Water Efficiency Labelling (WELS) & AS/NZS 6400 — What Plumbers Need to Know

By Shelton Allenberg · QBCC Licensed Plumber & Gas Fitter (Lic. 15371578) · Gold Coast, QLD · Published 2026-07-29

Every tap, showerhead, toilet, and urinal you install in Australia must comply with the Water Efficiency Labelling and Standards (WELS) scheme. Established in 2005 under the Water Efficiency Labelling and Standards Act 2005 (Cth), WELS is Australia's national framework for reducing urban water demand by ensuring plumbing fixtures meet minimum efficiency standards. As a licensed plumber, you are legally classified as a "supplier" under the Act — meaning you carry direct compliance obligations every time you supply and install a regulated product.

This guide covers everything you need to know: the minimum star ratings under AS/NZS 6400:2016, your legal obligations, the dual compliance requirement with WaterMark, state-specific rules for Queensland and New South Wales, penalties for non-compliance, and the most common mistakes plumbers make on site.

What Is the WELS Scheme?

The WELS scheme is administered by the Department of Climate Change, Energy, the Environment and Water (DCCEEW). It requires all regulated water-using products to be registered on the national WELS database, tested to AS/NZS 6400:2016 (as amended June 2022), and labelled with a star rating before they can be legally supplied in Australia. The scheme covers showers, taps (excluding bath taps), flow controllers, toilets, urinals, dishwashers, washing machines, and combination washer-dryers.

According to DCCEEW estimates, water-efficient products save Australians approximately $1.6 billion annually in reduced utility bills — with 65% of those savings coming from reduced energy costs for water heating and 35% from lower water bills. For a four-person household, that translates to roughly $170 per year in savings.

Minimum Star Ratings — The Numbers You Must Know

Since 21 July 2023, products below the minimum star rating can no longer be legally sold or installed in Australia. Sub-minimum registrations expired on that date under the WELS Regulator's transition advice (June 2022). The current minimum ratings under AS/NZS 6400:2016 Amendment 1:2022 are:

Important note on showerheads: The maximum achievable WELS rating for showerheads is currently 3 stars. Unlike taps (which go up to 6 stars), there is no 4-star, 5-star, or 6-star category for showerheads under the current edition of AS/NZS 6400. This means every compliant showerhead on the market is already at the minimum — there is no "better than minimum" option for showers.

Higher Star Ratings — What They Mean for Taps

While the minimum for taps is 3 stars, higher-rated taps deliver significant water savings:

When specifying higher-rated taps, be aware that lower flow rates affect hot water delivery time. A 5-star tap at 4.5 L/min delivers roughly half the volume of a 3-star tap at 9 L/min. This means the hot water system needs to be closer to the outlet, or the customer will wait longer for hot water to arrive. Discuss this trade-off with the homeowner or builder before installation.

Your Legal Obligations as a Plumber

Under Sections 33 and 34 of the WELS Act 2005, you are considered a "supplier" if you supply WELS-regulated products as part of installation or repair work. This means you must:

1. Only supply registered products — Before purchasing fixtures for a job, verify the product is registered on the WELS database at waterrating.gov.au. An unregistered product cannot be legally supplied, regardless of its quality or brand reputation.
2. Ensure correct labelling — Every regulated product you supply must carry its WELS star rating label. If you're supplying products in a display home or as part of an inclusions list, the labels must be visible to prospective purchasers.
3. Not modify flow-control devices — You must not remove, modify, or bypass aerators, flow restrictors, or flush mechanisms after installation. The product must perform at its registered flow rate in service. Removing an aerator to "improve pressure" for a customer makes the installation non-compliant.
4. Verify WaterMark certification — Under NCC 2025 Volume Three (Plumbing Code of Australia), every plumbing fixture must hold WaterMark certification before it can be registered under WELS. A product with WaterMark but no WELS registration is still illegal to supply.

