When it comes to raising a healthy family, most of us are pretty diligent about reading nutrition labels - checking sugar content, additives, serving sizes. But how often do we look at what's actually coming out of the kitchen tap?
Whether you're in New Zealand or Australia, your local council or water utility tests the municipal supply regularly and publishes the results in a public compliance report. The trouble is, these reports read like they were written for scientists - rows of chemical names, decimal points, and acronyms that don't mean much at a glance.
Once you know what to look for, though, they're actually pretty easy to make sense of. Here's an easy guide to reading your own.
The Core Standard: What Compliant Means
Every water report measures results against an official health standard - the Drinking Water Standards for New Zealand (DWSNZ) or the Australian Drinking Water Guidelines (ADWG), depending on where you live.
The number to look for is called the Maximum Acceptable Value (MAV), sometimes labelled a Health Guideline Value. This is the highest concentration of a substance that can be present in drinking water without posing any risk to health, even over a lifetime of consumption.
Reading the report comes down to one simple comparison: check the "Result" column against the "MAV" column. If the result sits below the MAV, the water passes - simple as that.
In practice, most municipal water comes in well under these limits. A typical compliance report might show results running at a fraction of the allowable ceiling across the board - which is a good sign, not a coincidence. It reflects genuinely rigorous testing and treatment.
Key Terms
1. Water hardness (calcium and magnesium)
Hardness measures the concentration of dissolved minerals — mainly calcium and magnesium - in your water, usually expressed as mg/L (the same thing as g/m³) of calcium carbonate.
- Soft water (under 60 mg/L) is gentle on skin and hair, easy on your plumbing, and won't leave chalky scale on your kettle or shower glass.
- Hard water (over 120 mg/L) carries more minerals but tends to build up on appliances and fixtures over time, and some people find it drying on skin.
Most council reports list this figure clearly - worth a quick check if you've ever wondered why your kettle scales up quickly, or doesn't.
2. PFAS ("forever chemicals")
Per- and polyfluoroalkyl substances (PFAS), including the well-known variants PFOA and PFOS, are synthetic chemicals once widely used in firefighting foam and non-stick coatings. They've earned the nickname "forever chemicals" because they take an extremely long time to break down in the environment.
What to look for: the words "Not Detected" or "< Limit of Detection" next to these entries. Labs measure PFAS in tiny fractions of a gram per cubic metre, so a non-detect result is exactly what you want to see - it means these chemicals simply aren't present in measurable amounts in your supply.
3. Heavy metals (lead, copper, arsenic, cadmium)
Heavy metals can occur naturally in groundwater, or make their way into supply from ageing municipal pipes and household brass fittings.
What to look for: values for lead, arsenic, and cadmium sitting well under their MAV. Lead in particular is worth a glance, since it typically enters water at the point of use - through old pipework or fittings - rather than at the treatment plant.
4. Disinfectants and disinfection by-products (THMs)
To protect against waterborne pathogens as water travels through kilometres of underground pipework, councils treat supply with disinfectants like chlorine or chloramine.
Trihalomethanes (THMs) form when chlorine reacts with naturally occurring organic matter in the raw water. They're measured against an allowable ratio in the report, and while they're kept well within safe limits, they're also the main reason tap water can sometimes have a faint pool-like smell or a slightly sharp aftertaste.
5. Fluoride
Fluoride is present in New Zealand and Australian supplies either naturally or through deliberate community water fluoridation. It's typically managed within a target range of around 0.6–1.0 mg/L.
If you see a result in that range, your council is fluoridating within the intended dose. Some households prefer more control over their fluoride intake for personal reasons, and a fluoride-reduction filter can address that.
Safe vs. Optimal: Why People Still Choose to Filter
Municipal water providers do a good job getting biologically safe water to your property boundary. "Compliant" though, doesn't always mean "optimal" for taste or day-to-day enjoyment.
By the time water travels from the treatment plant, through ageing street mains, and into home plumbing, it can pick up sediment, trace rust, or a lingering chlorine taste -even when every test on the report comes back well within limits. It's also common for people to simply prefer their water without the taste of added disinfectant.
This is really what home filtration is for. Adding a final layer of polish once water reaches your tap, removing sediment, residual chlorine taste, and any lingering odour so your family gets water that's not just safe, but genuinely pleasant to drink.
Ready to Upgrade Your Home's Water?
Whether you're after a simple under-bench filter for the kitchen, a fluoride-reduction system, or something for the whole house, Mountain Fresh has certified filtration solutions ready for you. Take our quick product quiz to find the right system for your tap, or explore the full range today.