WaterMark is the mandatory Australian plumbing product certification. Every legitimate whole-home water filter system must carry a WaterMark licence. The licence number is publicly searchable on the ABCB register at abcb.gov.au — you can verify it yourself in 30 seconds.
Red flag: If they can't give you a specific licence number, or say "our components are WaterMark certified" (rather than the system), this is a compliance concern. Installed plumbing products without WaterMark certification may fail a building inspection.
Good answer: They immediately provide a licence number (e.g. "Licence #23448") and optionally tell you how to look it up. Write it down and check it when you get home.
NSF certification standards are specific: NSF 42 = chlorine/taste/odour, NSF 53 = heavy metals and health contaminants, NSF 58 = reverse osmosis, NSF 401 = emerging contaminants including pharmaceuticals. Each requires independent lab testing. The claim "NSF certified" without a standard number is meaningless.
Red flag: "NSF certified" without specifying which standard. "NSF-compliant components" (vs the system itself). Unable to produce a test report or direct you to the NSF database listing.
Good answer: Specifies exact standards (e.g. "NSF 42 and 53 on the full system") and can point you to the NSF database at nsf.org or provide a test report.
Many suppliers make contaminant removal claims without any supporting test data. "Removes 99% of PFAS" is a very different claim depending on whether it comes from independent lab testing or the manufacturer's marketing material.
Red flag: No data sheet or test report available. Claims like "designed to remove" or "capable of removing" rather than tested reduction percentages. Referencing competitor's test data instead of their own.
Good answer: Can provide a performance data sheet with tested reduction percentages from an independent lab (SGS, Intertek, NSF). Reduction percentage is stated per contaminant.
PFAS (per- and polyfluoroalkyl substances) are an emerging concern in Australian water supplies, particularly in areas near military bases, airports, and industrial sites. Standard activated carbon filters have limited PFAS removal capability. Specific media (Filtrasorb, PFAS-rated carbon) and reverse osmosis are required for meaningful reduction.
Good answer: Can confirm whether their specific media is rated for PFAS, and provide a tested reduction percentage. Not all systems remove PFAS — it's okay if they say "this system isn't designed for PFAS, here's what it does address."
In Australia, installing a water filter that connects to household plumbing must be performed by a licensed plumber. Unlicensed installation can void home insurance, create compliance issues on property sale, and result in WaterMark certification being irrelevant (the installation itself is non-compliant).
Red flag: Hesitation to confirm licensed plumber. "You can install it yourself." They offer to connect to your plumbing without being a licensed plumber.
Good answer: Confirms all installs are by licensed plumbers, and can provide the plumber's licence number on request or on the invoice.
Standard filter sizes (10" × 2.5", 10" × 4.5", 20" × 4.5" Big Blue) are available from dozens of suppliers — Bunnings, Reece, online retailers, and competitor installers. Proprietary sizes (like a custom 15" cartridge) mean you must buy from the installing company forever at whatever price they charge.
Red flag: They can't give you the cartridge dimensions. They say "our proprietary filter." They confirm you must buy replacements through them. Any non-standard sizing (not 10" or 20" standard).
Good answer: States exact dimensions (e.g. "20 inch by 4.5 inch Big Blue") and confirms aftermarket replacements are available. Standard housings from multiple brands fit.
A system that costs $1,500 with $50/year filter replacements is very different from one that costs $2,000 with $400/year in proprietary replacements. The 5-year total cost of ownership can vary by thousands of dollars based on this alone.
Red flag: Unable to state an annual filter cost. Only available "through our service team." Filter costs not included in their quote. Subscription model where you can't opt out.
Good answer: Provides a specific annual replacement cost and can name third-party suppliers where cartridges are available (Bunnings, Reece, Amazon, etc.).
Change intervals vary from 6 months to 3 years depending on the system, your water quality, and household size. "Change every 12 months" on poor-quality bore water might actually mean "change every 6 months." Understand the real-world expectation for your situation.
Good answer: States a specific interval, explains what affects it (sediment load, usage), and mentions how you'll know when it's time — filter change indicator, water pressure drop, or calendar reminder.
Some suppliers bundle installation with mandatory service contracts. The annual service fee may be reasonable at sign-up but can increase. Understand exactly what you're committing to and for how long before signing.
Red flag: Mandatory annual service visit. Multi-year service contract buried in the fine print. Warranty voided if you use another technician. Exit fees or minimum term.
Good answer: Service is optional, not mandatory. Warranty is not contingent on using their service team. Annual servicing cost is stated clearly and is not required to maintain compliance.
Most whole-home filter cartridges can be swapped in under 5 minutes with no tools. Some suppliers obscure this to maintain service revenue. DIY-replaceable cartridges dramatically reduce your ongoing costs.
Good answer: "Yes, you just twist and swap — takes about 2 minutes." Shows you the housing and how it opens. Offers to walk you through it on installation day.
Some quotes show the system cost only, then add installation labour, fittings, and bypass valves as separate line items. Always ask for the all-in number so you can compare like-for-like between suppliers.
Good answer: A single "total installed" figure that includes system, all fittings, labour, and bypass valve. No surprise additions after installation.
Asking for a 5-year TCO forces the supplier to factor in filter replacement costs, which dramatically changes the comparison between a $1,200 standard system and a $2,800 proprietary-filter system. Run the numbers yourself and compare.
Good answer: They calculate this with you on the spot: system + install + (annual filter cost × 5). You can then compare this number across multiple quotes.
For systems with proprietary servicing, call-out fees can add hundreds of dollars to the annual cost — particularly if the service is triggered by their subscription model rather than actual need.
