Changes to clause G12 of the New Zealand Building Code, effective May 2026, have prompted a sector-wide review of products used in potable water supplies. At its core, clause G12 is about ensuring water systems in buildings are safe, adequate, and protected from contamination. 
The updated requirements focus on two key areas: lead content and dezincification resistance in copper alloy components. These requirements impact the plumbing and electrical sector, placing a stronger focus on the materials used in fittings, valves, water heaters, and associated components.
The changes bring New Zealand into closer alignment with standards recognised in Australia and North America: NSF/ANSI/CAN 372 provides an established method for assessing lead content in drinking water system components, while AS 2345:2006 provides the framework for confirming dezincification resistance in copper alloy products used in water supply applications.
The first change limits the maximum lead content for products that contain copper alloy. Where products are used in potable water systems intended for human consumption, the weighted average lead content must be no more than 0.25%. By this definition, less than (or equal to) 0.25% weighted average lead content is considered “lead-free”. Lead-free verification must be supported by testing from an IANZ (or equivalent) accredited testing facility, in accordance with NSF/ANSI/CAN 372.
The second requirement applies to dezincification resistance. Copper-base alloy components that are in contact with water and subject to hydrostatic pressure must be dezincification resistant. Dezincification is a form of corrosion whereby zinc leaches from brass alloy materials. To pass this corrosion testing, forgings and cast materials must have an average depth of dezincification of less than 100μm, in compliance with AS 2345:2006.
While the lead-free requirement is intended to reduce potential lead exposure from products used in potable water systems, the dezincification resistance requirement adds a separate check on copper alloy performance in service.
For Smiths, the regulation update prompted an assessment of our water heating element range; this resulted in modifications to the material of the brass boss (the threaded component of the element that houses the terminals) we also reviewed our supporting compliance documentation.
H59 brass has traditionally been used as a boss material in water heating elements. However, with the recent Building Code amendments, it is no longer suitable for the outlined potable water applications.
In response, Smiths exchanged the traditional boss material of affected water heating elements for ECO brass – carefully selected to meet the new lead-free and dezincification resistance requirements. Product codes and descriptions have been altered accordingly: existing codes are now suffixed with LF to indicate Lead-Free.
The affected products have been tested against the applicable standards, with Supplier Declarations of Conformity prepared to support compliance. These SDoCs are backed by accredited test reports which include authorised results for lead content in accordance with NSF/ANSI/CAN 372, and dezincification resistance pursuant to AS 2345:2006.
The Smiths brass boss element range now aligns entirely with the revised expectations for potable water plumbing products.
For the affected water heating element range, the mandatory material changes have been made; ECO brass has been adopted, and corresponding Supplier Declarations of Conformity are available to support compliance with G12/AS1. This gives the industry a clear, documented position from Smiths, as reassurance that our products meet the Acceptable Solution requirements.
It is worth noting that not every water heating element construction is affected in the same way. Water heating elements from the Smiths Titanium Pro range maintain compliance because their construction does not rely on a brass boss. Instead, the SLWT range boasts a titanium sheath and 316 stainless steel boss. The existing material construction already aligns with the intent of the updated regulations.
Across the sector, these Building Code changes raise the baseline for products used in potable water systems. They give manufacturers, importers, wholesalers, and installers clearer expectations, while supporting greater consistency across products used in New Zealand water supply systems.
Smiths have supplied the electrical sector for many years, and water heating remains an important part of that work. Our role is to ensure the products we supply are fit for purpose, properly documented, and aligned with the current requirements of the New Zealand market. Smiths are proudly demonstrating our commitment to upholding the standards of the industry and will continue to do so in years to come.