WaterMark vs WELS — Understanding Dual Compliance

One of the most common areas of confusion is the relationship between WaterMark and WELS. They are separate schemes with different purposes:

The key takeaway: A product needs BOTH certifications. WaterMark alone is not enough — the product must also be WELS-registered. Conversely, a WELS registration cannot exist without WaterMark certification first. Always check both before ordering fixtures for a job. This dual check adds approximately 10–15 minutes per product to your specification process but prevents costly rework and potential fines.

State-Specific Requirements

Queensland — QDC 4.1 (Sustainable Buildings)

Queensland Development Code Mandatory Part 4.1 has required 3-star minimum WELS ratings for all regulated fixtures in new Class 1 buildings since 2009. Key points for QLD plumbers:

• The committed star rating must be specified at the development approval stage — you cannot change fixtures to a lower-rated product during construction without amending the approval.
• QDC 4.1 applies to new houses, townhouses, and units. It does not apply to renovations unless the work triggers a new building approval.
• The certifier will check that installed products match the approved star ratings at the final inspection. Mismatches result in a failed inspection and rework.

New South Wales — BASIX (Building Sustainability Index)

In NSW, the BASIX scheme requires a committed WELS star rating for every fixture at the development application stage. The BASIX certificate specifies exact star ratings, and the certifier verifies compliance at the final inspection. Key considerations:

• BASIX often requires higher than minimum star ratings to achieve the water reduction target — particularly for multi-unit developments where cumulative savings are needed to pass.
• If you substitute a fixture with a different model, it must have an equal or higher star rating than what was committed on the BASIX certificate.
• BASIX water targets were tightened in the 2022 update. Many projects now need 4-star or 5-star taps to achieve compliance, especially in Sydney metro areas.

Victoria, South Australia, and Other States

All states and territories enforce the WELS Act as a national scheme. While QLD and NSW have additional state-level instruments (QDC 4.1 and BASIX), the baseline WELS requirements — registration, labelling, and minimum star ratings — apply uniformly across Australia. Check with your state's building regulator for any additional local requirements.

Common Compliance Mistakes

Based on WELS compliance inspections and industry feedback, these are the most frequent mistakes plumbers make:

1. Installing Unregistered Products

Cheap imported taps purchased from online marketplaces often lack WELS registration. The product might look identical to a registered model but have a different model number or manufacturer. Always verify the exact model number on the WELS database — not just the brand name.

2. Removing or Modifying Aerators

When a customer complains about "low pressure" from a new tap, some plumbers remove the aerator or flow restrictor. This immediately makes the installation non-compliant. The correct response is to check the supply pressure (should be 150–500 kPa for most fixtures) and address any upstream restrictions rather than defeating the efficiency device.

3. Assuming WaterMark = WELS Compliant

A product can have valid WaterMark certification but no WELS registration. This is common with specialist or newly imported products. WaterMark proves the product is safe; WELS proves it's water-efficient. You need both.

4. Not Checking Registration Expiry

WELS registrations have expiry dates. A product that was registered 5 years ago may have an expired registration. The WELS database shows current registration status — always check before purchasing stock, especially from clearance sales or old warehouse inventory.

5. Ignoring Labelling on Inclusions Boards

If you're supplying fixtures for a display home or spec build, the WELS star rating labels must be displayed on an inclusions board near the unit entrance. Many plumbers assume this is the builder's responsibility, but if you supplied the product, you share the obligation.

6. Substituting Lower-Rated Products Without Approval

On BASIX or QDC 4.1 projects, substituting a 4-star tap with a 3-star tap (even though 3-star meets the national minimum) can fail the final inspection if the approval specified 4-star. Always confirm with the builder or certifier before making substitutions.

Penalties for Non-Compliance

The WELS Act provides for escalating enforcement responses:

• Infringement notices — issued on-the-spot by WELS inspectors for minor breaches
• Civil penalties — up to $13,320 per product for individuals and $66,600 per product for corporations
• Criminal prosecution — for serious or repeated offences

Note that penalties apply per product. If you install 10 unregistered taps in a multi-unit development, that's potentially 10 separate contraventions. WELS inspectors will generally attempt to resolve non-compliance cooperatively before escalating to enforcement action, but ignorance of the requirements is not a defence.

