Best and Worst Water Quality Suburbs in Australia (2026)

106 suburbs share the top WaterScore of 9.8 out of 10, and 102 of them are in Tasmania, most on Hobart’s eastern shore. At the other end, Horrocks in Western Australia’s Mid West scores 7.5 on salty groundwater, and seven farming towns on SA Water’s Geranium system score 7.9 on 575 mg/L of hardness. Across 8,416 scored suburbs, those are the best and worst water quality suburbs in Australia on the measured data for 2026.

We scored every suburb using readings published by its water utility. Tasmania and the ACT lead the state averages on soft surface water, while groundwater towns in Western Australia’s Mid West and regional South Australia sit at the bottom. This guide lists the highest- and lowest-scoring suburbs, breaks the results down by state, and explains what drives the differences.

Correction, 23 October 2026. An earlier version of this article listed Williamsdale, Flynn, Taylor and Mount Stromlo in the ACT among the ten lowest-scoring suburbs, and put the ACT last among the states. That was our error. We had loaded Icon Water’s 2015-16 report, which gives metals in micrograms per litre, as if the figures were milligrams per litre, and those rows displaced the current 2024-25 results. We had also misread pH values in SA Water and Seqwater files and trihalomethane units in Seqwater’s. With these fixed, every Canberra suburb scores 9.7 and the ACT has the highest state average. The tables below use the corrected data.

Update, 5 November 2026. Western Australian suburbs now carry the 2024-25 readings for their own Water Corporation scheme or Perth locality. Before, each WA region shared one scheme’s readings, which hid towns such as Horrocks, Guilderton and New Norcia. They now hold the three lowest scores, and Jerramungup joins the top group.

How We Scored 8,400 Australian Suburbs

WaterScore rates each suburb from 0 to 10 based on measured water quality parameters reported by its supplying utility. The score factors in readings for hardness, pH, total dissolved solids (TDS), fluoride, chlorine, turbidity, and other parameters where data is available. Each reading is compared against the Australian Drinking Water Guidelines (ADWG) benchmarks.

Of more than 17,500 suburbs in our database, 8,416 have enough utility data to generate a score. The national average is 9.33 out of 10 and the median 9.5, with scores ranging from 7.5 to 9.8. Scores are rounded to one decimal place, and suburbs on the same supply system share the same readings, so many suburbs tie. The tables below group them by supply system for that reason.

Data depth varies. Tasmanian and Canberra suburbs have readings for more than 30 parameters; some regional systems publish fewer than 10. Each suburb page lists every reading behind its score.

Highest-Scoring Suburbs in Australia

106 suburbs share the top score of 9.8. All but four are supplied by TasWater, and 83 of those are in Greater Hobart.

Supply system	Utility	Suburbs at 9.8	Examples	Hardness (mg/L)	TDS (mg/L)
Coal Valley (Greater Hobart)	TasWater	55	Sorell, Midway Point, Dodges Ferry, Richmond	46	83
Clarence (Greater Hobart)	TasWater	28	Howrah, Bellerive, Lindisfarne, Rokeby	46	75
Gladstone	TasWater	7	Gladstone, Musselroe Bay	16	67
Rossarden	TasWater	4	Avoca, Rossarden	46	70
Bracknell, Bronte Park, Maydena, Mole Creek	TasWater	8	Poatina, Bradys Lake, Florentine, Liena	14–37	41–78
Oak Valley	SA Water	2	Oak Valley, Nullarbor	7	25
Yunyarinyi	SA Water	1	Yunyarinyi	21	33
Jerramungup	Water Corporation	1	Jerramungup	12	57

Hobart’s eastern shore and the Coal Valley towns get soft water, about 46 mg/L hardness, with low dissolved solids and every measured parameter well inside its guideline. The two South Australian systems serve remote Aboriginal communities: Oak Valley on the Maralinga Tjarutja lands and Yunyarinyi in the APY Lands, where hardness is just 7 and 21 mg/L. Jerramungup, a Great Southern farming town, gets water with 12 mg/L hardness.

Just below them, every suburb in Canberra scores 9.7, as do Victoria’s best performers, such as Romsey and Monegeetta.

Why Canberra and Hobart Lead

The common thread is soft surface water, treated well and reported in detail.

Canberra’s water comes from the Cotter catchment in Namadgi National Park and from Googong Dam, treated by Icon Water. Its 2024-25 results put hardness at 36 to 37 mg/L, fluoride at 0.8 mg/L and lead below 0.001 mg/L. Icon Water reports more than 30 parameters, so Canberra’s 9.7 rests on a full set of readings. Our Canberra tap water guide has the detail.

Greater Hobart’s eastern shore and Coal Valley systems score 9.8 on hardness around 46 mg/L and TDS under 85 mg/L, with TasWater publishing more than 30 parameters for them.

