About WaterWatch Australia
WaterWatch Australia is built for everyday residents — not for water utilities or regulators. Our goal is to make it easy to see what actually comes out of your tap, how that compares to neighbouring suburbs, and how it stacks up against the independent national drinking water guidelines. You can browse every locality on the interactive map or explore the full Western Australia overview.
Where the numbers come from
The data is published each year by the water supplier (currently the Water Corporation of WA). They have an obvious commercial interest in showing that water meets the rules, so we don't take their pass/fail summary at face value.
Instead, every reading is compared against the Australian Drinking Water Guidelines (ADWG) set by the National Health and Medical Research Council — a separate, independent body. The ADWG values are the real health-based benchmark, and they're the same right across Australia.
Why we don't show three numbers
The official reports give a minimum, mean and maximum for each parameter. That's useful for engineers but confusing for residents. We simplify it to:
- Typical reading — the mean of the year's samples. This is what your water usually looks like.
- Peak — the single highest sample. For contaminants, the peak matters more than the average.
- Range— for pH and fluoride, which have a target band rather than a maximum, we show the year's range against that target.
How we describe results
Each parameter card shows where your reading falls compared to the ADWG limit:
- Well within guideline — at most half of the limit.
- Within guideline — between half and 80% of the limit.
- Near guideline — between 80 and 100% of the limit. Usually fine but worth watching.
- Above guideline — exceeds the ADWG limit at some point during the reporting year.
- Not enough data — for some parameters (metals, pesticides, hydrocarbons) the supplier publishes a yes/no compliance summary instead of concentrations.
Comparing to other places
For each parameter we also calculate the average typical reading across your region and across the whole state, so you can see quickly whether your area is unusually hard, salty or chlorinated — or just like everywhere else nearby.
Health vs aesthetic
Health parameters (E. coli, fluoride, lead, trihalomethanes…) are about whether the water is safe to drink. Aesthetic parameters (hardness, salts, iron, pH…) are about taste, smell, appearance and wear on your kettle and plumbing. Going over an aesthetic limit isn't a health risk — it just means the water may not be pleasant.