Red flag: High call-out fees ($150+) for a simple filter change you could do yourself. Mandatory annual visit regardless of filter condition. No transparency on what triggers a service charge.
Good answer: Service is optional and clearly priced. Call-out fee is stated upfront. They show you how to do basic filter changes yourself to avoid needing service calls.
Some companies quote verbally and adjust on installation day once the plumber is on-site. Get everything in writing with a fixed price before booking.
Good answer: They provide a written fixed-price quote valid for 30+ days. The quoted price doesn't change based on access conditions at your home (unless genuinely unusual).
You are covered by Australian Consumer Law regardless of what their contract says — but understanding their process avoids a dispute. Reputable suppliers stand behind their product with reasonable return terms.
Good answer: Offers a satisfaction period (7–30 days), or at minimum explains the warranty and what fault rectification looks like. Doesn't become evasive when asked.
Whole-home filter systems are typically installed on the main water line at the point of entry — usually near your water meter. The location affects access for filter changes, visual appearance, and pipe runs. Confirm placement before they start cutting pipes.
Good answer: Shows you the proposed location during the consultation, explains why they've chosen it, and confirms you're happy before proceeding.
Most whole-home installs take 30–90 minutes with a brief water shut-off. Knowing this in advance helps you plan — particularly important for households with young children or if you work from home.
Good answer: Gives a realistic time estimate, specifies how long water will be off (usually 15–30 minutes), and mentions any other household disruption.
Warranty terms often differ between the filter media (typically 12 months), the housing/vessel (5–10 years), and the installation workmanship (sometimes very limited). Understand each separately.
Good answer: Breaks down warranty by component — e.g. "5 years on housing, 12 months on filter media, 12 months on installation workmanship." Provides this in writing.
In most Australian states, plumbing work must be accompanied by a Certificate of Compliance (or equivalent) issued by the licensed plumber. This document protects you during home inspections and insurance claims. Requirements vary by state — ask regardless.
Red flag: Unsure what a Certificate of Compliance is. Confirms no certificate will be provided. Says "it's not required for water filters" — this varies by state and installation complexity.
Good answer: Confirms they provide a Certificate of Compliance or equivalent documentation, and can explain what your state requires.
A leaking connection on a main water line can cause significant water damage. Knowing the after-install support process — who to call, how fast they respond — tells you how seriously they take post-sale responsibility.
Good answer: Provides a direct contact number for post-install issues. States a response time (e.g. next business day, or emergency same day for leaks). Explains what's covered under installation warranty vs normal wear.
Water quality varies significantly by postcode, suburb, and even street. A supplier who recommends the same system to every customer hasn't done their job. State water authorities publish annual water quality reports — any prepared supplier should have consulted yours before recommending a product.
Red flag: Recommends a specific system without asking where you live, what your water source is, or what contaminants concern you. Offers the same "best seller" to every customer.
Good answer: References your local water utility's quality report, or offers a water test. Explains how their recommendation is specific to your water profile.
Standard whole-home carbon filters are designed for treated town water. Bore water often contains iron, manganese, sulphur, and hardness that require specialised treatment. Tank water may contain bacteria requiring UV sterilisation. A standard filter on bore water will clog rapidly and may not address the actual contaminants.
Good answer: Specifically addresses your water source and explains how their system (or a modified recommendation) handles its characteristics. If they're not equipped for your water type, they say so.
Flow rate is measured in litres per minute (L/min). Most whole-home systems deliver 15–48 L/min. For households with 3+ bathrooms, multiple simultaneous showers will expose a low-flow system. The general rule is 10–15 L/min per bathroom.
Good answer: States a specific L/min figure, relates it to your household size (number of bathrooms, occupants), and confirms it's appropriate. Notes if the figure is self-reported vs independently tested.
Have your list of concerns ready before the consultation — chlorine taste, heavy metals, PFAS, fluoride retention, bacteria. Make the supplier address each one specifically with reference to tested reduction data, not just a claim the system "handles it."
Good answer: Goes through your list item by item. Honest about what the system doesn't address. Provides data sheet with tested reduction percentages for each contaminant.
All whole-home filters create some pressure drop — typically 10–20 kPa. For homes with borderline water pressure, this can be noticeable. Ask specifically if they've assessed your inlet pressure and whether the system is appropriate.
Good answer: Checks your current inlet pressure (or asks about it), states the pressure drop of their system, and confirms it's within acceptable range for your home's supply.
A company that's been operating for 10+ years is more likely to still be around when you need parts. A reseller who drops a brand means you may not be able to get cartridges for your specific housing. Understanding the supply chain matters for long-term ownership.
Good answer: Honest about how long they've operated and their relationship to the brand — manufacturer, exclusive distributor, or open reseller. Explains how cartridge supply is maintained long-term.
Legitimate businesses have Google reviews. A supplier with very few reviews (under 20), a suspiciously uniform set of 5-star reviews, or who discourages you from looking is a concern. Check independently at Google Maps or ProductReview.com.au.
Red flag: Fewer than 20 Google reviews. All reviews are 5-star with similar wording. They discourage you from looking online. No reviews mentioning the installation experience specifically.
Good answer: Encourages you to check reviews, provides their business name and location for searching, and their reviews mention specific installation details that match real experience.
A WaterMark-certified, professionally installed system is generally viewed as a property improvement by buyers. But a proprietary-format system with ongoing service obligations can complicate a sale, particularly if the buyer doesn't want to commit to the supplier relationship.
Good answer: Confirms the system adds value as a certified plumbing improvement, can be removed and reinstalled if needed, and doesn't carry transferable contractual obligations that would concern a buyer.