When is minor plumbing work considered to be major plumbing work for the purposes of self-certification?
• Minor plumbing work that is carried out as part of major plumbing work is considered to be major plumbing work for the purposes of self-certification. This means that any work that is minor, such as replacing existing water supply plumbing, that is associated with major plumbing work being carried out, such as the replacement of a hot water unit, can be certified on the same certificate of compliance as the major work. Therefore, if the existing water supply pipework between the isolating valve and a hot water unit is replaced at the same time as the hot water unit, the certificate of compliance used to certify the hot water unit replacement can also be used to certify the replacement of the water supply pipework.