Victoria remains close behind, with an average of 9.45 and a top score of 9.7. Melbourne draws from closed catchments in the Yarra Ranges and Central Highlands, and hardness across the city typically sits between 8 and 52 mg/L, well within the “soft” band on our water hardness calculator. For a detailed breakdown, visit the Victoria state overview.

Lowest-Scoring Suburbs in Australia

Low scores do not mean unsafe water. In our data, none of these suburbs exceeds a health-based guideline. Their readings break the aesthetic guidelines for dissolved solids (600 mg/L), hardness (200 mg/L), sodium (180 mg/L) and chloride (250 mg/L), which affect taste and scale rather than safety.

Supply system	Utility	Suburbs	Examples	WaterScore	Hardness (mg/L)	Sodium (mg/L)	Chloride (mg/L)
Horrocks	Water Corporation	2	Horrocks, Sandy Gully	7.5	133	399	606
Guilderton	Water Corporation	3	Guilderton, Gabbadah, Caraban	7.8	340	238	423
New Norcia	Water Corporation	5	New Norcia, Mogumber, Gillingarra, Glentromie, Yarawindah	7.8	177	279	492
Geranium	SA Water	8	Wilkawatt, Peake, Parrakie, Moorlands, Jabuk, Netherton, Carcuma, Geranium	7.9–8.0	575	333	488
Naracoorte	SA Water	18	Naracoorte, Wild Dog Valley, Hynam, Lochaber, Kybybolite	8.0–8.1	355	326	458
Padthaway	SA Water	1	Padthaway	8.0	602	360	662
Melrose	SA Water	1	Melrose	8.0	366	415	575

All seven systems draw on groundwater: three Water Corporation schemes in WA’s Mid West and four regional SA Water supplies. As it moves through limestone and other rock, groundwater picks up calcium, magnesium and salts, which is why the South Australian towns are also among the hardest water suburbs in Australia. Horrocks scores lowest on salt rather than hardness: its 1,305 mg/L of dissolved solids is more than twice the 600 mg/L guideline. Padthaway’s 602 mg/L is three times the hardness guideline, and its chloride of 662 mg/L is more than two and a half times the chloride guideline.

Just above them, 11 suburbs on the Raukkan system near Lake Alexandrina score 8.1. That system publishes only nine parameters, so its score rests on thinner data.

What Drives Low Water Quality Scores

Two factors account for most low scores across Australia.

Hard, salty groundwater. Suburbs drawing from groundwater, particularly in regional South Australia and Western Australia’s Mid West, record hardness of 300 to 600 mg/L or dissolved solids near or above 1,000 mg/L, with sodium and chloride well above the aesthetic guidelines. Water like this leaves scale on kettles and hot water systems, reduces soap performance, and can taste salty. It is not a health risk at these levels, but it scores lower on overall quality. Read more about why Adelaide has Australia’s hardest water.

Data gaps. Some suburbs have limited published data. A system reporting nine parameters gives a thinner picture than one reporting more than 30, so compare scores with an eye on the parameter list on each suburb page. We are working to expand data coverage nationally.

Wealth is not one of the factors. When we compared 2,490 suburbs by household income, the richest fifth averaged 9.44 and the poorest fifth 9.42, as our rich vs poor suburbs analysis shows.

Water Quality Rankings by State

State averages smooth out suburb-level variation and show broad regional patterns. The ACT and Tasmania lead, and every state averages above 9.0.

State	Avg WaterScore	Suburbs Scored	Lowest	Highest
ACT	9.70	169	9.7	9.7
TAS	9.64	797	9.0	9.8
NSW	9.54	1,512	9.5	9.7
VIC	9.45	731	8.9	9.7
NT	9.35	378	8.6	9.6
QLD	9.29	928	9.0	9.5
SA	9.25	2,084	7.9	9.8
WA	9.05	1,817	7.5	9.8

The ACT and Tasmania lead on soft, low-mineral surface water. South Australia and Western Australia span the widest ranges. SA runs from 9.8 in remote communities to 7.9 in groundwater towns, with metro Adelaide (87 to 138 mg/L hardness) in between. WA runs from 9.8 at Jerramungup to 7.5 at Horrocks.

Western Australia sits last, held down by salty, hard groundwater in Mid West and Wheatbelt towns. 1,328 of its 1,817 scored suburbs carry their own Water Corporation scheme or locality’s 2024-25 readings; the rest, mostly remote stations, mining towns and places other utilities supply, still share their region’s readings. Perth suburbs run from 8.5 in the Mundaring locality (pH 8.55, just over the aesthetic range) to 9.6 in Dwellingup and North Dandalup; our Perth hardness article lists every locality.

Queensland’s figures cover South East Queensland only, because most regional Queensland councils publish little data we can load. South Australia has the most suburbs scored (2,084) thanks to SA Water’s zone-level reporting.

