A global leader since 1971
Sun-Mar™ waterless composting toilets for off-grid New Zealand
No septic, no mains water, no odour. Trusted worldwide and supported here by WCTNZ® — find the right Sun-Mar™ for your home, bach or cabin.
NZ supply & support·AS/NZS 1546.2:2008 certified models·Composting since 1971
Off-Grid Versatility
EnvironmentallyFriendly
Innovative Design
Versatile Models
Proven Reliability
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.
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.
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.
Which system type suits you?
Sun-Mar™ offers more choice than any other composting toilet in New Zealand, and three questions narrow the whole range down: is the unit all in the bathroom or under the floor, do you want it fully waterless or with a small flush, and does your site have mains power?
Choice 1 · where the unit sits
Option A
Self-contained
Everything in one unit, in the bathroom
The toilet and the composting drum are a single unit that sits on the floor. No underfloor space, no plumbing run — it goes almost anywhere, which is why it suits baches, cabins, sleep-outs, tiny homes, RVs and boats. Always waterless.
- GTG
- Spacesaver 240
- Compact 240
- Excel 240
- Excel NE
Option B
Central system
Pedestal in the bathroom, composter under the floor — our Centrex™ line
A pedestal sits in the bathroom and the composting chamber is tucked away below the floor, so the bathroom looks conventional and the chamber can be much larger. That means longer composting cycles, bigger capacity and usually one compost removal a year. Needs accessible space under the floor.
- Centrex 2000
- Centrex 3000
- AirFlow or MicroFlush
- 240 V or non-electric
Choice 2: waterless (AirFlow)
No water at all. Waste falls straight into the BioDrum™ and composts — nothing to plumb in, nothing to freeze, nothing to run dry. Every self-contained model is waterless, and so is every Centrex™ A/F.
Best for: off-grid sites, tank water, cold or remote locations.
Choice 2: low-flush (MicroFlush)
A familiar flush on about a pint of water instead of six or more litres. Available on the Centrex™ central systems only, and it lets you place the composter away from the bathroom — with multiple pedestals if you need them.
Best for: main homes and sites with reliable water, where a normal-feeling flush matters.
Choice 3: no mains power? Ask for a Non-Electric (N/E)
N/E models run with no mains power at all — no fan or heater as standard — so they work on genuinely off-grid sites. Available as the self-contained Excel NE and across the Centrex™ 2000 and 3000 NE range, in both waterless and low-flush versions.
Self-contained systems
One unit does everything and sits on the bathroom floor — no sub-floor space, no plumbing run, easy to install and maintain. Sizes run from the tiny GTG up to the best-selling Excel 240, with a non-electric (N/E) option for sites with no mains power.
Water-free and odour-free — a clean long-drop alternative for a cosy cabin, an RV, a remote New Zealand bach or an off-grid lifestyle block.
Sun-Mar™ GTG
For 1–2 people full-timePart-time or holiday use: 3–4 people
Sun-Mar’s smallest and most economical unit: fast to set up, fully self-contained and vented for odour-free use. Built for places a conventional toilet can’t go — RVs, boats, tiny homes, cabins, farms, workshops and sheds.
Full-time capacity depends on the number of chambers.
Sun-Mar™ Spacesaver 240
For 1 person full-timePart-time or holiday use: 3 people
The compact powered model for very small spaces — baches, sleep-outs, cabins and tiny homes with reliable power. Full BioDrum™ composting and the patented three-chamber design in the smallest powered footprint Sun-Mar makes.
Special order — ask us about current lead times.
Sun-Mar™ Compact 240
For 1–2 people full-timePart-time or holiday use: 3–4 people
A low-profile unit that keeps a clean bathroom look while still running the full two-stage composting cycle inside the unit. Suited to light residential use and medium cottage or holiday use.
Sun-Mar™ Excel NE
For 2–3 people full-timePart-time or holiday use: 5–6 people
Excel capacity with no mains power at all: no fan and no heater as standard, so it runs on sites with no reliable supply. The straightforward answer for off-grid cabins, baches and remote builds.
Sun-Mar™ Excel 240
For 3–4 people full-timePart-time or holiday use: 6–7 people
Sun-Mar’s best-known model and the high-capacity choice for homes, cottages, cabins and light commercial use where power is available. Valued for simple operation and NSF-certified performance.
Central systems — the Centrex™ line
A pedestal sits in the bathroom while the composting chamber is tucked discreetly under the floor. The bigger chamber means a longer, uninterrupted composting cycle, higher capacity and typically one compost removal a year — the choice for busy holiday houses, family homes and off-grid living.
Centrex™ is also the only range here with a micro-flush (low-flush) option: a familiar flush on about a pint of water, which lets you place the chamber away from the bathroom and add more than one pedestal.