Practical Workflow: Checking WELS Compliance Before Installation

Follow this workflow for every job involving regulated fixtures:

1. Identify the product model number — Check the packaging, product label, or supplier invoice for the exact model number (not just the brand or series name).
2. Search the WELS database — Go to waterrating.gov.au and search by model number or WELS registration number. Confirm the registration is current (not expired).
3. Verify the star rating meets project requirements — For standard residential work, 3-star minimum is sufficient. For BASIX or QDC 4.1 projects, check the approved star rating on the development approval documents.
4. Confirm WaterMark certification — Check the product carries a valid WaterMark licence number. This is usually stamped on the product body or printed on the packaging.
5. Install without modification — Install the product as supplied. Do not remove aerators, flow restrictors, or modify flush mechanisms.
6. Retain documentation — Keep a record of the WELS registration number and star rating for each product installed. This protects you if compliance is questioned later.

Frequently Asked Questions

Do bath taps need to be WELS registered?

No. Taps installed exclusively over a bath are exempt from WELS regulation under AS/NZS 6400:2016. However, if the tap serves both a bath and a basin (e.g., a wall-mounted tap that swings between the two), it must be registered. Bath/shower mixer taps with a diverter are regulated for the shower component.

What about replacement like-for-like work?

If you're replacing a fixture with the same model, the replacement must still be WELS-registered at the time of supply. You cannot install old stock of a product whose registration has expired, even if the original installation was compliant when first fitted. The obligation applies at the point of supply, not the point of original manufacture.

Can I install a product I didn't supply?

If the homeowner purchases their own fixtures and you only provide labour, you are not the "supplier" under the WELS Act and the registration/labelling obligation falls on whoever sold the product to the homeowner. However, you should still verify WaterMark certification before installation, as NCC Volume Three requires all installed plumbing products to be WaterMark-certified regardless of who supplied them.

What if a product is registered but I can't find the label?

If the product is confirmed as registered on the WELS database but the physical label is missing (e.g., damaged in transit), you can still install it. The labelling obligation primarily applies at the point of display or offer for supply. However, for display homes or inclusions boards, the label must be visible to prospective purchasers.

Does WELS apply to commercial buildings?

Yes. WELS applies to all regulated products supplied in Australia, regardless of building classification. Commercial buildings (Class 2–9) must use WELS-registered fixtures. Additionally, Green Star and NABERS Water ratings often require higher star ratings than the minimum, so commercial projects typically specify 4-star or 5-star fixtures.

How do I check if a product's WELS registration is still current?

Search the product on the WELS database at waterrating.gov.au. The database shows the registration status (current or expired), the registration number, star rating, and expiry date. If the registration has expired, the product cannot be legally supplied — even if you have existing stock.

Are flow controllers a separate WELS category?

Yes. Flow controllers (devices that restrict flow rate independently of the tap or showerhead) are a separate WELS-regulated product category. They must be independently registered and rated. You cannot use an unregistered flow controller to bring a non-compliant tap into compliance — both the tap and any flow controller must be individually registered.

Key References

• Water Efficiency Labelling and Standards Act 2005 (Cth) — Sections 33–34 (supply obligations), Section 76 (scheme review)
• AS/NZS 6400:2016 (Amendment 1, June 2022) — Water efficient products — Rating and labelling
• NCC 2025 Volume Three — Plumbing Code of Australia (WaterMark requirements)
• Queensland Development Code MP 4.1 — Sustainable Buildings (3-star minimum since 2009)
• BASIX — NSW Building Sustainability Index (committed star ratings)
• WELS Regulator Transition Advice (June 2022) — Sub-minimum registration expiry

This article is general guidance only and does not constitute legal advice. Always verify compliance requirements with your state's technical regulator and the current edition of AS/NZS 6400 before commencing work. Information current as of July 2026. QBCC Lic. 15371578.