Hard water areas: published source reports
Browse areas with approved measured hardness above 200 mg/l as calcium carbonate. Coverage is incomplete and reporting periods differ, so this is not a ranking of the hardest places in the UK. Source-area names do not establish the supply to every address in a town.
DWI classifies more than 200 to 300 mg/l as hard, and more than 300 as very hard. Read the hardness guidance.
401 source areas have a measured value above 200 mg/l in our approved reports.
ALLINGTON
Wessex Water · Reporting period not retained in the cached source
327.7 mg/l · Very hard
Town pages: Allington
Amersham/Prestwood
Affinity Water · 2025
325 mg/l · Very hard
Town pages: Amersham, Amersham Common, Amersham Old Town and 27 more
ARN HILL
Wessex Water · Reporting period not retained in the cached source
287.3 mg/l · Hard
Town pages: Arn Hill
Ashford
Affinity Water · 2025
328 mg/l · Very hard
Town pages: Ashford, Surrey, Chattern Hill, Littleton, Surrey and 3 more
Bagshot/Sunninghill
Affinity Water · 2025
288 mg/l · Hard
Town pages: Blackwater, Bracknell, Camberley and 41 more
Baldock/Letchworth
Affinity Water · 2025
318 mg/l · Very hard
Town pages: Baldock, Biggleswade, Letchworth and 20 more
Barnet
Affinity Water · 2025
295 mg/l · Hard
Town pages: Arkley, Chipping Barnet, Ducks Island and 5 more
BATTERSEA SOUTH
Thames Water · 2024
255 mg/l · Hard
Town pages: Clapham Junction, Nine Elms, Sands End and 2 more
Beaconsfield/Chalfont St Giles
Affinity Water · 2025
288 mg/l · Hard
Town pages: Beaconsfield, Gerrards Cross, High Wycombe and 10 more
BERMONDSEY
Thames Water · 2025
257 mg/l · Hard
Town pages: Cubitt Town, Millwall, Shadwell, Greater London and 4 more
BEXLEY & BLACKFEN
Thames Water · 2024
284 mg/l · Hard
Town pages: Bowmans, Maypole, Old Bexley and 5 more
BEXLEYHEATH
Thames Water · 2024
359 mg/l · Very hard
Town pages: Barnehurst, Bexleyheath, Lessness Heath and 8 more
BICESTER
Thames Water · 2024
249 mg/l · Hard
Town pages: Bicester, Bicester Village, Bure Park and 6 more
Bishop Stortford
Affinity Water · 2025
345 mg/l · Very hard
Town pages: Bishop's Stortford, Hockerill, New Town, Hertfordshire and 16 more
BLACK LANE
Wessex Water · Reporting period not retained in the cached source
305.9 mg/l · Very hard
Town pages: Black Lane, South West England
Borehamwood/Bushey
Affinity Water · 2025
340 mg/l · Very hard
Town pages: Borehamwood, Elstree Park, Well End and 2 more
BOW
Thames Water · 2024
282 mg/l · Hard
Town pages: Blackwall, Bow Common, Bromley, Tower Hamlets and 17 more
BOWDEN
Wessex Water · Reporting period not retained in the cached source
353.7 mg/l · Very hard
Town pages: Bowden
BOWES PARK
Thames Water · 2024
258 mg/l · Hard
Town pages: Alexandra Park, Greater London, Bounds Green, Bowes Park and 4 more
BRENT CROSS
Thames Water · 2025
269 mg/l · Hard
Town pages: Acton Green, Brentford End, Grove Park, Hounslow and 3 more
BROMLEY TOWN
Thames Water · 2024
280 mg/l · Hard
Town pages: Bickley, Bromley Common, Bromley Park and 13 more
Bromsberrow
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
297 mg/l · Hard
Town pages: Cinderford, Mitcheldean, Hook Bank
