achieving proper thermophilic conditions, humanure compost requires extended aging—typically 1-2 years—before it can be considered safe for food gardens. This extended aging period allows for the die-off of more resistant pathogens and the completion of decomposition processes. This timeline is substantially longer than the 3-6 months typically recommended for standard yard waste compost.

Essential Management Protocols
Certified humanure systems follow strict protocols, including:

Designated composting areas separated from food production
Impermeable barriers beneath compost piles to prevent leaching
Cover materials (at least 12 inches of carbon-rich material) to prevent odors and flies
Dedicated tools that never mix with regular garden equipment
Handwashing stations and personal protective equipment
Temperature monitoring with long-stem thermometers
Detailed record-keeping of temperature readings and pile management

Testing Before Use
Before application to food gardens, properly processed humanure should be laboratory tested for indicator organisms like fecal coliform bacteria. Commercial labs can provide this service for around $50-100 per sample. The absence of these indicator organisms suggests that more dangerous pathogens have also been eliminated. Without testing, there's no way to verify safety.

Case Study: Off-Grid Communities
The Dancing Rabbit Ecovillage in Missouri uses a managed humanure system that follows a strict protocol: collection in sawdust toilets, composting in dedicated bins away from food production areas, and aging for two full years before limited use on non-food crops and fruit trees (never root vegetables or low-growing foods). Their system includes detailed record-keeping, training for all community members, and regular testing. This level of management requires significant community commitment and education.

Emergency Situations
In disaster scenarios where conventional systems are unavailable, temporary humanure management may become necessary. Organizations like SOIL in Haiti have developed emergency composting toilet systems that use similar thermophilic principles. However, these are designed as temporary solutions until proper infrastructure can be restored, not as preferred long-term approaches.

6 Safer Alternatives to Humanure for Home Gardens

Fortunately, several safer alternatives can help you achieve similar sustainability goals without the health risks or legal concerns of humanure composting.

1. Urine Fertilizing
Human urine is typically sterile when fresh and contains approximately 80% of the nutrients humans excrete, particularly nitrogen, phosphorus, and potassium. Unlike feces, urine presents minimal pathogen risk while providing significant plant nutrition. We'll cover specific application methods in the next section, but this represents the simplest way to recapture human nutrients safely.

2. Modern Composting Toilets
Commercial composting toilets ($1,200-3,500) provide a legal, safe alternative to DIY humanure systems. These self-contained units separate liquids from solids and use controlled ventilation to promote decomposition and evaporation. Models like Nature's Head and Sun-Mar create relatively dry, odorless compost that still requires proper disposal according to local regulations—typically not directly in food gardens. Most jurisdictions require permits for installation, and the resulting material usually must be buried away from food production or disposed of through approved channels.

3. Bokashi Fermentation
This anaerobic fermentation process uses beneficial microorganisms to break down organic matter, including meat and dairy waste that traditional composting can't handle. While not designed specifically for human waste, bokashi systems are compact enough for apartment dwellers and create nutrient-rich pre-compost that can be buried in fallow garden areas to complete decomposition. A complete bokashi system costs $50-100 and can process kitchen waste in as little as two weeks.

4. Municipal Biosolid Programs
Many municipalities process sewage into biosolids (treated sewage sludge) that meet EPA standards for agricultural use. Class A biosolids have been treated to reduce pathogens to undetectable levels and are available to the public in some areas as compost or soil amendments. Contact your local wastewater treatment facility to inquire about biosolid compost availability—some offer it free to residents, while others sell it for $20-30 per cubic yard.

5. Cover Cropping
Cover crops like clover, vetch, and buckwheat build soil fertility without any manure inputs by fixing nitrogen from the air (legumes) or mining nutrients from deep soil layers (grasses and buckwheat). These crops can be cut and left as mulch or turned into the soil before planting food crops. Seeds cost $3-10 per pound, with one pound typically covering 100-200 square feet, making this an affordable fertility strategy.

6. Commercial Organic Fertilizers
Numerous commercial products derive nutrients from plant waste, food processing byproducts, and animal products (excluding manure). Options include alfalfa meal, soybean meal, cottonseed meal, and various plant-based composts. These products cost $10-30 per bag but provide safe, consistent nutrition without pathogen concerns. Look for OMRI (Organic Materials Review Institute) certification to ensure products meet organic standards.

How to Use Urine as Garden Fertilizer: Step-by-Step Guide

Of all the alternatives, urine fertilizing offers the simplest way to recapture human nutrients safely. Here's how to implement this practice effectively:

Collection Methods
Collect urine in clean, dedicated containers with tight-fitting lids—repurposed plastic jugs work well. For convenience and dignity, consider using a separate collection container in the bathroom that can be emptied into larger storage containers. For men, direct collection is straightforward; women may find a dedicated funnel helpful. Always label containers clearly to prevent confusion, and store away from food preparation areas.

Aging Requirements
While fresh urine is generally sterile, aging it for 30 days increases safety by eliminating any potential pathogens that might be present due to urinary tract infections or cross-contamination. Store in sealed containers away from direct sunlight. This aging process also converts some of the urea to more readily available forms of nitrogen through natural bacterial action.

