This report explores self-certification models in construction industry trades. In particular, the key features of self-certification in regulated occupations and critical factors that make it successful. Findings demonstrate that the current regulatory system for plumbing and drain laying is not working well. 

Key recommendations:

1. Note that irrespective of the regulatory approach, improvements to the system are needed to ensure that quality outcomes are achieved in an efficient manner.
2. Determine a risk-based categorisation of plumbing and drain laying installations based on factors including building type, whether the installation is a standardised design and the level of risk to public health.
3. Investigate further the consistency and quality of training of plumbers and drain layers, including ongoing training, to determine whether training levels support dependable self-certification.
4. Use the findings of this report to establish the record-keeping that is necessary to support risk-based auditing of self-certification of construction trades.
5. Investigate the process by which occupational regulatory bodies address work quality issues and the extent to which this needs to be strengthened to support dependable self-certification.
6. Investigate the extent to which consumers have access to remedies for poor quality work and whether this needs to be strengthened or mandated for successful self-certification.