How hard is my water?
Put in your postcode and see how hard your water is, who supplies it, and whether it is hard enough to be worth softening. Free, instant, no email needed.
Rain is soft when it lands. It picks up calcium and magnesium on its way through porous rock, which is why the chalk and limestone of the South and East give the hardest water in the country, and the granite of Scotland, Wales and the West Country gives the softest.
Tap any area name on the map to list the postcodes in it, or put your postcode in above for a figure and a recommendation.
What the bands mean
- Soft0–50 mg/lVery little scale. Soap lathers easily.
- Moderately soft50–100 mg/lScale is rare and easy to wipe away.
- Slightly hard100–150 mg/lA light film on the kettle over time.
- Moderately hard150–200 mg/lVisible scale in the kettle and on taps.
- Hard200–275 mg/lScale builds quickly. Appliances work harder.
- Very hard275+ mg/lHeavy scale. Kettles and boilers suffer.
The UK hard water map
Coastline from Ordnance Survey and OSNI open boundary data. The shading is worked out from the published figure for every one of the 124 postcode areas, blended across the country and snapped to the six bands. It shows the shape of the thing, not a boundary any water company would recognise, so check your own postcode for a real figure.
Every UK postcode area
| Area | Covering | Typical hardness | Band | Supplier |
|---|---|---|---|---|
| AB | Aberdeen | 20–60 mg/l | Soft | Scottish Water |
| AL | St Albans | 270–340 mg/l | Very hard | Affinity Water |
| B | Birmingham | 30–80 mg/l | Moderately soft | Severn Trent |
| BA | Bath | 220–300 mg/l | Hard | Wessex Water |
| BB | Blackburn | 15–50 mg/l | Soft | United Utilities |
| BD | Bradford | 20–70 mg/l | Soft | Yorkshire Water |
| BH | Bournemouth | 220–300 mg/l | Hard | Wessex Water |
| BL | Bolton | 15–50 mg/l | Soft | United Utilities |
| BN | Brighton | 250–330 mg/l | Very hard | Southern Water |
| BR | Bromley | 250–320 mg/l | Very hard | Thames Water |
| BS | Bristol | 200–300 mg/l | Hard | Bristol Water |
| BT | Belfast & Northern Ireland | 30–90 mg/l | Moderately soft | NI Water |
| CA | Carlisle | 15–60 mg/l | Soft | United Utilities |
| CB | Cambridge | 280–350 mg/l | Very hard | Cambridge Water |
| CF | Cardiff | 60–120 mg/l | Moderately soft | Dŵr Cymru Welsh Water |
| CH | Chester | 60–180 mg/l | Slightly hard | United Utilities |
| CM | Chelmsford | 250–330 mg/l | Very hard | Essex & Suffolk Water |
| CO | Colchester | 280–350 mg/l | Very hard | Essex & Suffolk Water |
| CR | Croydon | 250–320 mg/l | Very hard | SES Water |
| CT | Canterbury | 250–330 mg/l | Very hard | South East Water |
| CV | Coventry | 200–300 mg/l | Hard | Severn Trent |
| CW | Crewe | 100–250 mg/l | Moderately hard | United Utilities |
| DA | Dartford | 250–330 mg/l | Very hard | Thames Water |
| DD | Dundee | 30–70 mg/l | Soft | Scottish Water |
| DE | Derby | 150–280 mg/l | Hard | Severn Trent |
| DG | Dumfries | 20–50 mg/l | Soft | Scottish Water |
| DH | Durham | 60–150 mg/l | Slightly hard | Northumbrian Water |
| DL | Darlington | 40–120 mg/l | Moderately soft | Northumbrian Water |
