Updated PGDB guidance gives owners, suppliers and certifiers a more specific basis for assessing waterless composting toilets in self-contained vehicles. The focus is the product and its complete installation—not an automatic approval based on a toilet’s label.
Clearer guidance for a different toilet technology
The PGDB’s updated guidance note, dated 11 June 2025, addresses considerations when inspecting waterless composting toilets in self-contained vehicles. It supersedes the earlier note dated 17 April 2025; it is not the first recognition of these toilets in the regulatory framework.[1]
The note helps inspectors and certification authorities assess products whose operation differs from a conventional flushing toilet. It is guidance supporting the existing regulations, not a new product-certification standard or a blanket approval for every waterless toilet.
For owners, the useful outcome is greater clarity about the information an assessment needs: the exact product, its instructions and the way it is fitted and used.
WCTNZ®’s contribution
WCTNZ® contributed product and operating information during the consultation process. Our objective was to help the discussion reflect how waterless systems actually collect and manage waste, rather than apply assumptions drawn from an unrelated type of toilet.
That involvement supports our commitment to customer education and suitable system selection. It does not give WCTNZ® authority to certify a vehicle or imply that the regulator endorses every product we supply.
Product evidence and clear instructions belong in the assessment. The certification authority remains responsible for the vehicle’s certification decision.
What the installation must demonstrate
The base and emptying arrangement need to meet the fixed-toilet requirement. The chambers must be suitable for containing human waste, and the available capacity needs to support the vehicle’s certified occupants for the required three-day period.
The installation also needs to follow the manufacturer’s instructions. A toilet that is appropriate for one vehicle may not be suitable for another layout, occupancy or servicing arrangement.
For a customer preparing a vehicle, our recommendation is to ask the supplier for the current model-specific manual and discuss the mounting, access and removal method with the certification authority before the work is completed.
Ventilation is not simply optional
The 2024 amendments distinguish permanently fixed wastewater tanks from removable chambers. That distinction does not override a toilet manufacturer’s specified venting or fan requirements. The 2025 guidance addresses the manufacturer’s installation requirements directly.[1][2]
When comparing systems, ask how the proposed model manages airflow and what parts of that arrangement must be installed. Avoid relying on a general statement that all composting toilets either require the same external vent or require none.
Containment is not the same as finished compost
Collected solids are not automatically fully composted or safe to use as a garden material. The PGDB note distinguishes containment in a vehicle from the further processing that may be needed and provides responsible-disposal guidance.[1]
That is an important part of ownership. A toilet can conserve flushing water while still requiring a practical plan for liquids, solids, cleaning and handling. The owner also needs to manage the rest of the vehicle’s wastewater.
For the precise capacity, storage and disposal guidance, use the current official note rather than relying on a short retailer summary. Disposal facilities must also be suitable for the material being taken to them.
The useful distinction: a waterless toilet may reduce flushing-water demand, but it does not remove the responsibility to contain, handle and dispose of waste safely.
Benefits should be matched to actual use
For some travellers, waterless sanitation offers a useful way to conserve stored water and choose a different waste-handling routine. Whether that is a good fit depends on the product, the trip and the owner’s preferences.
We recommend comparing usable capacity, servicing access, ventilation, consumables and the practical disposal route. Claims about weeks of use, odour control or reduced emptying frequency should be supported by the selected model and expected occupancy, not assumed for the whole category.
The same approach applies to maintenance. Clear instructions and an installation that can be accessed for cleaning are more useful than a generic promise of a maintenance-free system.
Read the guidance and take it to the assessment
The current PGDB information hub and the NZMCA inspector resource page provide useful starting points. The June 2025 PDF below is a PGDB-authored note hosted by NZMCA.
Use it together with the applicable regulations, the general vehicle inspection guidance and the manufacturer’s instructions. Where a question remains, resolve it with the responsible certification authority.
Guidance document and supplied page images
Open the PGDB guidance note dated 11 June 2025 (PDF)
The five images below are the reproductions supplied with the existing WCTNZ® article. Their image files have been retained unchanged. Check the date and wording against the linked PDF and the regulator’s current information before relying on a reproduced page.
View the five reproduced guidance pages
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sets out minimum requirements.
Great that composting toilets met those requirements when Portable toilets don't - even if fitted with an aftermarket bracket.
We finally start to see some common sense compliance with the regulated requirements - well done you.