Best Composting Toilet (2026): Cabin, Tiny Home, RV

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Choose by the waste route first: compare Nature’s Head Structure Kit for a cabin with vent/power and regular bottle emptying; Separett Villa for an approved gravity urine drain; OGO Origin for a tight space with power and overhead access; TROBOLO WandaGO for short trips without power. None removes the need to handle collected waste. Check approval for your dwelling before buying.

Cabin option with a urine bottle: Nature’s Head Structure Kit, if venting, power, emptying and local approval fit your plans. Check the Nature’s Head Structure Kit on Amazon

The four toilets here separate urine from solids and need no flush-water supply. That does not mean no wastewater plan: Separett uses a urine drain, and sinks/showers still need their own approved drainage. A small collection bin is not a guarantee of finished, safe compost. Separett explicitly says its waste is not composted when the bucket is emptied. Compare the containers, ventilation, power and approved disposal route before choosing a toilet for a cabin, van or boat.

Confirm the whole sanitation plan: ask your health department or building official about the exact toilet, solid-waste handling, urine outlet and sink/shower graywater. The EPA’s September 1999 fact sheet explains these issues; it does not establish current approval for your property. Separett warns that local rules may forbid its illustrated urine outlets. Do not assume emptied waste can go straight into a garden or household trash.

Composting Toilets Compared

Scroll sideways to compare all columns. Model names stay visible; keyboard users can focus the table and use the arrow keys.

Toilet	Use	Urine handling	Solids capacity (maker)	Agitator	Power	Size / weight
Nature’s Head	Cabin, tiny home	2.2 gal bottle	60–80 uses	Hand crank	12 V fan; kit adds 110 V adapter	21 H x 20 W x 19 D in.; kit 28 lb, toilet alone 23 lb
Separett Villa 1255-01 (buying link withheld)	Cabin, house with a drain route	Drain hose to greywater drain, infiltration or container	23 L bagged container; 4–6 weeks for four people	None; container rotates when you sit	12 V fan, 2.5 W; 110–240 V adapter	26.5 L in.; sizing and weight conflict—see Villa notes
OGO Origin	Van, boat, small bath	2.4 gal bottle with full light	25–30 uses	Push-button electric	12 V DC	18-3/8 H x 16 W x 15 D in.; 28 lb
TROBOLO WandaGO	Camping, occasional	4.6 L container	6.5 L container	None	None	4.2 kg (TROBOLO)

Figures come from the exact maker documents below. The Nature’s Head kit and toilet-only pages give different weights; Separett’s current U.S. manual/page/drawing disagree on sizing. Confirm clearance and the exact unit before a tight installation. On October 8, 2026, the three linked Amazon listings and the Creators API showed new units in stock from the makers’ stores. The Villa buying link is withheld because its regional kit identity is unresolved. Availability can change.

Bottle or Drain? Fan or No Fan?

Urine bottle (Nature’s Head, OGO): no urine drain to install, but a regular emptying job. Intervals below are maker estimates for the stated number of users, not a fixed promise.
Urine drain (Separett Villa): a 1-1/4 inch line that falls all the way to a greywater drain, infiltration or an outside container. No bottle, but you need a drain route, and Separett says local laws may forbid some or all of those options.
Fan-vented (Nature’s Head, Separett, OGO): needs a vent to outside and 12 volt or adapter power.
No fan (TROBOLO): portable and simple, for camping and occasional use.