Sun-Mar™ Centrex 2000 AirFlow 240
For 4–5 people full-timePart-time or holiday use: 7–8 people
Underfloor composter with a straight-fall waterless pedestal: a longer composting cycle and a larger compost volume than the self-contained units. Comfortably handles a seven-person holiday house.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 2000 MicroFlush 240
For 3–4 people full-timePart-time or holiday use: 6–7 people
The same underfloor chamber with a micro-flush pedestal — a flush-style feel on about a pint of water, the freedom to site the composter away from the bathroom, and the option of more than one pedestal.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 2000 NE AirFlow
For 4 people full-timePart-time or holiday use: 6–7 people
The off-grid version of the 2000 A/F: same larger underfloor chamber and waterless pedestal, designed for low-power or no-power installations. Typically one compost removal a year in holiday-house use.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 2000 NE MicroFlush
For 3 people full-timePart-time or holiday use: 5–6 people
Micro-flush comfort without mains power: the familiar pedestal experience combined with an underfloor chamber that runs off-grid. For medium to heavy seasonal use or a light permanent household.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 3000 AirFlow 240
For 6–7 people full-timePart-time or holiday use: 10–11 people
The largest waterless Centrex: a continuous-rotation drum and the biggest compost volume in the range, for busy holiday houses and medium residential use with a straight-fall waterless pedestal.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 3000 MicroFlush 240
For 5–6 people full-timePart-time or holiday use: 9–10 people
The largest micro-flush Centrex: maximum composting capacity with a flush-style pedestal and the freedom to place the chamber where it suits the build.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 3000 NE AirFlow
For 5–6 people full-timePart-time or holiday use: 9–10 people
High-capacity composting for off-grid sites: the long 3000-series drum and a waterless pedestal, running on low voltage instead of mains power.
Special order — ask us about current lead times.
Sun-Mar™ Centrex 3000 NE MicroFlush
For 4–5 people full-timePart-time or holiday use: 8–9 people
The largest low-flush system that runs without mains power — heavy cottage or medium residential use where underfloor installation is possible and power is limited.
Special order — ask us about current lead times.
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 wastewater option in New Zealand, covered by AS/NZS 1546.2:2008 – On-site domestic wastewater treatment units – Waterless composting toilets. The Sun-Mar Centrex 3000 systems are listed on the current StandardsMark schedule for that standard (licence SMKH25591); for the other models we supply the manufacturer's product documentation. Either way certification supports your application rather than approving the site — the council still assesses your installation, and requirements vary by district, so talk to them early and ask us for the paperwork.
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.
Certification & council consent
What your council will ask for
Waterless composting toilets are a recognised on-site wastewater option in New Zealand, not a workaround — they have their own product standard in the same family as septic tanks. Here is exactly where a Sun-Mar™ stands, and what we can send you for the consent application.
The standard
AS/NZS 1546.2:2008
On-site domestic wastewater treatment units — Waterless composting toilets. This is the product-level standard for composting toilets, one of three recognised treatment-unit pathways in the AS/NZS 1546 family, alongside septic tanks (1546.1) and aerated systems (1546.3).
AS/NZS 1547 sits over it as the wider framework for how on-site domestic wastewater is designed and managed.
What is listed today
Centrex™ 3000 on the StandardsMark schedule
The Sun-Mar™ Centrex™ 3000 systems — 3000 A/F, 3000 A/F NE, 3000 flush and 3000 NE — are listed on the current StandardsMark schedule for AS/NZS 1546.2:2008. For any other Sun-Mar™ model we supply the manufacturer’s product documentation instead, so ask us what exists for the model you are looking at.
See the certificate scheduleWhat we can send you
The documents for your application
The certificate schedule, manufacturer product documentation, the installation manual and the model specifications — the product side of a building consent application, in one go.
Tell us your council and the model you are considering, and we will point you at the right files rather than a general brochure.
Ask for consent documentsCertification is not the same as approval
A listed product supports the product side of your application — it does not approve the site. Your Building Consent Authority still assesses the installation, the building work, ventilation, the liquid waste pathway, the user load and the consent conditions for your specific project, and requirements vary by district. Talk to your council early; use us for the paperwork.
Not Sure Which Sun-Mar™ You Need?
Tell us how many people use the bathroom and where it’s going — we’ll point you to the model that suits, and answer the council and off-grid questions before you buy.
- A recommendation based on real use, not a spec sheet
- Straight answers on consent, venting and power
- Supplied, installed and supported here in New Zealand
- Phone 0800 022 027
- Email sales@wctnz.co.nz
- Supplied & supported in New Zealand by WCTNZ®
Copyright © 2023 WCTNZ™ | Waterless Composting Toilets NZ. All rights reserved. All prices are entered excluding tax. Excluding shipping
This page uses: GA4 / Ads