Is Perth's water hard?

It varies a lot by suburb. Perth has the widest hardness range of any Australian capital. The soft south sits under 60 mg/L, while the groundwater-fed north and inner-north run 120 to 228 mg/L with high silica, which is rough on glass and stone. Read your zone, not the city average.

Why does my Perth glass keep spotting?

Hard, mineral-rich water dries on the glass and leaves calcium carbonate and silica. Under the sun, and especially where reticulation sprays the glass, it bakes into a hard scale. Caught fresh it wipes off; left to cement it becomes insoluble and eventually etches the glass.

Can baked-on hard water stains be removed from glass?

Fresh spotting wipes off. Once the deposit cements and the silica sets, ordinary cleaners cannot shift it and acids only remove the calcium half, not the silica. At that point it needs professional mechanical restoration, and if the glass is etched, restoration or replacement is the only fix.

A frameless glass pool fence in a Perth backyard

WA water tool

What's in your WA water?

WA water runs the full range, from soft, forest-fed towns to very hard, mineral-rich groundwater, and it is rougher on glass and stone than most people realise. It changes a lot from one town to the next, so soft doesn't always mean safe, and the next town over tells you nothing about yours. Find your area, see what your water is actually doing to your surfaces, and get a straight answer on how to stay ahead of it.

Water risk to surfaces Low Moderate High Severe

Your suburb, your water

Get your suburb's water report and a fixed quote.

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The honest version

Why WA water is rough on glass.

This tool shows the honest risk your surfaces face from WA's hard, silica-rich water, and how far the right coating plus a bit of habit can shift the odds. It does not promise to stop the chemistry. It shows you how to reduce the load, slow the damage, and stay out of the restoration pathway.

Figures are per Water Corporation supply zone, not per street, so your exact tap values move with season and source blend. Private bore and reticulation water is untreated groundwater set by local geology, is usually at least as hard as scheme water in the same area, and varies property to property, so if you are on a bore get your own test. Everything here is about reducing and slowing hard-water damage, not stopping it.

Zone by zone

WA water, by supply zone.

Hardness and silica in mg/L, TDS in mg/L, from Water Corporation's per-zone drinking-water data across 220 WA supply zones. Silica is the acid-resistant one that ordinary cleaners cannot shift. Grouped by region — tap a region to open it.

Perth & Peel40 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Guilderton Guilderton	340	8.8	1118	very hard	Severe
Lancelin Lancelin	293	15.5	800	very hard	Severe
Preston Beach Preston Beach	290	16.3	775	very hard	Severe
Ledge Point Ledge Point	245	14.5	666	very hard	Severe
Two Rocks Two Rocks, Alkimos	228	11.3	525	very hard	Severe
Nilgen (Ocean Farms) Nilgen, Ocean Farms	213	18	610	very hard	Severe
Yanchep Yanchep, Butler, Eglinton	198	19.5	576	very hard	Severe
Neerabup Clarkson, Quinns Rocks, Merriwa, Mindarie	190	20.5	572	very hard	Severe
Wanneroo Wanneroo, Landsdale, Madeley	125	17.5	480	hard	Severe
West Yokine West Yokine, Joondanna	123	16	535	hard	Severe
Whitfords Joondalup, Hillarys, Iluka, Kallaroo, Padbury, Whitford…	113	17.3	458	moderate	Severe
Mt Yokine Mt Yokine, Tuart Hill, Yokine	108	17.8	554	moderate	Severe
Mt Hawthorn Mt Hawthorn, Leederville, North Perth	106	17.2	572	moderate	Severe
Seabird Seabird	97	17	587	moderate	Severe
South Perth/Kewdale South Perth, Kewdale	94	14.5	542	moderate	Severe
Bindoon/Chittering Bindoon, Chittering	50	36	483	soft	Severe
Woodridge Woodridge	46	24	481	soft	Severe
Gingin Gingin	32	29.6	276	soft	Severe
Mirrabooka Mirrabooka, Balga, Nollamara, Westminster	124	15.4	517	hard	High
Lexia Ellenbrook, Upper Swan, The Vines	118	15.5	403	moderate	High
Greenmount Greenmount, Darlington	95	13.5	488	moderate	High
Peppermint Grove Peppermint Grove Beach	56	15	291	soft	High
Mundaring Mundaring	98	5.6	467	moderate	Moderate
Thomsons Lake Cockburn	89	4.7	431	moderate	Moderate
Hamilton Hill Hamilton Hill	79	3.1	405	moderate	Moderate
Armadale/Kelmscott Armadale, Kelmscott	75	2.6	391	moderate	Moderate
Foothills	75	4.2	430	moderate	Moderate
Mt Eliza	69	—	444	moderate	Moderate
Buckland Hill Mosman Park	63	5.8	396	moderate	Moderate
Bold Park City Beach	62	—	286	moderate	Moderate
Melville Melville, Willagee, Palmyra	54	4.7	356	soft	Low
Tamworth Hill	53	1	129	soft	Low
Waroona Waroona	52	4	151	soft	Low
Yarloop Yarloop	51	1.4	144	soft	Low
Mandurah Mandurah, Halls Head, Greenfields	50	1.3	147	soft	Low
Hills Direct	48	1.8	183	soft	Low
Pinjarra Pinjarra	46	1.7	154	soft	Low
North Dandalup North Dandalup	42	1.2	155	soft	Low
Boddington Boddington	36	3.9	161	soft	Low
Dwellingup Dwellingup	29	1.7	142	soft	Low