Installation Notes From the Manuals

Plan the vent and access. The current U.S. Villa manual specifies 3-in. Schedule 40 PVC with about 3.5-in. outside diameter, up to 20 feet and three 90-degree elbows. Use a short route and fresh air near the toilet; the manual requires no other fan system affecting the same room. For OGO, allow overhead space to lift the solids bin and reach the urine bottle, not just its 15 x 16-in. footprint.
Plan a continuously falling urine line. Villa comes with a 6.6-ft hose. For longer runs the current U.S. manual calls for at least 40-mm internal diameter, while the U.S. product page says at least 1.5 in. Confirm the pipe size and winter protection for your installation with Separett; do not resolve differing instructions by guessing.
Maintain the urine line. The current U.S. Villa manual recommends regular drain cleaning and its Bio Drain Cleaner tablets. Follow the instructions for the exact unit instead of combining older vinegar schedules with the newer procedure.
Power. Nature’s Head and OGO run on 12 volt; on house power you need an adapter (included in the Nature’s Head Structure Kit, sold separately for OGO, per the makers).
Arrange approved waste handling. Emptying a bin is not proof of completed treatment. Separett describes separate storage/composting or approved incineration, subject to local rules. Establish that route before ordering; the toilet alone does not replace the rest of a dwelling’s wastewater system.

Best for Cabins and Tiny Homes

Nature’s Head Composting Toilet, Structure Kit

Self-contained, waterless, urine-diverting · solids bin about 60–80 uses · 2.2 gal urine bottle · hand-crank spider agitator · 12 V fan (kit adds a 110 V AC adapter) · 5 ft of 1-1/2 in. hose with ends · kit 28 lb; toilet-only page 23 lb · 21 in. H x 20 in. W x 19 in. D

Nature’s Head is a self-contained composting toilet: liquids go to a 2.2 gallon bottle in front, solids to a bin you mix with a crank, and a small 12 volt fan pulls air out through a vent hose. Nature’s Head lists about 60 to 80 solid uses before the bin needs emptying, depending on conditions and composting medium, in a toilet 21 inches tall. Its toilet-only page lists 23 lb; the exact Structure Kit page lists 28 lb.

The Structure Kit on Amazon is sold by the Nature’s Head store. The maker’s kit page confirms an AC adapter, shell vent/installation kit and 9 L coir bag. The linked Spider Handle kit listing specifies the 110 V adapter. These are kit extras; do not assume a toilet-only listing includes them. The listing says the solids bin typically lasts up to a month for two users, and the urine bottle needs emptying every 2 to 3 days. Nature’s Head’s warranty page covers the toilet and its components against defects in materials and workmanship for five years from the purchase date.

60–80 solid uses per bin, per Nature’s Head
No flush-water or urine-drain hookup
Kit adds AC adapter, shell vent parts and coir
Hand-crank agitator instead of a mixing motor

Urine bottle every 2–3 days, per the listing
You crank the agitator
21 in. tall, larger than the OGO

Verdict: Compare it for daily cabin use when you can vent outside, power the fan and regularly empty the bottle. Confirm your solid-waste route and local approval first; a kit does not settle those requirements.

Check the Nature’s Head Structure Kit on Amazon

Best With a Urine Drain (No Bottle to Empty)

Separett Villa 1255-01 (formerly 9215)

Urine diverts to a drain: greywater drain, infiltration or an outside container · 32 mm (1-1/4 in.) urine hose, 2 m (6.5 ft) · US model vents through 3-1/2 in. outside diameter pipe · 12 V fan, 2.5 W, 0.06 kWh per day, 110–240 V adapter included · 23 L solids container with compostable bags · 42 lb per current U.S. sources · 5-year warranty for private use

The U.S. maker page identifies Villa 1255-01 as the model formerly called 9215. Its urine goes down a drain instead of into a removable bottle. Separett’s manual says the urine drain can connect to an existing greywater drain, outside infiltration, an outside container or another approved solution, through a 32 mm (1-1/4 inch) hose that must fall the whole way. It also warns that local laws may forbid some or all of those options. Solids drop into a 23 liter container lined with a compostable bag, and Separett says the fan must run all the time to keep the toilet odor-free.

Separett lists the fan at 12 volts, 2.5 watts and 0.06 kWh a day, and says it suits battery and solar power; a 110 to 240 volt adapter comes in the box. For a household of four in full-time use, Separett says the solids container needs changing about every 4 to 6 weeks. The current U.S. manual and maker page list 42 lb; the Amazon listing gives 34 lb. Do not use the listing weight to plan handling or identify the regional kit. The manual text gives 18-in. width and 21.3-in. height; its drawing says 18.5 and 21 in., while the U.S. page says 18.5 and 21.3 in. Confirm the unit and template with Separett before a tight fit. The manufacturer says the bucket contents are not composted when emptied, so arrange approved handling beyond the toilet.