| DN | Doncaster | 150–280 mg/l | Hard | Yorkshire Water |
| DT | Dorchester | 220–300 mg/l | Hard | Wessex Water |
| DY | Dudley | 150–280 mg/l | Hard | Severn Trent |
| E | East London | 250–320 mg/l | Very hard | Thames Water |
| EC | City of London | 250–320 mg/l | Very hard | Thames Water |
| EH | Edinburgh | 30–90 mg/l | Moderately soft | Scottish Water |
| EN | Enfield | 250–320 mg/l | Very hard | Thames Water |
| EX | Exeter | 30–120 mg/l | Moderately soft | South West Water |
| FK | Falkirk | 20–50 mg/l | Soft | Scottish Water |
| FY | Blackpool | 20–60 mg/l | Soft | United Utilities |
| G | Glasgow | 15–40 mg/l | Soft | Scottish Water |
| GL | Gloucester | 180–300 mg/l | Hard | Severn Trent |
| GU | Guildford | 220–320 mg/l | Hard | South East Water |
| GY | Guernsey | 100–200 mg/l | Slightly hard | Guernsey Water |
| HA | Harrow | 250–320 mg/l | Very hard | Affinity Water |
| HD | Huddersfield | 15–60 mg/l | Soft | Yorkshire Water |
| HG | Harrogate | 80–200 mg/l | Slightly hard | Yorkshire Water |
| HP | Hemel Hempstead | 260–340 mg/l | Very hard | Affinity Water |
| HR | Hereford | 180–300 mg/l | Hard | Severn Trent |
| HS | Outer Hebrides | 10–40 mg/l | Soft | Scottish Water |
| HU | Hull | 250–330 mg/l | Very hard | Yorkshire Water |
| HX | Halifax | 15–55 mg/l | Soft | Yorkshire Water |
| IG | Ilford | 250–320 mg/l | Very hard | Essex & Suffolk Water |
| IM | Isle of Man | 60–160 mg/l | Slightly hard | Manx Utilities |
| IP | Ipswich | 280–350 mg/l | Very hard | Essex & Suffolk Water |
| IV | Inverness | 10–40 mg/l | Soft | Scottish Water |
| JE | Jersey | 100–220 mg/l | Moderately hard | Jersey Water |
| KA | Kilmarnock | 15–45 mg/l | Soft | Scottish Water |
| KT | Kingston upon Thames | 250–320 mg/l | Very hard | SES Water |
| KW | Kirkwall & Caithness | 15–50 mg/l | Soft | Scottish Water |
| KY | Kirkcaldy | 30–80 mg/l | Moderately soft | Scottish Water |
| L | Liverpool | 20–60 mg/l | Soft | United Utilities |
| LA | Lancaster | 20–60 mg/l | Soft | United Utilities |
| LD | Llandrindod Wells | 20–60 mg/l | Soft | Dŵr Cymru Welsh Water |
| LE | Leicester | 220–320 mg/l | Hard | Severn Trent |
| LL | Llandudno | 20–70 mg/l | Soft | Dŵr Cymru Welsh Water |
| LN | Lincoln | 250–330 mg/l | Very hard | Anglian Water |
| LS | Leeds | 40–120 mg/l | Moderately soft | Yorkshire Water |
| LU | Luton | 280–350 mg/l | Very hard | Affinity Water |
| M | Manchester | 15–45 mg/l | Soft | United Utilities |
| ME | Medway | 250–330 mg/l | Very hard | South East Water |
| MK | Milton Keynes | 250–330 mg/l | Very hard | Anglian Water |
| ML | Motherwell | 15–45 mg/l | Soft | Scottish Water |
| N | North London | 250–320 mg/l | Very hard | Thames Water |
| NE | Newcastle upon Tyne | 30–90 mg/l | Moderately soft | Northumbrian Water |
| NG | Nottingham | 150–280 mg/l | Hard | Severn Trent |
| NN | Northampton | 250–330 mg/l | Very hard | Anglian Water |
| NP | Newport | 80–160 mg/l | Slightly hard | Dŵr Cymru Welsh Water |
| NR | Norwich | 280–350 mg/l | Very hard | Anglian Water |
| NW | North West London | 250–320 mg/l | Very hard | Thames Water |
