WaterMark Certification Explained
WaterMark is the Australian certification scheme for plumbing products that connect to mains water supply. It is not optional — Australian state plumbing regulations require WaterMark certification on every product fitted to mains-pressure water supply. That includes filters, taps, fittings, valves, and any product where a failure could contaminate the supply or damage downstream plumbing.
The scheme exists because failure modes on mains-pressure plumbing are expensive. A tap that splits, a filter housing that cracks, a backflow prevention valve that does not — all of those cause property damage, water contamination, and council issues. WaterMark certification means the product has been tested against the relevant Australian Standards (the AS/NZS 3500 series for plumbing, AS/NZS 4020 for products in contact with drinking water, plus product-specific standards) and is approved for mains-pressure installation in Australia.
Who issues the certification
Three Joint Accreditation System of Australia and New Zealand (JAS-ANZ) accredited certifiers issue WaterMark licences:
- IAPMO Oceana
- SAI Global
- Global-Mark
A certified product carries a WaterMark licence number (typically formatted WMK-XXXXX) issued by one of those bodies. The licence covers a specific product specification — substituting parts or modifying the product invalidates the certification.
Where it applies
WaterMark applies to anything plumbed into mains water supply in Australia. The most common categories on this site:
- Whole-house water filters — they sit on the mains, certification required.
- Under-sink filters connected to mains-pressure cold-water lines — certification required for the housing and any included fittings.
- Kitchen and bathroom taps — every mains-pressure tap, mixer, and outlet.
- Toilet cisterns and pans — mains-fed, certification required.
- Backflow prevention valves and pressure-reducing valves — certification required.
WaterMark does not apply to:
- Bench-top filters that connect to an existing tap with a removable diverter — they are not plumbed into the mains.
- Caravan, RV, and off-grid systems that run on tank or pump pressure rather than mains.
- Rainwater-only systems including UV sterilisers fed from a tank.
- Cartridges themselves — the cartridge inside a certified housing is not separately certified.
Non-certified products on this site are clearly labelled "Not WaterMark certified — for off-mains use only". They are perfectly legal for the off-mains applications above, and they are often cheaper than the certified equivalents because the certification process itself adds cost.
Verifying a licence
Every certified product on this site lists its WaterMark licence number on the product page under Specifications. The licence number lets you (or a council inspector) verify the certification is current via the certifier's online register. We update licence numbers when certificates renew.
If a product is plumbed into mains supply and you cannot find a licence number on the product page or the physical product, treat it as non-certified — and do not install it on a mains line.
Frequently asked questions
Where do I find the WaterMark licence number for a product?
On the product page under Specifications, every WaterMark-certified product on this site shows its licence number (typically in the format WMK-XXXXX). Non-certified products are flagged 'Not WaterMark certified — for off-mains use only'. If you cannot see a licence number on a mains-pressure product page, the product is not certified.
Is WaterMark the same thing as WELS?
No. WaterMark is the certification scheme for plumbing products that physically connect to mains water supply — it confirms the product is safe and meets relevant standards. WELS is the Water Efficiency Labelling Scheme — it rates flow rate and water-saving performance (the star rating you see on taps and showers). A tap can be both WaterMark certified and WELS rated; they cover different things.
What happens if I install a non-certified product on mains water?
The install does not comply with state plumbing regulations. A council inspector can require the product to be replaced, the homeowner is liable for damage caused by failure, and the licensed plumber who did the install can lose their licence. None of this is theoretical — councils do check, especially on new builds and major renovations.
Can I install a non-certified filter on rainwater or off-mains supply?
Yes. WaterMark only applies to products connected to mains water. Rainwater tanks, bore-water supplies, caravan/RV systems, and any installation where the filter is not on a council-supplied mains line are not subject to WaterMark requirements. Non-certified products are clearly labelled on this site for that reason.