The current U.S. manual gives a 5-year product warranty; U.S. terms give the fan 3 years, commercial use 1 year and no rental coverage. Those terms cover approved replacement parts/standard shipping, excluding labor and related service costs unless law requires otherwise. The manual describes authorized labor/material coverage differently. Confirm applicable coverage with Separett Inc. before relying on a repair allowance; keep proof of purchase and follow the claim procedure.

No urine bottle: drains by gravity, per Separett
Fan runs on battery, solar or the included adapter
Bagged 23 L solids container
5-year warranty for private use, per Separett

Needs a urine drain route; local rules decide where it can go
Fan must run all the time, per Separett
No warranty in rental use, 1 year in commercial use, per Separett
19 kg, the heaviest toilet here, per the current manual

Verdict: Compare it where a gravity urine outlet is approved and the fan can run continuously. A collected-urine tank still needs emptying, and solids still need separate approved handling; do not choose it solely to avoid a bottle.

Buying link withheld: The listing identifies model 1255-01 but also gives part number 1123-01. The current Separett manual distinguishes Villa US 1255 from Villa CA 1123, with different included pipe fittings. We cannot confirm which regional kit that listing supplies. Confirm the exact kit and included connectors with Separett before ordering; the U.S. installation guidance here applies to model 1255.

Best for Vans, Boats and Tight Bathrooms

OGO Origin Compact Composting Toilet

15 in. D x 16 in. W x 18-3/8 in. H · seat height about 17 in. · push-button 12 V electric agitator · liquid sensor lights the button when the bottle is nearly full · 2.4 gal urine bottle · solids bin about 25–30 uses · 3 ft vent hose per OGO, fan ventilation per the listing · 28 lb empty · 12 V DC (adapter needed for 110 V)

OGO built the Origin around a small footprint: 15 inches deep and 16 wide, per OGO. Instead of a crank, a push button runs a 12 volt electric agitator, and a liquid sensor lights the side button when the 2.4 gallon urine bottle is nearly full. OGO lists about 25 to 30 uses for the solids bin.

OGO says the urine bottle needs emptying every 2 to 3 days for one user, or every 1 to 2 days for two. It runs on 12 volt DC, so it fits van and boat electrical systems; on house power you need a power adapter, sold separately, per OGO. The Amazon listing is sold by the OGO store. OGO’s placement guidance requires overhead room to remove the solids bin and access the urine bottle; its base dimensions alone do not prove it fits.

Smaller footprint than the Nature’s Head, per the makers
Push-button agitator
Liquid-full indicator
12 V for vans and boats

25–30 solid uses, fewer than Nature’s Head
Bottle every 1–3 days, per OGO
Needs an adapter for 110 V

Verdict: Compare it for a tight van or boat installation when the power, exterior vent and overhead emptying access fit. Choose the smaller solids bin knowingly; frequent use brings more emptying work.

Check the OGO Origin on Amazon

Best Portable (No Power)

TROBOLO WandaGO Portable Composting Toilet

Urine-diverting, no water, chemicals or electricity · 6.5 L solids and 4.6 L liquids containers · seat height 12.0 or 17.2 in. · 150 kg load rating per TROBOLO (listing: 330.7 lb) · 4.2 kg per TROBOLO (listing: 10.4 lb) · lid closes for travel

The WandaGO is a portable separating toilet for camping and weekend use. TROBOLO lists a 6.5 liter solids container and a 4.6 liter liquids container, a stacking seat that sits at about 12 or 17 inches, and a load rating of 150 kg. It needs no water, chemicals or electricity. Use natural litter and a liner as instructed, place it on a flat surface, and plan separate container emptying. Its EU maker page’s trash/fertilizer suggestions do not establish permission at your U.S. destination.

