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Perfect for medium to heavy seasonal or medium residential use, the Centrex 3000 allows for both a longer composting cycle and the largest compost volume

Featuring Sun-Mar's™ patented Bio-drum™ technology, the Centrex is a true composting system that processes the compost in two stages within the unit itself.

The Centrex 3000 composting toilet works on a continuous flow design to maximize its capacity and improve the composting process. The rotation of the drum forces the compost along the length of the Centrex 3000 and into an auto-drop mechanism, which lets the compost fall into the collection housing. Unlike with the smaller Centrex 2000, the drum doesn’t have to be rotated backward for emptying. The drum handle can continually be rotated in a clockwise direction and allow the material to work along the drum and deposit in a separate collection box.

All Centrex 3000 electric units feature a 370-watt 120-volt thermostatically controlled heater in a sealed compartment beneath the unit coupled with the standard Sun-Mar 30-watt turbo fan and 2" vent stack. This heater assists in the evaporation of liquids, reducing the amount of effluent from the unit. The fan also removes any fresh odors from the unit, ensuring odor-free operation.

Capacity

Listed capacities refer to the number of people, on average, using the unit per day. Do not pick a unit that is below your capacity.

Certifications

AS/NZS 1546.2:2008 - On-site domestic wastewater treatment units - Waterless composting toilets

License Number. SMKH25591

Against the AS/NZS 1546.2

Under SAI Global

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Sun-Mar Composting Toilet Systems are CSA certified for electrical features under CSA file number LR55925

NSF/ANSI 41 Standard - Non-Liquid Saturated Treatment Systems

This system is Certified for liquid containment, odors, and solid end products

THERE IS ONLY ONE PERFORMANCE STANDARD FOR COMPOSTING TOILETS IN NORTH AMERICA. THIS IS NATIONAL SANITATION FOUNDATION NSF/ANSI STANDARD #41. 

Sun-Mar is certified by the NSF under this stringent standard. Testing is conducted for 6 months at an NSF recognized, independent testing laboratory under a strict test protocol. 

To be certified, the unit must operate odor-free at maximum capacity (including overload conditions) and produce clean, safe compost. 

What you need to know about Composting Toilets

As additional verification, NSF obtains and tests additional compost samples from randomly selected field operations, and conducts interviews with the users of these units. For verification, please check the NSF website. 

NSF International is a not-for-profit, non-governmental organization. It is the world leader in standards development, product certification, education, and risk management for public health and safety, and for 75 years has been committed to public health, safety, and protection of the environment. 

WCTNZ® is the exclusive authorized distributor of Sun-Mar™ composting toilets in New Zealand. All Sun-Mar™ products available through WCTNZ® are guaranteed authentic, include official manufacturer warranties, and come with comprehensive local customer support—making us New Zealand’s trusted source for sustainable, waterless composting toilet solutions.

Copyright © 2025 Waterless Composting Toilets NZ Limited (WCTNZ®). All short and long product descriptions and content are the property of WCTNZ® | Waterless Composting Toilets NZ. All rights reserved.

This content has been reviewed and approved by Dylan Timney, Managing Director of WCTNZ®, who brings over 17 years of composting toilet expertise and 16 years of experience in building and eco-construction in New Zealand.

Last reviewed: June 26, 2025