Buntingford/Therfield
Affinity Water · 2025
375 mg/l · Very hard
Town pages: Buntingford, Newtown, Hertfordshire
BUSH HILL
Thames Water · 2024
269 mg/l · Hard
Town pages: Brimsdown, Bulls Cross, Enfield Highway and 4 more
Butterhill
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
352 mg/l · Very hard
Caddington/Eaton Bray
Affinity Water · 2025
348 mg/l · Very hard
Town pages: Churchend, Central Bedfordshire, Aley Green, Dagnall, Buckinghamshire and 5 more
CARTERTON
Thames Water · 2024
254 mg/l · Hard
Town pages: Burford, Carterton, Westhall Hill and 15 more
CASTLETON
Wessex Water · Reporting period not retained in the cached source
367.1 mg/l · Very hard
Town pages: Castleton, South West England
CHARLBURY OVERNORTON & WOODSTOCK
Thames Water · 2024
254 mg/l · Hard
Town pages: Charlbury, Woodstock, Church End, Oxfordshire and 2 more
CHARLTON
Wessex Water · Reporting period not retained in the cached source
306.9 mg/l · Very hard
Town pages: Charlton, South West England
Cheadle
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
212 mg/l · Hard
Town pages: Cheadle, Staffordshire
CHELSEA
Thames Water · 2025
259 mg/l · Hard
Town pages: Belgravia, Brompton, South Kensington and 2 more
CHIPPING CAMPDEN
Thames Water · 2024
276 mg/l · Hard
Town pages: Chipping Norton, Moreton-in-Marsh, Shipston-on-Stour and 1 more
CHIRTON
Wessex Water · Reporting period not retained in the cached source
320.4 mg/l · Very hard
Town pages: Chirton
CHISWICK & HAMMERSMITH
Thames Water · 2025
274 mg/l · Hard
Town pages: Bedford Park, Brook Green, East Acton and 5 more
CLAPHAM
Thames Water · 2025
255 mg/l · Hard
Town pages: Clapham Common, Clapham Park, Clapham and 1 more
Colindale/Kingsbury
Affinity Water · 2025
333 mg/l · Very hard
Town pages: Burnt Oak, Colindale, Grahame Park and 2 more
COMPTON
Wessex Water · Reporting period not retained in the cached source
246.6 mg/l · Hard
Town pages: Compton, South West England
COWLEY LITTLEMORE & NUNEHAM
Thames Water · 2024
276 mg/l · Hard
Town pages: Cowley Littlemore & Nuneham
CROYDON EAST
Thames Water · 2025
308 mg/l · Very hard
Town pages: Warlingham, Addiscombe, Bandonhill and 21 more
CRYSTAL PALACE & NORWOOD PARK
Thames Water · 2024
293 mg/l · Hard
Town pages: Crystal Palace & Norwood Park
DEWLISH DIRECT
Wessex Water · Reporting period not retained in the cached source
288.1 mg/l · Hard
Town pages: Dewlish Direct
DIDCOT
Thames Water · 2024
288 mg/l · Hard
Town pages: Didcot, Tadley, Oxfordshire, Appleford-on-Thames and 19 more
DORCHESTER
Wessex Water · Reporting period not retained in the cached source
296.4 mg/l · Hard
Town pages: Dorchester, Braytown, East Burton and 45 more
DULWICH
Thames Water · 2024
255 mg/l · Hard
Town pages: Dulwich, Dulwich Village, East Dulwich and 8 more
Dunstable
Affinity Water · 2025
310 mg/l · Very hard
Town pages: Dunstable, Houghton Regis, Leighton Buzzard and 1 more
Dursley
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
201 mg/l · Hard
Town pages: Dursley, Northleach, Nethercote and 21 more
EALING SOUTH
Thames Water · 2024
263 mg/l · Hard
Town pages: South Acton, Acton, Greater London, Ealing
