5 Best Waterless Composting Toilets for Off Grid Farms
Discover the 5 best waterless composting toilets for off-grid farms. Compare capacity, maintenance, and cost to find the right system for your barn or outbuilding.
Finding the right waterless composting toilet for your off-grid farm isn’t about choosing the most expensive option, it’s about matching the system to your specific setup, usage patterns, and maintenance capabilities. This guide is based on extensive curation and deep research into proven models that hobby farmers actually use in barn offices, workshops, and remote outbuildings. These five systems represent different approaches to waterless sanitation, each with distinct advantages depending on your farm’s layout and needs.
Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!
1. Nature’s Head Self-Contained Composting Toilet
Key Features and Design
Nature’s Head uses a hand-crank agitator to mix composting material, eliminating the need for electricity in the composting process itself. The urine-diverting design separates liquids into a front bottle while solids collect in the main chamber with coconut coir or peat moss.
The spider handle crank operates smoothly even when the chamber’s nearly full. A small 12-volt fan (drawing about 1.5 watts) vents odors through a standard hose, which you can run through a wall or roof.
The entire unit sits low to the ground at standard toilet height. Installation takes maybe an hour if you’re handy with basic tools, mount the vent hose, connect the fan to your 12V system, and you’re operational.
Why It Works for Hobby Farms
Most hobby farmers put Nature’s Head in workshops, barn offices, or seasonal cabins where daily use stays moderate. Two people using it full-time will empty the solids chamber every 4-6 weeks, while weekend-only use stretches that to several months.
The urine bottle requires more frequent attention, typically every 3-5 days with regular use. That’s actually an advantage on farms since diluted urine makes excellent liquid fertilizer for nitrogen-hungry crops like tomatoes or corn.
The compact footprint (21″ deep x 18″ wide) fits in tight spaces. You’re not dedicating precious square footage to bathroom facilities in structures where every foot counts.
Pricing and Maintenance
Expect to pay around $1,000-$1,100 for the complete unit. That upfront cost includes everything except the composting medium, you’ll need coconut coir bricks or peat moss, which run maybe $15-20 per chamber cycle.
Maintenance involves three simple tasks: empty the urine bottle regularly, turn the crank after solid waste deposits, and add composting medium as needed. The fan might need replacement after several years of continuous operation, but that’s a $30 part.
The finish composting happens outside the unit. When you empty the chamber, the material still needs 6-12 months of outdoor composting before use around ornamental plants (never use humanure on food crops without extended hot composting verification).
2. Sun-Mar Excel Non-Electric Composting Toilet
Large Capacity for Farm Use
Sun-Mar Excel handles higher traffic than most self-contained units, up to 3 adults in residential use translates to reliable performance for 4-6 people in intermittent farm settings. The drum-style composting chamber holds considerably more material before requiring emptying.
The hand-crank drum tumbler mixes waste with bulking material efficiently. Unlike vertical designs where material can compact at the bottom, the rotating drum ensures consistent aeration throughout the composting mass.
This unit produces actual compost rather than requiring external finishing. The two-chamber system lets one side finish composting while the other receives fresh material, genuine continuous operation if managed properly.
Ventilation System Advantages
The passive ventilation stack extends through your roof, creating natural draft as warm air rises. No fan, no power consumption, no electrical components to fail, pure thermodynamics doing the work.
That stack needs to extend at least 18 inches above your roofline and should reach higher if your building sits in a depression or near taller structures. Inadequate stack height creates pressure problems that cause odors to escape into the room.
Draft performance varies with temperature differentials. Cold weather creates stronger updraft, while hot summer days with minimal temperature difference can reduce ventilation effectiveness. Most hobby farmers report zero odor issues in proper installations, but summer performance depends on stack height and positioning.
Installation Considerations
The Excel requires more permanent installation than portable units. You’re cutting a 4-inch hole through your roof, installing the vent stack, and positioning the 44-pound unit where it’ll stay.
Footprint measures 22″ x 33″ x 28″ high, notably larger than compact alternatives. That size matters in small outbuildings but offers the benefit of extended capacity between servicing.