| OL | Oldham | 15–45 mg/l | Soft | United Utilities |
| OX | Oxford | 250–330 mg/l | Very hard | Thames Water |
| PA | Paisley | 15–40 mg/l | Soft | Scottish Water |
| PE | Peterborough | 250–350 mg/l | Very hard | Anglian Water |
| PH | Perth | 20–60 mg/l | Soft | Scottish Water |
| PL | Plymouth | 20–70 mg/l | Soft | South West Water |
| PO | Portsmouth | 220–320 mg/l | Hard | Portsmouth Water |
| PR | Preston | 15–50 mg/l | Soft | United Utilities |
| RG | Reading | 240–330 mg/l | Very hard | Thames Water |
| RH | Redhill | 220–320 mg/l | Hard | SES Water |
| RM | Romford | 250–330 mg/l | Very hard | Essex & Suffolk Water |
| S | Sheffield | 30–100 mg/l | Moderately soft | Yorkshire Water |
| SA | Swansea | 20–70 mg/l | Soft | Dŵr Cymru Welsh Water |
| SE | South East London | 250–320 mg/l | Very hard | Thames Water |
| SG | Stevenage | 270–340 mg/l | Very hard | Affinity Water |
| SK | Stockport | 20–60 mg/l | Soft | United Utilities |
| SL | Slough | 250–330 mg/l | Very hard | Thames Water |
| SM | Sutton | 250–320 mg/l | Very hard | SES Water |
| SN | Swindon | 250–330 mg/l | Very hard | Thames Water |
| SO | Southampton | 180–300 mg/l | Hard | Southern Water |
| SP | Salisbury | 240–320 mg/l | Very hard | Wessex Water |
| SR | Sunderland | 100–200 mg/l | Slightly hard | Northumbrian Water |
| SS | Southend-on-Sea | 260–340 mg/l | Very hard | Essex & Suffolk Water |
| ST | Stoke-on-Trent | 120–250 mg/l | Moderately hard | Severn Trent |
| SW | South West London | 250–320 mg/l | Very hard | Thames Water |
| SY | Shrewsbury | 100–250 mg/l | Moderately hard | Severn Trent |
| TA | Taunton | 150–280 mg/l | Hard | Wessex Water |
| TD | Galashiels | 30–90 mg/l | Moderately soft | Scottish Water |
| TF | Telford | 150–260 mg/l | Hard | Severn Trent |
| TN | Tunbridge Wells | 180–300 mg/l | Hard | South East Water |
| TQ | Torquay | 30–100 mg/l | Moderately soft | South West Water |
| TR | Truro | 15–60 mg/l | Soft | South West Water |
| TS | Teesside | 60–160 mg/l | Slightly hard | Northumbrian Water |
| TW | Twickenham | 250–320 mg/l | Very hard | Thames Water |
| UB | Uxbridge | 250–320 mg/l | Very hard | Affinity Water |
| W | West London | 250–320 mg/l | Very hard | Thames Water |
| WA | Warrington | 25–90 mg/l | Moderately soft | United Utilities |
| WC | Central London | 250–320 mg/l | Very hard | Thames Water |
| WD | Watford | 270–340 mg/l | Very hard | Affinity Water |
| WF | Wakefield | 60–160 mg/l | Slightly hard | Yorkshire Water |
| WN | Wigan | 20–60 mg/l | Soft | United Utilities |
| WR | Worcester | 150–280 mg/l | Hard | Severn Trent |
| WS | Walsall | 120–260 mg/l | Moderately hard | Severn Trent |
| WV | Wolverhampton | 100–240 mg/l | Moderately hard | Severn Trent |
| YO | York | 150–280 mg/l | Hard | Yorkshire Water |
| ZE | Shetland | 10–40 mg/l | Soft | Scottish Water |
What hard water actually costs you
Hard water is safe to drink. The damage is done when you heat it. Above about 60°C the dissolved calcium comes out of solution and sticks to whatever is hottest, which is the element in your kettle, your boiler and your dishwasher.
