A global leader since 1971
Waterless composting toilets that work off-grid — no septic, no mains water, no odour.
Trusted worldwide, supplied and supported here in New Zealand by WCTNZ®. Find the right Sun-Mar™ for your home, bach or cabin.
NZ supply & support·Certified to AS/NZS 1546.2:2008·Composting since 1971
Off-Grid Versatility
EnvironmentallyFriendly
Innovative Design
Versatile Models
Proven Reliability
Testimonials
Carol
- Coromandel
I bought the Sun-Mar GTG compost toilet after researching ease of installation and use.
It’s installed in my caravan located in Coromandel. We have limited water supply, so another reason for choosing a compost toilet.
I’d recommend the Sun-Mar GTG. It meets all our requirements perfectly. From its design to easily to keep clean, I’ve had no issues with it. Plus, had no issues with installation – found it very easy to install.
Tracey
- Canterbury
We chose the Sun-Mar GTG toilet for our rural new build in Twizel (Mackenzie Region). We went for a composting/waterless option as a cheaper option than septic tanks.
The toilet is fantastic! I thought there would be a slight odour, but there is absolutely zero. Very easy to empty and clean, and the minimal design looks amazing in our lovely new bathroom.
Plenty of our guests have been impressed and are looking at one of these units for sleepouts and houseboats. 100% recommend this product!
About
Sun-Mar™ is a well-established brand of composting toilets that has been in the business of turning waste into compost since the 1970s. Perfect for those who live off the grid, Sun-Mar™ offers a range of composting toilets that are suitable for use in the outback, on the road, or anywhere you may find yourself in need of alternative toileting solutions.
With their expertise in composting technology, Sun-Mar™ has developed toilets that are both efficient and effective, making it easy to manage human waste in a sustainable and environmentally-friendly manner. Available in both self-contained and split-system designs, there is a Sun-Mar™ waterless composting toilet for every need and every build. So, if you’re looking for a composting toilet that is tailored to your unique off-grid lifestyle, Sun-Mar™ is the brand to trust.
Technology
At Sun-Mar™ New Zealand, we know that the best way to garner environmental benefits from composting toilets is by making composting easy for our customers.
We understand that composting toilets must excel in three distinct processes: rapid and odourless composting, safe and easy handling of the finished compost, and efficient liquid management. This is why our systems are engineered to achieve these goals to perfection.
At the heart of Sun-Mar™ success is our unique Three-Chamber System design, consisting of the Bio-drum™, a Finishing Drawer, and an Evaporation Chamber. By staging the composting process, this extraordinary design creates the ideal composting environment at every stage.
The Bio-drum™ combines warmth, moisture, organic material, and oxygen to facilitate swift and efficient breakdown of waste by aerobic microbes. Excess liquid is automatically drained through a specialized screen into the Evaporation Chamber, ensuring optimal composting speeds. The rotating Bio-drum™ ensures even mixing and oxygenation throughout the compost pile – this thorough aeration is key to odourless, rapid waste decomposition. Once the compost has matured in the Finishing Tray, it is ready for reintegration into the environment.
Sun-Mar™ systems come in both self-contained (on-floor) and split-system designs, making sure there is a toilet for every application – whether it be an RV, a tiny home, a residential house or a bigger commercial operation anywhere in New Zealand.
Thanks to our state-of-the-art technologies, Sun-Mar™ is recognized as a leader in composting toilets, and holds a reputation for quality, reliability, and sustainability. Our systems are used by homeowners, businesses, and organizations around the world, who appreciate our commitment to creating a healthier planet.
At the heart of every Sun-Mar™: the BioDrum
Every Sun-Mar unit is built around the patented BioDrum — the rotating chamber where composting actually happens. You turn a handle every few days and the drum tumbles the waste, mixing it with oxygen and bulking material so it breaks down quickly and evenly. There’s no crust to break up and no wet pockets — the part people quietly worry about is a few seconds of turning a handle.
History
1971
1979
In 1979, Sun-Mar™ upped the ante again with their new, patented design of the Three -Chamber composting system with the rotating Bio-drum™ for composting, a chamber for evaporating liquids, and a separate chamber for compost finishing. These three compartments allowed the system to create optimal environments for each function.
Today
Today, Sun-Mar™ is a global leader in composting toilets, supplying a wide range of models worldwide. Our range includes both split systems and self-contained systems, and each one is distinguished by its innovative design, superior technology, and manufacturing quality.
Self-contained Systems
Offered in a range of sizes to fit your unique space, our self-contained systems are an incredibly versatile option that can be installed absolutely anywhere. There is no need for sub-floor space, and these systems are easy to install and maintain, with non-electric (N/E) options that run without mains power.