Floor structure needs to support concentrated weight. Most barn offices and workshops handle this fine, but older structures with questionable flooring might need reinforcement. Budget roughly $950-$1,050 for the unit itself, plus another $100-150 for proper vent stack installation materials.
3. Separett Villa 9215 AC/DC
Urine-Diverting Technology Explained
Separett takes a different approach, complete separation of liquids and solids from the start. The front bowl section channels urine through a drain connection while solids drop into a compostable bag-lined container below.
This isn’t technically composting in the unit. You’re collecting waste for external composting, which some hobby farmers prefer because it removes the decomposition process from the building entirely.
The fan runs continuously to ventilate the solids container, preventing odor and beginning the drying process. That constant air movement keeps things remarkably smell-free if your vent installation follows proper guidelines.
Power Flexibility for Off Grid Living
The AC/DC model switches between 110V household current and 12V DC power, genuine flexibility for mixed power situations. Maybe your barn has solar with battery backup, or you run a generator periodically and want the toilet functional regardless of power source.
Fan power draw stays minimal on either voltage. On 12V DC operation, you’re pulling roughly 4-5 watts continuously, manageable even on modest solar setups with limited battery capacity.
Some hobby farmers wire it to a small dedicated solar panel and battery, creating an independent toilet power system. That approach works particularly well for remote outbuildings where running power lines costs more than a standalone solution.
Best Use Cases on Hobby Farms
Separett excels in situations where you want simple waste removal rather than on-site composting. Farm stands with customer restrooms, remote equipment sheds used sporadically, or seasonal housing benefit from the bag-and-remove approach.
You’ll empty the solids container when the bag fills, frequency depends entirely on usage patterns. Weekend-only use by 1-2 people might mean monthly removal, while daily use requires weekly attention.
Liquid drainage requires either a connection to a greywater system, a collection container, or approved dispersal into soil. That urine line can’t freeze, which creates winterization challenges in unheated buildings in cold climates. Expect to invest around $1,000-$1,100, with ongoing costs limited to compostable bags (roughly $0.75-$1.00 per bag).
4. Laveo Dry Flush Portable Toilet
How the Bagging System Works
Laveo operates more like a specialized waste container than a composting system. Each use triggers a battery-powered mechanism that wraps waste in a multi-layer barrier film, sealing it hermetically before returning to ready position.
The cartridge holds roughly 15-17 uses before requiring replacement. When full, you remove the sealed waste tube and dispose of it, typically in regular trash where regulations allow, though rural hobby farmers often incorporate sealed waste into outdoor long-term composting piles.
No venting, no plumbing, no permanent installation required. The entire unit weighs about 30 pounds and moves wherever needed. Four D-cell batteries power the bagging mechanism for approximately 1,000 flushes.
Portability Benefits for Farm Outbuildings
This portability shines in temporary or rotating situations. Field harvest operations, seasonal pasture shelters, or equipment you move between locations all benefit from a toilet that relocates easily.
You’re not limited to buildings with wall or roof penetration capabilities. A chicken processing setup you use twice yearly, a lambing shed occupied only in spring, or a sugarhouse active during maple season, none need permanent toilet installation.
Weather resistance allows outdoor use in covered locations. Some hobby farmers keep one in a weatherproof enclosure near garden plots or remote pastures, avoiding the walk back to the main house during intensive work periods.
Operating Costs and Cartridge Replacements
The economics shift dramatically compared to true composting systems. Replacement cartridges run approximately $10-$12 each, supporting 15-17 uses. That calculates to roughly $0.65-$0.80 per use.
For occasional use, that’s manageable. Weekend farm visits totaling maybe 12 uses monthly costs around $9. Full-time daily use by one person approaches $20-25 weekly, unsustainable long-term compared to actual composting toilets.
The unit itself costs around $500-$600, making initial investment significantly lower than composting alternatives. That lower entry cost appeals to hobby farmers testing whether a remote toilet improves their farm workflow before committing to permanent installation.
But you’re essentially renting convenience through ongoing cartridge purchases. Calculate your expected annual uses and compare that operating cost against higher-priced composting units with minimal ongoing expenses.