South West34 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Walpole Walpole, Nornalup	119	31.2	517	moderate	Severe
Eaton Eaton, Millbridge	118	30.5	433	moderate	Severe
Boyanup Boyanup	105	18.8	387	moderate	Severe
Australind Australind, Leschenault, Kingston	85	43.3	543	moderate	Severe
Brunswick Junction Brunswick Junction, Brunswick	83	47	559	moderate	Severe
Dunsborough Dunsborough, Quindalup, Eagle Bay, Naturaliste	81	16.8	542	moderate	Severe
Dardanup Dardanup	28	20.5	300	soft	Severe
Hester Hester	135	10.1	381	hard	High
Balingup Balingup	130	8.4	374	hard	High
Boyup Brook Boyup Brook	128	9	379	hard	High
Greenbushes Greenbushes	125	11.9	370	hard	High
Mullalyup Mullalyup	125	10.5	367	hard	High
Kirup Kirup	123	9.9	374	hard	High
Dalyellup Dalyellup	79	16.5	422	moderate	High
Augusta Augusta	74	14.5	334	moderate	High
Donnybrook Donnybrook	67	15	461	moderate	High
Capel Capel	47	14	261	soft	High
Bridgetown Bridgetown	120	8.4	363	moderate	Moderate
Bunbury (Aqwest) Bunbury, East Bunbury, South Bunbury, Carey Park, Withers, Usher…	100	—	—	moderate	Moderate
Manjimup Manjimup	91	4.9	283	moderate	Moderate
Logue Brook Logue Brook, Cookernup	62	6.9	202	moderate	Moderate
Quinninup Quinninup	56	6	252	soft	Low
Myalup Myalup	53	3.4	155	soft	Low
Pemberton Pemberton	53	5.8	252	soft	Low
Binningup Binningup	52	3.6	152	soft	Low
Northcliffe Northcliffe	51	5.2	249	soft	Low
Nannup Nannup	50	6.4	225	soft	Low
Harvey Harvey	49	3.2	149	soft	Low
Darkan Darkan	44	4.4	179	soft	Low
Margaret River Margaret River	42	9.4	257	soft	Low
Cowaramup Cowaramup	41	9.5	251	soft	Low
Allanson Allanson	38	2.4	177	soft	Low
Collie Collie	37	3.3	173	soft	Low
Williams Williams	34	3.4	160	soft	Low