Whether you reside in a cosy cabin, roam in an RV, seek solace in a remote New Zealand bach, or have a lifestyle property in an off-grid location, we have a self-contained composting toilet system that will fit seamlessly into your lifestyle. Water-free and odour-free, these systems guarantee a consistently fresh toileting experience, no matter where your adventures take you.
Sun-Mar™ GTG
Full-time users: 1-2 people
Part-time users: 3-4 people
*depending on number of chambers
Sun-Mar™ Compact 240
Full-time users: 1-2 people
Part-time users: 3-4 people
Split Systems
Sun-Mar’s™ Split Systems are the ultimate choice for those who value self-sufficiency and independence in off-grid living. Designed to handle high-use, these systems feature Sun-Mar’s™ innovative Three-Chamber design to optimize composting and keep maintenance low. Whether you’re establishing an off-grid haven, a remote survival shelter, or simply prefer an eco-friendly approach to waste management, Sun-Mar’s™ Split Systems are the ideal choice.
Combining practicality with style, our split system setup sees a lovely pedestal sit in your bathroom, while the composting chamber is tucked discreetly beneath the floor. This ingenious design provides an excellent look, a comfortable toileting experience, and an effective, uninterrupted composting cycle. Plus, these are the only systems on the market available with a micro-flush (low-flush) option – perfect for sites where water availability is not an issue, micro-flush allows you to place the composting chamber away from the bathroom and gives you more flexibility in your design.
Sun-Mar™ Centrex 2000 AirFlow 240
Full-time users: 4-5 people
Part-time users: 7-8 people
Water-free toilet connection
Sun-Mar™ Centrex 2000 MicroFlush 240
Full-time users: 3-4 people
Part-time users: 6-7 people
Ultra-low flush toilet & multi-pedestal option
Sun-Mar™ Centrex 2000 NE AirFlow
Full-time users: 4 people
Part-time users: 6-7 people
Water-free toilet connection
Sun-Mar™ Centrex 2000 NE MicroFlush
Full-time users: 3 people
Part-time users: 5-6 people
Ultra-low flush toilet & multi-pedestal option
Sun-Mar™ Centrex 3000 AirFlow 240
Full-time users: 6-7 person
Part-time users: 10-11 people
Water-free toilet connection
Sun-Mar™ Centrex 3000 MicroFlush 240
Full-time users: 5-6 person
Part-time users: 9-10 people
Ultra-low flush toilet & multi-pedestal option
Sun-Mar™ Centrex 3000 NE AirFlow
Full-time users: 5-6 person
Part-time users: 9-10 people
Water-free toilet connection
Sun-Mar™ Centrex 3000 NE MicroFlush
Full-time users: 4-5 person
Part-time users: 8-9 people
Ultra-low flush toilet & multi-pedestal option
Frequently asked questions
Do composting toilets smell?
No. A Sun-Mar is designed to be odour-free — a fan draws air down through the toilet and out a vent, so the bathroom stays fresh. The composting happens sealed inside the BioDrum, not in the room.
How often do I empty it?
Far less often than people expect. Inside the drum the volume reduces dramatically as it breaks down, so a finished tray only needs emptying every few weeks to a few months, depending on how many people use it. What comes out is dry, composted material — not sewage.
Will my council let me install one?
Composting toilets are a recognised on-site option in New Zealand. Sun-Mar units are certified to AS/NZS 1546.2:2008 — the Australian/New Zealand standard for composting toilets — and WCTNZ can supply the documentation councils ask for when you consent an installation. Requirements vary by district, so it's worth checking with your local council early.
Does it work off-grid, without power?
Yes. Sun-Mar makes Non-Electric (N/E) models that need no mains power at all — they use a natural vent and the hand-turned drum, which is exactly what remote and off-grid sites need. Electric models add a fan and small heater to speed composting where power is available.
Self-contained or central — which do I need?
A self-contained unit has the toilet and the composting drum in one piece, sitting on the bathroom floor — simple to install and ideal for baches, cabins and tiny homes. A central system places a larger composting unit below or away from the toilet (Sun-Mar's central model line is called Centrex) and suits full-time homes and higher use. Tell us your household size and we'll point you to the right one.
Waterless or low-flush?
Both compost the same way. Waterless (AirFlow) models use no water at all — best for true off-grid. Low-flush models use a small amount of water for a more familiar flush feel while still composting. If you want something closer to a "normal" toilet, low-flush is the one to ask about.
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