The Tool Desk
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What to check before choosing a composting toilet
Composting toilets use little or no water and generally avoid a municipal sewer or septic connection, but the label covers different system designs. NSF describes the process as aerobic decomposition in an enclosed environment. That does not mean every waterless toilet produces finished, safe compost under every use condition.
- Installation setting: Identify whether the unit will be installed in a fixed home, cabin, RV, boat, van or tiny home. Space, mounting, vent routing and available power differ.
- System design: Decide whether you want a self-contained unit or a urine-diverting design that requires separate liquid storage or plumbing.
- Occupancy pattern: Match the manufacturer’s capacity description to continuous residential use or occasional weekend and vacation use. These ratings are not interchangeable.
- Waste handling: Account for the model’s required liquid routing or emptying, solids handling, bulking material where applicable, cleaning and maintenance.
- Approvals and disposal: Check local plumbing, environmental-health and waste-handling rules before purchase. Requirements vary by jurisdiction.
For an overview of how the category is defined, see NSF’s explanation of composting toilets.
Self-contained or urine-diverting?
Self-contained systems
A self-contained toilet handles waste within the unit. It may be a better fit when you want an integrated system, but it still needs the model’s specified installation and maintenance, and its capacity depends on the manufacturer’s stated use pattern. Sun-Mar’s 2026 lineup includes the Excel, Excel NE, Compact and SpaceSaver self-contained models.
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#1 Best Overall
- No one - and I mean no one - will beat my customer service and individual support
- Easy to install by any reasonably handy person.
- Absolutely No Odor. No Maintenance. 5 Year Warranty.
- Huge Capacity. 2 people using full time will empty every 4-6 weeks. Easy empty in 5 minutes.
- A vast improvement over older composting toilet designs. This one works!
Urine-diverting systems
Urine-diverting models separate liquid from solids, so the installation must account for where the liquid goes—such as a separate container or plumbing arrangement, depending on the model and installation. Nature’s Head lists urine-diverting variants, and Sun-Mar’s 2026 brochure includes the GTG. Confirm the specific model’s instructions and local rules for liquid handling rather than assuming a single arrangement applies across the category.
Documented models to consider
These are options with manufacturer documentation, not a ranked “best” list. The available evidence does not provide independent comparative testing of odor, durability, ease of cleaning or real-world capacity.
Rank #2
- SMALLEST FOOTPRINT FOR TIGHT BUILDS (15"x16") Designed for Sprinter/Transit vans, tiny homes & boats where space is everything. The OGO fits corners other composting toilets can’t—no bulky side crank, no redesigning your bathroom. More legroom, cleaner layout, modern appliance look.
- PUSH-BUTTON ELECTRIC AGITATOR = ZERO CRANKING 12V motor mixes solids with one tap—no manual handle, no mess, no chore after every use. Better breakdown, better odor control, effortless daily routine. Feels like a real toilet, not a campsite workaround.
- URINE-DIVERTING = NO BLACK TANK SMELL Liquids separate to a 2.4-gal bottle while solids stay dry in the rear bin (25–30 uses). Dry waste = no sewage odor, safer storage, and confident hosting in your van or tiny home.
- MADE FOR REAL OFF-GRID LIFE Built in the USA from durable polypropylene. Quiet fan ventilation, low 12V power draw, simple emptying, and serviceable parts. Perfect for full-time van lifers, retro-fit RV owners, marine cabins, and off-grid couples.
- MODERN DESIGN, NOT PORT-A-POTTY VIBES Clean Scandinavian-style aesthetic that belongs in a premium build. Go anywhere, smell nothing, crank nothing—upgrade your rig with the “smart toilet” built for civilized freedom.
| Brand and models | Design and stated fit | What to verify |
|---|---|---|
| Nature’s Head: standard toilet, Weekender and urine-diverting variants | The manufacturer lists use in RVs, boats, cabins, tiny homes and other off-grid settings. | Use the manual for the exact model to plan exterior venting, fan power, mounting and any liquid handling. The manufacturer describes 12V DC or household power depending on the installation. |
| Sun-Mar: Excel, Excel NE, Compact, SpaceSaver and GTG | The 2026 brochure lists the first four as self-contained models and GTG as urine-diverting. Capacity descriptions vary by model and by continuous versus weekend or vacation use. | Compare only ratings that match your expected occupancy pattern. Sun-Mar says its self-contained residential/cottage units are certified to NSF/ANSI Standard 41; confirm the precise model in NSF’s current directory. |
See Nature’s Head’s model lineup, its 2026 product brochure and Sun-Mar’s US product range for current model-specific information. Manufacturer capacity claims are tied to their stated patterns of use; do not compare seasonal use figures as though they were continuous residential ratings.