How Australian Water Compares to ADWG Guidelines

The Australian Drinking Water Guidelines set health-based and aesthetic benchmarks for drinking water. Where suburbs differ most is on the aesthetic parameters. The ADWG recommends:

• Hardness: below 200 mg/L (aesthetic)
• TDS: below 600 mg/L (aesthetic)
• Sodium: below 180 mg/L (aesthetic)
• Chloride: below 250 mg/L (aesthetic)
• pH: 6.5 to 8.5 (aesthetic)
• Chlorine: below 5 mg/L (health)
• Fluoride: below 1.5 mg/L (health)

Most top-scoring suburbs sit well within all of these limits. The hardest water suburbs exceed the 200 mg/L hardness guideline by up to three times, but this is an aesthetic concern, not a health risk. Your body needs calcium and magnesium; hard water simply delivers more of those minerals than most people prefer in their tea.

The ADWG also sets guideline values for emerging contaminants like PFAS. For the latest results by city, see our PFAS in Australian tap water research.

For a suburb-level comparison against these guidelines, use our water hardness calculator or check your suburb’s individual report.

What You Can Do

Whether your suburb ranks at the top or the bottom, there are practical steps to understand and improve your water.

1. Check your suburb’s report. Search for your suburb on WaterScore to see a full breakdown of measured parameters, your WaterScore rating, and how it compares to the ADWG guidelines and state averages.

2. Understand what the score means. A WaterScore of 7.9 does not mean unsafe water. It means some aesthetic parameters sit further from ideal values. Read the individual parameter readings on your suburb page to understand the specifics.

3. Consider a filter if hardness is high. If your suburb records hardness above 200 mg/L, a reverse osmosis system removes minerals effectively. For chlorine taste, a simple activated carbon filter works well. See our best water filter guide or check the filter recommendation for Adelaide if you are in a hard water area.

4. Test your water at home. A TDS meter (under $20) gives you a quick mineral content reading. Test strips for hardness, pH, and chlorine are available from hardware stores and provide a useful cross-check against utility data.

5. Contact your utility. If you have concerns about specific parameters, your local water utility publishes annual water quality reports. SA Water, Sydney Water, and other utilities provide detailed zone-level data on request.

Frequently Asked Questions

Which suburb has the best water quality in Australia?

106 suburbs share the top WaterScore of 9.8 out of 10. 102 of them are in Tasmania, 83 in Greater Hobart, including Howrah, Bellerive, Lindisfarne, Sorell and Midway Point. The others are three remote South Australian communities, Oak Valley, Nullarbor and Yunyarinyi, and Jerramungup in Western Australia. They share soft water, from 7 to 46 mg/L hardness, with low dissolved solids.

Which suburb has the worst water quality in Australia?

Horrocks, a small coastal town in Western Australia’s Mid West, records the lowest WaterScore at 7.5 out of 10. Water Corporation’s 2024-25 figures show 1,305 mg/L of dissolved solids, 399 mg/L of sodium and 606 mg/L of chloride, all above the aesthetic guidelines. Guilderton and New Norcia, also in the Mid West, follow at 7.8, then SA Water’s Geranium system, including Wilkawatt, at 7.9. These affect taste and scale, and none of the readings breaks a health-based guideline.

Which state has the best tap water in Australia?

On our data, the ACT has the highest average WaterScore at 9.70, followed by Tasmania at 9.64 and New South Wales at 9.54. Victoria averages 9.45. Western Australia has the lowest average at 9.05, held down by salty, hard groundwater in Mid West and Wheatbelt towns.

Is low-scoring water unsafe to drink?

No. A lower WaterScore does not mean the water is unsafe. The score reflects how far each reading sits from ideal values across hardness, chlorine, minerals and other parameters. The lowest-scoring suburbs in our data exceed the aesthetic guidelines for hardness, sodium and chloride, which affect taste and scale, not the ADWG health-based guidelines.

How can I check the water quality in my suburb?

Search for your suburb on WaterScore.com.au to see a detailed breakdown of measured water quality parameters, your suburb’s WaterScore rating, and how it compares to state and national averages. Each suburb page shows hardness, pH, chlorine, fluoride, and other key readings from your local water utility. You can also compare two suburbs side by side.

Summary

The best water quality suburbs in Australia cluster in Tasmania, where 102 suburbs, mostly in Greater Hobart, share the top score of 9.8, with Canberra close behind at 9.7. The lowest-scoring suburbs are groundwater towns in Western Australia’s Mid West and regional South Australia, on hard or salty water, and even they meet the health-based guidelines. Check your suburb’s report on WaterScore to see where you stand among the best water quality suburbs in Australia.

Sources

1. Australian Drinking Water Guidelines (ADWG), National Health and Medical Research Council, 2025
2. SA Water Annual Water Quality Data, SA Water, December 2024 to November 2025 reporting period
3. Melbourne Water Annual Report, Melbourne Water, 2024-25
4. Drinking Water Quality Report 2024-25, Icon Water
5. TasWater Annual Drinking Water Quality Report, TasWater, 2024-25
6. Seqwater Water Quality Reporting, Seqwater, 2024-25
7. Water Corporation Water Quality Annual Report, Water Corporation, 2024-25