Great Southern16 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Rocky Gully Rocky Gully	273	15.3	627	very hard	Severe
Kendenup Kendenup	265	14.5	615	very hard	Severe
Porongurup Porongurup	263	14	605	very hard	Severe
Mount Barker Mount Barker	260	14.5	600	very hard	Severe
Narrikup Narrikup	260	15	603	very hard	Severe
Wellstead Wellstead	258	13.8	608	very hard	Severe
Albany Albany, Yakamia, Spencer Park, Mira Mar, Mount Melville, Mount Clarence…	255	14.7	598	very hard	Severe
Bremer Bay Bremer Bay	223	49.5	824	very hard	Severe
Denmark Denmark, Ocean Beach	173	9.9	551	hard	Severe
Hopetoun Hopetoun	143	25	656	hard	Severe
Ravensthorpe Ravensthorpe	71	15.6	438	moderate	High
Kojonup Kojonup	50	1.7	195	soft	Low
Broomehill Broomehill	48	1.6	190	soft	Low
Katanning Katanning	45	1.1	186	soft	Low
Woodanilling Woodanilling	41	3	169	soft	Low
Wagin Wagin	39	3.1	172	soft	Low

Wheatbelt67 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Watheroo Watheroo	268	12.3	678	very hard	Severe
New Norcia New Norcia	177	35.8	992	hard	Severe
Piawaning Piawaning	172	18.6	776	hard	Severe
Yerecoin Yerecoin	162	19.6	752	hard	Severe
Calingiri Calingiri	159	14.6	815	hard	Severe
Carnamah Carnamah	138	25	840	hard	Severe
Bolgart Bolgart	128	38.8	567	hard	Severe
Coorow Coorow	125	28.6	831	hard	Severe
Buntine Buntine	120	5.4	531	moderate	Severe
Dandaragan Dandaragan	96	39	753	moderate	Severe
Latham Latham	93	43.6	722	moderate	Severe
Perenjori Perenjori	83	46	687	moderate	Severe
Coomberdale Coomberdale	81	21	609	moderate	Severe
Morawa Morawa	74	45	669	moderate	Severe
Moora Moora	73	22	598	moderate	Severe
Badgingarra Badgingarra	42	41.7	539	soft	Severe
Bencubbin Bencubbin	115	5.6	508	moderate	Moderate
Ballidu Ballidu	110	5.1	492	moderate	Moderate
Shackleton Shackleton	110	5.3	477	moderate	Moderate
Wubin Wubin	110	5	486	moderate	Moderate
Bindi Bindi Bindi Bindi	105	5.2	491	moderate	Moderate
Cadoux Cadoux	105	5.3	494	moderate	Moderate
Greater Bodallin Bodallin	105	5.2	487	moderate	Moderate
Jennacubbine Jennacubbine	105	5.3	470	moderate	Moderate
Marvel Loch Marvel Loch	105	5.3	483	moderate	Moderate
Miling Miling	105	5.8	493	moderate	Moderate
Pithara Pithara	105	5.1	493	moderate	Moderate
Quairading Quairading	105	5	477	moderate	Moderate
Kununoppin Kununoppin	104	6	471	moderate	Moderate
Trayning Trayning	104	5.5	478	moderate	Moderate
Bullfinch Bullfinch	103	5.8	484	moderate	Moderate
Southern Cross Southern Cross	103	6.1	466	moderate	Moderate
Dalwallinu Dalwallinu	101	5.7	474	moderate	Moderate
Beacon Beacon	100	5.8	479	moderate	Moderate
Bruce Rock Bruce Rock	100	5.9	474	moderate	Moderate
Corrigin Corrigin	100	5.2	480	moderate	Moderate
Cunderdin Cunderdin	100	5.7	485	moderate	Moderate
Greater Burracoppin Burracoppin	100	5.5	480	moderate	Moderate
Greater Meckering Meckering	100	5.5	488	moderate	Moderate
Kalannie Kalannie	100	5.6	498	moderate	Moderate
Koorda Koorda	100	5.3	486	moderate	Moderate
Merredin Merredin	100	5.5	484	moderate	Moderate
Muntadgin Muntadgin	100	5	481	moderate	Moderate
Narembeen Narembeen	100	5.4	490	moderate	Moderate
Nungarin Nungarin	100	5.1	482	moderate	Moderate
Seabrook Seabrook	100	5.5	474	moderate	Moderate
Spencers Brook Spencers Brook	100	5.6	472	moderate	Moderate
Wongan Hills Wongan Hills	100	5	480	moderate	Moderate
Wyalkatchem Wyalkatchem	100	5	480	moderate	Moderate
Ardath Ardath	99	5.3	482	moderate	Moderate
Dowerin Dowerin	99	5.8	478	moderate	Moderate
Northam Northam	99	5.1	462	moderate	Moderate
Warralakin Warralakin	98	5.8	472	moderate	Moderate
Avon Hills Avon Hills	97	6.1	465	moderate	Moderate
Beverley Beverley	97	5.2	471	moderate	Moderate
Greater Doodlakine Doodlakine	97	5.7	468	moderate	Moderate
Kellerberrin Kellerberrin	97	5.2	465	moderate	Moderate
Mukinbudin Mukinbudin	97	5.6	476	moderate	Moderate
Tammin Tammin	97	6.1	464	moderate	Moderate
Westonia Westonia	97	5.6	467	moderate	Moderate
Goomalling Goomalling	95	5.8	465	moderate	Moderate
Toodyay Toodyay	95	5.4	467	moderate	Moderate
York York	95	5.3	470	moderate	Moderate
Wandering Wandering	39	4.1	172	soft	Low
Cuballing Cuballing	37	3	166	soft	Low
Highbury Highbury	36	3.1	167	soft	Low
Narrogin Narrogin	36	3	167	soft	Low