Proper Dilution Ratios
Dilute aged urine before application to prevent burning plants:

For established plants: 10 parts water to 1 part urine
For seedlings and young plants: 20 parts water to 1 part urine
For container plants: 15 parts water to 1 part urine

Seasonal Application Timing
Apply urine fertilizer during active growing seasons, particularly in spring and early summer when plants have the highest nitrogen demands. Avoid application during dormant periods or when plants are stressed by heat or drought. For annual vegetables, stop applications a month before harvest to reduce any potential taste effects.

Plants That Thrive with Urine Fertilizer
Heavy feeders benefit most from urine fertilization:

Corn and other grains
Leafy greens like kale, spinach, and lettuce
Tomatoes, peppers, and eggplants
Squash and cucumbers
Fruit trees (apply away from trunk)

Plants to Avoid Fertilizing
Some plants perform poorly with high-nitrogen fertilizers like urine:

Root vegetables (excessive top growth at expense of roots)
Legumes (beans, peas) which fix their own nitrogen
Herbs (may affect flavor or essential oil content)
Plants in bloom (may reduce flowering)

Apply the diluted solution directly to soil around plants, avoiding direct contact with leaves or stems. One person's urine can provide sufficient nitrogen for approximately 300-400 square feet of garden space.

"I Thought All Compost Kills Pathogens" – Debunking Common Myths

Several misconceptions about composting and waste management can lead gardeners to underestimate the risks of humanure.

Myth: Backyard Composting Reaches Pathogen-Killing Temperatures
Reality: Most home compost systems simply don't get hot enough. While properly managed thermophilic compost can reach 140-160°F, most backyard bins only achieve 110-120°F at their core, with much lower temperatures throughout most of the pile. Without turning, insulation, proper moisture, and sufficient volume (at least one cubic yard), reaching and maintaining pathogen-killing temperatures is nearly impossible for home composters.

Myth: Commercial Composting Toilets Make Humanure Safe for Gardens
Reality: Most commercial composting toilets are designed to reduce volume and begin decomposition—not to completely eliminate pathogens. These systems primarily evaporate moisture and initiate breakdown through drying and aeration. The end product still requires proper disposal according to manufacturer guidelines and local regulations, typically not directly in food gardens. These systems focus on waste reduction rather than creating garden-ready compost.

Myth: Humanure Is the Same as Biosolids
Reality: Professionally processed biosolids undergo rigorous treatment processes including anaerobic digestion, heat treatment, chemical stabilization, and extensive testing before being approved for agricultural use. Class A biosolids must meet strict EPA standards for pathogen reduction and heavy metal content. Home-processed humanure lacks these controls and verification steps, making it fundamentally different from regulated biosolids.

Myth: If Pet Waste Isn't Allowed in Compost, It's Just an Arbitrary Rule
Reality: The restrictions on pet waste in compost systems stem from the same health concerns as human waste. Cats and dogs are carnivores/omnivores whose waste can contain pathogens transmissible to humans, including parasites like Toxoplasma gondii (from cats) and various roundworms. These restrictions are based on scientific understanding of disease transmission pathways, not arbitrary distinctions.

Myth: Soil Quickly Neutralizes Pathogens
Reality: Many pathogens can persist in soil environments for extended periods—from months to years depending on conditions. Some parasitic eggs can remain viable for up to 10 years in cool, moist soil. While soil biology does eventually break down pathogens, this process is much slower than many gardeners realize, especially in cooler climates or during winter months when biological activity slows.

Making Sustainable Choices That Balance Safety and Ecology

Creating truly sustainable garden systems requires balancing idealism with practical safety considerations. Start by focusing on the numerous ways to close nutrient loops without compromising health: capturing urine nutrients, composting all plant-based kitchen and garden waste, utilizing municipal compost programs, and implementing cover cropping systems.

If you're committed to more advanced waste management, consult with professionals about permitted composting toilet systems appropriate for your location. Local permaculture designers, ecological engineers, or county extension offices can provide guidance on systems that meet both sustainability goals and health regulations.

Remember that sustainability exists on a spectrum—you don't need to implement every possible practice to make a significant positive impact. Choose approaches that align with your comfort level, physical capabilities, and local regulations. Small, consistent actions often prove more sustainable than ambitious systems that become overwhelming to maintain.

Resources for Responsible Waste Management

For those wanting to explore this topic further, several resources provide valuable information:

Books and Publications

"The Humanure Handbook" by Joseph Jenkins (read critically, as some recommendations may not align with current health guidelines)
"Liquid Gold: The Lore and Logic of Using Urine to Grow Plants" by Carol Steinfeld
"The Composting Toilet System Book" by David Del Porto and Carol Steinfeld

Regulatory Information

EPA's biosolids guidelines: epa.gov/biosolids
Your local county health department website (search for "alternative waste management" or "composting toilets")

Equipment and Technology

composting-toilets.com (reviews and comparisons of commercial systems)
Sustainable Sanitation Alliance (susana.org) for research on ecological sanitation

Research Organizations

Rich Earth Institute (studies on urine diversion and fertilization)
Center for Clean Water Technology at Stony Brook University
Gardens Alive and other organic gardening suppliers for alternative fertility products

By making informed choices based on science rather than ideology, you can create a garden system that honors both ecological principles and human health—truly the essence of sustainability.