Your boiler works harder
A coating of scale sits between the element and the water. The boiler has to burn longer to reach the same temperature, and the element runs hotter than it was designed to, which is what eventually kills it.
Appliances fail sooner
Kettles, dishwashers, washing machines and coffee machines all heat water. In a very hard area they scale up in months rather than years, and descaling only removes what is loose.
It shows on everything
White film on glasses, spots on chrome, a skin on hot drinks, and more soap and shampoo needed for the same lather. None of it is dirt. It is the minerals.
Filters clog faster
Any filtered or boiling tap fitted in a hard area works through cartridges quicker. Softening in front of the unit is cheaper than replacing cartridges early, and it protects the tank and element behind them.
What we fit in a hard water area
Two different jobs. A softener on the incoming mains protects the whole property, which is what hard water really costs you. A RoyalFlow stage protects the tap. Above 200 mg/l we would fit the first before the second, sized to your water rather than sold by default.
- Up to 100 mg/lHome Basic, included
Soft water. The built-in carbon filtration and UV are all you need, and a softener would have almost nothing to take out.
- 100 to 200 mg/lHome Basic+
A sediment pre-filter to protect the unit and keep the taste clean. Softening the mains here is a comfort choice rather than a necessity.
- 200 mg/l and aboveA Regal softener on the mains
This is the one that saves money. A whole-property softener treats the water as it enters the house, so the boiler, the shower, the washing machine and the pipework are all protected, not just the tap. The tap then needs only Home Basic+ behind it.
- Hard water, tap onlyHome Soft+
If you are not softening the whole property, this adds a sediment pre-filter and a floorstanding resin cartridge in front of the RoyalFlow unit alone, so at least the tap and its cartridges survive the hardness.
- Any hardnessHome Taste+
Sediment pre-filter, a compact reverse osmosis unit and a slim remineraliser cartridge, on top of the built-in carbon and UV. For the purest water and a controlled mineral profile at the tap.
Questions people ask
How is water hardness measured?
In milligrams of calcium carbonate per litre, written mg/l or ppm. Water companies in the UK publish the same figure, sometimes also as degrees Clark or French. Below 100 mg/l counts as soft, above 200 as hard, and above 275 as very hard.
Why does hardness change street by street?
Water companies blend sources, and a single postcode area can be fed by more than one treatment works. The figures here are the typical range for the whole area, which is why every result links to your own supplier's postcode tool for the exact number.
Is hard water bad for you?
No. Hard water is safe to drink and the calcium and magnesium in it are the same minerals found in food. The problem is scale: it coats kettle elements, narrows pipework, and makes boilers and dishwashers work harder and fail sooner.
Should I soften the whole house, or just the tap?
In a hard area, the whole house. A tap filter protects the tap and nothing else, so the same hard water still reaches your boiler, your shower, your washing machine and the pipework, which is where scale costs real money. A Regal softener sits on the incoming mains and treats everything. Softening only at the tap is the answer when you want better drinking water but your water is not hard enough to threaten the appliances.
If I soften the whole house, do I still need Home Soft+ on the tap?
No. Home Soft+ adds a resin cartridge in front of the RoyalFlow unit, and once the mains is softened that water is already soft. The unit then needs only the sediment pre-filter in Home Basic+. Fitting both would be paying twice for the same job.
Does a RoyalFlow tap need a softener?
Not always. Every RoyalFlow unit filters through carbon and UV as standard, which handles taste and safety. If your mains is not softened and the water is hard, the Home Soft+ stage adds a floorstanding resin cartridge in front of the unit so scale never reaches the cartridges or the element.
Will a softener make the water taste salty?
No. An ion-exchange softener swaps calcium and magnesium for a very small amount of sodium, far below the level you would taste. On a RoyalFlow build the drinking water then passes through the unit's own carbon filtration before it reaches the tap.
Hardness figures are compiled from the published supply-zone data of the UK water companies and are a guide to the typical range across a whole postcode area. Your own supplier’s postcode tool, linked beside every result above, is the authoritative figure for your address.