Do I Need a Licensed Plumber to Replace a Hot Water Cylinder in NZ?

What the Law Says in NZ

The Plumbers, Gasfitters and Drainlayers Act 2006 requires that all sanitary plumbing work — including hot water cylinder installation and replacement — is performed by a licensed plumber or under the direct supervision of one. The work must be signed off with a Certificate of Compliance (CoC). Without a CoC, the work is illegal and your home insurance may not cover related claims.

Why Does Licensing Matter for Hot Water Cylinders?

• Safety: A correctly installed pressure relief valve, expansion valve, and temperature settings are critical safety items. Incorrect installation can cause dangerous over-pressure situations.
• Warranty: Cylinder manufacturers require licensed installation for the product warranty to be valid.
• Insurance: Home insurance claims for water damage from an unlicensed installation will likely be declined.
• Sale of property: Unlicensed work must be disclosed and remediated when selling your home.

What Is a Master Plumber?

A Master Plumber is a licensed plumber who is also a member of Master Plumbers NZ — a trade association that requires members to meet additional standards around insurance, workmanship guarantees, and continuing education. Choosing a Master Plumber gives you an additional layer of protection beyond the licensing requirement.