New plumbing product standards take effect May 2026

As previously reported in Under Construction, from 2 May 2026, certain copper alloy plumbing products must meet new “lead-free” and corrosion-resistance standards under updates to the Building Code Acceptable Solution G12/AS1 

MBIE first proposed the changes to G12/AS1 during its 2022 Building Code update consultation. After strong support from the sector during consultation, MBIE confirmed the new requirements would proceed. 

A transition period was introduced and subsequently extended to give suppliers, builders and plumbers more time to adapt. The new rules will be mandatory for all applicable plumbing products from 2 May 2026. 

What’s changing 

The revised G12/AS1 introduces two key product standards: 

• Lead content limit: Certain plumbing products made from copper alloys and intended for use in contact with potable water must be “lead-free”, defined as having a weighted average lead content of no more than 0.25%. 

• Dezincification resistance: Copper alloy water supply system components that are in contact with water and subject to hydrostatic pressure must be made from materials that are resistant to dezincification, a corrosion process where zinc is leached from the alloy, leaving behind a porous copper residue. 

The “lead-free” requirement does not apply to products not intended to supply water for human consumption, including showers, toilets, and non-potable systems. 

Components that are not subject to hydrostatic pressure, including open-ended items like shower heads and bath spouts, are exempt the dezincification requirement. 

Why it’s changing  

The current lead limit of 4.5% will be lowered to 0.25% to minimise the risk of lead leaching into drinking water, which can pose long-term public health risks.   

Dezincification resistance is being introduced to prevent corrosion in high-zinc copper alloys. Without it, fittings may weaken over time, leading to leaks or increased zinc levels in drinking water, also a potential health concern. 

When the new rules apply 

The updated requirements take effect from 2 May 2026. Building work consented or applied for on or before 1 May 2026 can continue to use the previous version of G12/AS1. From 2 May 2026, all new consent applications must follow the updated provisions. 

For consent-exempt work under Schedule 1 of the Building Act 2004, installers must comply with the Acceptable Solution in effect at the time of installation. 

Identifying compliant products 

MBIE advises checking product compliance well ahead of the 2 May 2026 deadline. For lead-free status, look for supplier-provided building product information, recognised international certification marks (such as the Australian Lead Free WaterMark), or test reports from an IANZ-accredited laboratory. 

For dezincification resistance, look again at supplier-provided building product information and test reports, as well as copper alloy components marked with the letters ‘DR’.