Sewage cannot be dumped in sensitive areas, such as inland waters and around special environments like coral reefs. In Queensland a boat must be more than five kilometres from shore before boat owners can empty their boats’ sewage. If a boat does have a fixed toilet on board, the toilet must have a built in machine that mashes all solid material going into the toilet.
Even if there is a sewage treatment system onboard, the places where treated sewage can be discharged into the water will be different depending on the grade of treatment. At the highest level of treatment (Grade A), there are no restrictions. For Grade B, a boat must be at least 700 m from sensitive areas. For Grade C, a boat must be at least 1km from sensitive areas.