5. Biolet 65 Non-Electric Composting Toilet
The OGO™ Compost Toilet eliminates odors and the need for dump stations with its urine-separating design. Built in the USA, it features a removable waste bin and a 2.4-gallon urine bottle for easy cleaning.
Continuous Composting Chamber Design
Biolet 65 features a large single chamber where material continuously breaks down from fresh at the top to finished compost at the bottom. The thermophilic composting process generates heat naturally through microbial activity, accelerating decomposition.
A manual mixing rake aerates the pile periodically. This isn’t a rotating drum, you’re pulling the rake through the chamber to distribute material and maintain oxygen levels throughout the composting mass.
The non-electric version relies entirely on passive stack ventilation, similar to Sun-Mar’s approach. That 4-inch vent stack extending through your roof creates the natural draft necessary for odor control and moisture evaporation.
Durability for Heavy Farm Use
This unit’s built for punishment. The molded high-density polyethylene construction handles temperature extremes, impacts, and the general abuse farm equipment endures.
Capacity rating suggests 4-6 people in residential use. For hobby farms, that translates to reliable service in communal spaces like shared farm facilities, agritourism venues with moderate traffic, or main barn restrooms serving multiple family members working simultaneously.
The chamber volume reduces emptying frequency significantly, potentially 6-12 months between removals with moderate use. That interval matters when your toilet occupies a workshop or barn where disrupting operations to service equipment creates scheduling headaches.
Compost Output and Agricultural Benefits
Finished material exits from the bottom drawer as actual compost, dark, crumbly, reduced in volume by 90% from original input. This differs fundamentally from units requiring external finishing.
The thermophilic process achieves temperatures that reduce pathogens more effectively than cold composting. While you still shouldn’t use humanure on food crops without extended verification composting, the output serves perfectly around fruit trees, ornamental landscaping, or soil-building operations for future garden plots.
Some hobby farmers empty their Biolet directly into dedicated humanure finishing bins, where material completes a final year of aging before cautious agricultural use. Others apply it immediately to non-food ornamentals or use it to reclaim eroded areas, suppress weeds along fence lines, or improve soil in future pasture conversions.
Expect to invest around $1,400-$1,600 for the unit. Operating costs remain minimal, just occasional peat moss or coconut coir additions to maintain proper carbon balance. That higher upfront cost buys genuine capacity and reduced maintenance frequency, which pays dividends when farm operations keep you too busy for frequent toilet servicing.
Frequently Asked Questions
What is the best waterless composting toilet for off-grid farms?
The best waterless composting toilet depends on your specific needs. Nature’s Head works well for workshops with moderate use, while Biolet 65 handles heavier traffic. Sun-Mar Excel offers true continuous composting, and Separett Villa provides flexible power options for varied off-grid setups.
How often do you need to empty a composting toilet on a farm?
Emptying frequency varies by model and usage. Nature’s Head requires emptying every 4-6 weeks with two full-time users, while larger units like Biolet 65 can go 6-12 months. The urine container typically needs emptying every 3-5 days with regular use.
Do waterless composting toilets smell bad in farm buildings?
Properly installed waterless composting toilets produce no noticeable odor. Ventilation systems—whether 12V fans or passive stack vents—continuously remove odors. Adequate vent stack height and proper composting medium maintenance are essential for odor-free operation in workshops and barns.
Can you use humanure from composting toilets on vegetable gardens?
Humanure should never be used directly on food crops without extended hot composting verification. Most composting toilet output requires 6-12 months of additional outdoor composting. It’s safe for ornamental plants, fruit trees, and soil reclamation projects immediately after removal.
How much does it cost to install a composting toilet in a barn?
Initial costs range from $500-$1,600 depending on the model. Nature’s Head costs around $1,000-$1,100, while Biolet 65 runs $1,400-$1,600. Installation materials like vent stacks add $100-$150. Ongoing costs include composting medium at $15-20 per cycle or replacement cartridges for bag systems.
What power source do off-grid composting toilets need?
Most waterless composting toilets require minimal power. Units like Nature’s Head use 12V fans drawing just 1.5 watts, perfect for solar systems. Separett Villa offers AC/DC flexibility, while models like Sun-Mar Excel and Biolet 65 non-electric versions operate completely without power using passive ventilation.
