Singapore legislation
Regulation 43
of Road Traffic (Motor Vehicles, Construction and Use) Rules
Regulation 43
Closets, urinals, lavatory basins and sinks
No motor vehicle or trailer shall be equipped with any closet, urinal, lavatory basin or sink, unless the following requirements are complied with:
no vehicle shall be equipped with a closet or urinal the contents of which can be discharged directly on to a road and every closet pan or urinal pan shall empty into a tank carried by the vehicle such tank —
being efficiently ventilated by means of a pipe, the outlet of which is outside the vehicle; and
shall contain non-inflammable and non-irritant chemicals of such character and in such quantity as to form at all times an efficient deodorant and germicide in respect of the contents of the tank; and
no lavatory basin or sink shall drain into any closet or urinal or into a tank into which a closet or urinal empties.