Mid West24 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Cervantes Cervantes	328	14	972	very hard	Severe
Jurien Bay Jurien Bay	314	12.9	991	very hard	Severe
Sovereign Hills Sovereign Hills	252	19.2	695	very hard	Severe
Seaview Park Seaview Park	188	16	503	very hard	Severe
Horrocks Horrocks	133	14.8	1305	hard	Severe
Mullewa Mullewa	132	22.2	884	hard	Severe
Northampton Northampton	130	22	887	hard	Severe
Dongara/Denison Dongara, Port Denison	122	22.2	880	hard	Severe
Nabawa Nabawa	122	22.8	865	hard	Severe
Yuna Yuna	120	22.4	870	moderate	Severe
Geraldton Geraldton, Bluff Point, Beresford, Mount Tarcoola, Tarcoola Beach, Wonthella…	119	22.6	854	moderate	Severe
Port Kalbarri Port Kalbarri	115	43.5	824	moderate	Severe
Greenhead Greenhead	110	23	578	moderate	Severe
Leeman Leeman	105	23.5	595	moderate	Severe
Eneabba Eneabba	102	43	660	moderate	Severe
Mingenew Mingenew	101	52.5	797	moderate	Severe
Three Springs Three Springs	90	48	750	moderate	Severe
Wiluna Wiluna	65	84.2	380	moderate	Severe
Sandstone Sandstone	63	34.6	393	moderate	Severe
Kalbarri Kalbarri	58	41	376	soft	Severe
Mt Magnet Mount Magnet	58	77	448	soft	Severe
Meekatharra Meekatharra	50	75	439	soft	Severe
Yalgoo Yalgoo	41	84	368	soft	Severe
Cue Cue	39	79	377	soft	Severe

Gascoyne6 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Exmouth Exmouth	328	15.8	847	very hard	Severe
Onslow Onslow	168	75	477	hard	Severe
Carnarvon Carnarvon	155	41	503	hard	Severe
Coral Bay Coral Bay	77	—	177	moderate	Moderate
Gascoyne Junction Gascoyne Junction	65	4.4	259	moderate	Moderate
Denham Denham	64	1.5	272	moderate	Moderate