Its numbers are small on purpose: TROBOLO gives 10 to 20 urine uses and 8 to 12 solid uses before emptying, and recommends emptying the solids container every 5 to 10 days. Note one difference between documents: TROBOLO’s page gives the weight as 4.2 kg, about 9.3 pounds (our arithmetic), while the Amazon listing says 10.4 pounds.

No power, water or chemicals
Two seat heights
Light and portable
Lid closes for travel

8–12 solid uses, per TROBOLO
No vent fan
Weight listed two ways

Verdict: Compare it for short trips when a fan/power installation is impractical and frequent emptying is manageable. Confirm allowed disposal where you travel; it is a portable separating toilet, not a guarantee of finished compost.

Check the TROBOLO WandaGO on Amazon

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Before You Buy

Confirm approval: exact toilet, solid-waste handling, urine outlet and graywater system for the dwelling or destination.
Count users and days. Capacity is not a treatment guarantee. The smallest container may be enough for short trips; full-time use changes the emptying job.
Choose bottle or approved drain. Bottles and outside urine tanks need emptying; a drain needs the correct uninterrupted fall and allowed outlet.
Measure use and maintenance access. Allow vent/pipe room, continuous fan power where required, and space to remove containers. Resolve the Villa sizing/source differences before fitting it.
Check the exact package and warranty. Nature’s Head kit extras differ from a toilet-only listing; OGO needs a separately sold household power adapter. Villa battery/cables are not included, and rental use is excluded from its warranty.

Have a sewer or septic connection after all? See our toilet picks, or for a basement bathroom below the sewer line, our upflush toilet picks.

FAQ

Are composting toilets legal?

Approval depends on the location, exact toilet and complete wastewater/waste-handling plan. Ask your local health department or building official before installing one in a dwelling. The EPA’s September 1999 fact sheet is background, not proof of current approval. Emptying a bin does not mean its contents are finished, safe compost; confirm allowed handling of solids, urine and sink/shower graywater.

Do composting toilets smell?

The makers say urine diversion and a vent fan control odor: Nature’s Head, OGO and Separett all separate liquids and run a fan out through a vent. The EPA says improper maintenance can lead to odor problems, so empty and maintain it on schedule.

How often do you empty a composting toilet?

It depends on users, conditions and the container. Nature’s Head lists about 60–80 solid uses; its kit listing estimates bottle emptying every 2–3 days. OGO lists 25–30 solid uses and bottle emptying every 2–3 days for one user or 1–2 days for two. Villa’s U.S. manual estimates 4–6 weeks for four full-time users, but a urine collection tank still needs emptying. These are estimates, not treatment times.

Does a composting toilet need a vent?

The Nature’s Head, OGO and Villa models here need exterior ventilation. Nature’s Head includes 5 ft of 1-1/2-in. hose; OGO lists 3 ft. Villa’s current U.S. manual specifies 3-in. Schedule 40 PVC with about 3.5-in. outside diameter, up to 20 ft and three 90-degree elbows. Use the exact installation instructions and fresh-air requirements. TROBOLO WandaGO has no vent fan.

Can a composting toilet handle greywater?

No. The EPA says composting toilets must be used with a graywater system in most cases. Sinks and showers still need their own drain. Separett says its urine line can connect to an existing greywater drain, and that local rules may forbid it.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia journeyman plumber. This comparison uses the linked maker documents and exact listings; it does not claim hands-on testing. On October 8, 2026, the three linked Amazon listings and the Creators API showed new units in stock from the makers’ stores. Availability can change; the Villa listing remains unlinked because its regional kit identity is unresolved. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.

Sources

Your waterless toilet shortlist

Compare Nature’s Head for bottle-based cabin use, Villa for an approved urine-drain route, OGO for a tight powered/vented installation with emptying access, and WandaGO for short trips without a fan. Keep the smaller option when it covers your use. Confirm the solid-waste route, urine handling and local approval before ordering; sinks and showers still need their own drainage.