Certification: what it tells you
NSF says certification to NSF/ANSI Standard 41 evaluates six areas: capacity, including occasional overload; odor; bacterial content of output; truthful claims and labeling; restricted access during testing; and parallel field testing. Certification is useful evidence, but check that the mark and certification cover the exact model you plan to install.
Rank #3
- DESIGNED FOR THE ADVENTURER - No Electric, No Plumbing, No Hassle. The NOMAD is the simple, affordable compost toilet solution built for rugged environments. No power source or wiring required—perfect for truck campers, pop-up tents, primitive camping, and remote field setups.
- ODOR FREE URINE DIVERTING SYSTEM - Built with a proven separation design that keeps liquids and solids apart to prevent odor—without chemicals, black tanks, or septic connections. Stay longer outdoors without relying on dump stations or chemical toilets.
- PORTABLE AND SPACE SAVING - Compact footprint fits in truck beds, car trunks, TentBox-style rooftop tents, rental camper vans, small boats, and temporary field shelters. Lightweight and easy to move, store, load, or deploy wherever nature takes you.
- SIMPLE BAG SYSTEM - No special liners required. The system works with widely available 8-gallon bags for easy clean-up and fast campsite turnaround. A great option for day boaters, weekend adventurers, hunters, and guides.
- DURABLE, LOW MAINTENANCE - Made for mud, dust, weather, and repeated weekend trips. Just add composting medium, use, tie off the bag, and dispose per local guidelines. Made with rugged materials and manufactured with care in the USA.
Sun-Mar’s Excel product page reports that NSF tested that model at maximum capacity for six continuous months; this is a claim reported by Sun-Mar. It should not be generalized to other models. Certification requirements for bacterial content also do not establish that local authorities permit the output to be applied as fertilizer. Follow local disposal rules.
NSF advises consumers to look for the NSF mark on the product to verify independent certification to applicable public-health standards. Read more at NSF’s composting-toilet certification overview and review Sun-Mar’s Excel product details.
Rank #4
- Item Category: Toilet Seat
- Item Trademark: Nature's Head
- manufacturer: Nature's Head Inc.
- Item shape: Foot-Spider
Plan installation before buying
- Choose the exact model. Review the manufacturer’s manual and installation guide for that model before planning openings or ordering hardware.
- Map the vent route and power. Nature’s Head instructs installers to plan exterior venting and fan power, with 12V DC or household power depending on installation. Sun-Mar specifies a 2-inch vent connection for the Excel; that dimension should not be assumed for other models.
- Check mounting and liquid routing. Determine how the unit will be secured and, for a urine-diverting design, where liquid will be stored or routed. Do not drill mounting, vent or drain openings until the selected model’s instructions have been reviewed.
- Confirm local approval and handling rules. Ask the relevant plumbing or environmental-health authority about installation approval and requirements for liquid discharge and finished material. Florida, for example, maintains a state-specific approved-product list; it was last reviewed December 19, 2023, so confirm current requirements directly with the state or local authority.
Use Nature’s Head’s manuals and installation guides for its models, and the Sun-Mar Excel page for that model’s connection details. Florida’s list is available from the Florida Department of Environmental Protection; it does not establish rules for other jurisdictions.
Maintenance and waste handling
There is no category-wide emptying interval or universally permitted way to dispose of finished output. Follow the exact model manual and applicable local requirements for liquid, solids and any finished material. Do not assume that a toilet marketed as composting makes output safe or legally usable as fertilizer in every setting.
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- Urine-Separating Compost System: Waterless composting toilet with urine diverting technology for off-grid use without additives or mixing required
- High-Capacity Design: Spacious construction accommodates extended use between emptying cycles, suitable for residential and remote applications
- No Water Required: Completely waterless operation eliminates the need for plumbing connections and conserves water resources
- Versatile Installation Options: Suitable for homesteads, converted school buses, cottages, cabins, and other off-grid living spaces
- Low Maintenance Operation: Simple design requires no chemical additives, mixing, or complex maintenance procedures for hassle-free composting
Care instructions can also be model-specific. Nature’s Head support materials recommend spraying a 1:1 vinegar-and-water solution in the bowl and urine drain area to help prevent buildup. Treat this as that manufacturer’s guidance, not a universal cleaning rule; see Nature’s Head support resources.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