Goldfields–Esperance16 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Grass Patch Grass Patch	358	11.1	834	very hard	Severe
Munglinup Munglinup	348	11	821	very hard	Severe
Salmon Gums Salmon Gums	348	10.4	831	very hard	Severe
Esperance Esperance, Castletown, West Beach, Nulsen, Sinclair, Chadwick…	340	11.1	828	very hard	Severe
Leonora Leonora, Gwalia	143	31.8	657	hard	Severe
Condingup Condingup	76	65	1014	moderate	Severe
Laverton Laverton	74	32.2	466	moderate	Severe
Gibson Gibson	42	45.4	667	soft	Severe
Ora Banda Ora Banda	115	6	502	moderate	Moderate
Menzies Menzies	110	5.5	508	moderate	Moderate
Norseman Norseman	110	5.5	486	moderate	Moderate
Broad Arrow Broad Arrow	105	5.3	488	moderate	Moderate
Kalgoorlie Kalgoorlie, Boulder, South Boulder, Lamington, Williamstown, Hannans…	105	5.6	476	moderate	Moderate
Kambalda Kambalda West, Kambalda East	105	6	482	moderate	Moderate
Koolyanobbing Koolyanobbing	99	5.8	470	moderate	Moderate
Coolgardie Coolgardie	97	5.7	473	moderate	Moderate

Pilbara10 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Cape Lambert Cape Lambert	280	60	687	very hard	Severe
Karratha Karratha, Bulgarra, Nickol, Millars Well, Pegs Creek, Baynton…	280	39	752	very hard	Severe
Marble Bar Marble Bar	275	40	965	very hard	Severe
Burrup (Dampier) Dampier, Burrup Peninsula	265	60	629	very hard	Severe
Wickham Wickham	265	55	649	very hard	Severe
Roebourne Roebourne	260	55	631	very hard	Severe
Hedland (Port Hedland / South Hedland) Port Hedland, South Hedland, Wedgefield, Pretty Pool, Cooke Point, Koombana	218	53	604	very hard	Severe
Point Samson Point Samson	195	53	468	very hard	Severe
Nullagine Nullagine	180	34	507	hard	Severe
Newman Newman	150	16	406	hard	High

Kimberley7 zones

Zone & suburbs	Hardness	Silica	TDS	Band	Risk
Halls Creek Halls Creek	335	47	974	very hard	Severe
Fitzroy Crossing Fitzroy Crossing, Bungardi, Mindi Rardi	165	21	407	hard	Severe
Kununurra Kununurra, Lakeside, White Gum Park	158	54	399	hard	Severe
Broome Broome, Cable Beach, Djugun, Bilingurr, Minyirr, Roebuck Estate…	48	95	394	soft	Severe
Camballin Camballin	43	23	234	soft	Severe
Derby Derby	16	15	431	soft	High
Wyndham Wyndham, Wyndham East, Three Mile	49	9	145	soft	Low

What it means

What each risk level does to your surfaces.

Glass

The worst water in the metro can ruin glass in a single summer.

Every drying droplet lays down calcite plus a hard, glassy, insoluble silica film. On bore water it adds an orange-brown iron stain as well.

Under the sun those layers cement fast and heavy, the barnacle-like scale you see where reticulation hits the glass. Prolonged contact turns the water alkaline and etches and pits the glass itself.

If you leave itLeft one summer, the scale bakes on permanently and the glass etches; only mechanical restoration or replacing the panel remains.

Stone & finishes

Highest hardness plus salt: the stone face itself is lost, not just dirty.

The most mineral-loaded water bakes into an insoluble calcite-and-silica crust within a very short window. The silica polymerises into a glass-like film anchored deep in the stone's pore network.

Worse, salt crystallising below the surface exerts pressure that fractures the stone from inside, spalling, flaking and pitting the face. Tamala and other porous limestones are the textbook worst case.

If you leave itOnce the face spalls or pits, cleaning is finished: only mechanical restoration where enough stone remains, or replacing it.

Stay ahead of it

Protect it before the water bakes in.

Once hard-water scale cements and etches, no cleaner reverses it, and the only path is professional restoration or replacement. A coating that reduces how much bonds, plus smarter reticulation, keeps you out of that pathway.

Get a free surface assessment How glass protection works

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