East Barnet
Affinity Water · 2025
270 mg/l · Hard
Town pages: Cockfosters, East Barnet, Oakleigh Park and 3 more
East Leicester Rural
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
249 mg/l · Hard
Town pages: Melton Mowbray
ELTHAM PARK
Thames Water · 2024
274 mg/l · Hard
Town pages: Avery Hill, Falconwood, Mottingham and 3 more
ENFIELD SOUTH
Thames Water · 2024
265 mg/l · Hard
Town pages: Bush Hill Park, Grange Park, Winchmore Hill, Greater London
Epping/Ongar
Affinity Water · 2025
338 mg/l · Very hard
Town pages: Epping, Ivy Chimneys, Tyler's Green and 7 more
ESHER & CHESSINGTON
Thames Water · 2024
251 mg/l · Hard
Town pages: Esher, Effingham Common, Fairmile and 12 more
Feltham
Affinity Water · 2025
280 mg/l · Hard
Town pages: East Bedfont, Hanworth, Greater London, Hatton, Greater London and 3 more
Finchley
Affinity Water · 2025
275 mg/l · Hard
Town pages: Church End, Barnet, Coldfall, North Finchley and 3 more
FINMERE GODINGTON & LONG MARSTON
Thames Water · 2024
243 mg/l · Hard
Town pages: Finmere Godington & Long Marston
FIVEWAYS
Wessex Water · Reporting period not retained in the cached source
331.2 mg/l · Very hard
Town pages: Cranmore
Flamstead/Markyate
Affinity Water · 2025
333 mg/l · Very hard
Town pages: Flamstead, Jockey End, Kinsbourne Green and 4 more
Folkestone & Hythe
Affinity Water · 2025
285 mg/l · Hard
Town pages: Folkestone, Cheriton, Coolinge and 6 more
FORSTON
Wessex Water · Reporting period not retained in the cached source
284.5 mg/l · Hard
Town pages: Nunney
FOVANT
Wessex Water · Reporting period not retained in the cached source
306.1 mg/l · Very hard
Town pages: Darshill, Coxley Wick, Upper Coxley
GOFFS OAK
Thames Water · 2024
281 mg/l · Hard
Town pages: Flamstead End, Hammond Street, Rosedale and 7 more
GUILDFORD DISTRICT NORTH
Thames Water · 2024
287 mg/l · Hard
Town pages: Burpham, Cartbridge, Grove Heath and 15 more
GUILDFORD NORTH & SW
Thames Water · 2025
204 mg/l · Hard
Town pages: Guildford, Abbotswood, Bellfields and 8 more
HACKNEY WEST
Thames Water · 2024
280 mg/l · Hard
Town pages: Clapton Park, Dalston, Homerton and 8 more
HAMPSTEAD SOUTH
Thames Water · 2025
271 mg/l · Hard
Town pages: Childs Hill, Hampstead Heath, North End, Camden and 3 more
HARINGEY WEST
Thames Water · 2024
263 mg/l · Hard
Town pages: Cranley Gardens, Crouch End, Fortis Green and 5 more
Harlow North
Affinity Water · 2025
330 mg/l · Very hard
Town pages: Harlow, Eastend, Hare Street and 12 more
Harlow South
Affinity Water · 2025
310 mg/l · Very hard
Town pages: Brays Grove, Church Langley, Great Parndon and 16 more
Harpenden
Affinity Water · 2025
320 mg/l · Very hard
Town pages: Harpenden, Bamville Wood, Batford and 8 more
Harrow North
Affinity Water · 2025
360 mg/l · Very hard
Town pages: Greenhill, Greater London, Harrow Weald, Hatch End and 3 more
Hatfield/Potters Bar
Affinity Water · 2025
280 mg/l · Hard
Town pages: Hatfield, Birchwood, Hertfordshire, Bullen's Green and 19 more
Hayes
Affinity Water · 2025
265 mg/l · Hard
Town pages: Cranford, Harlington, Greater London, Hayes End and 2 more
Hemel Hempstead
Affinity Water · 2025
283 mg/l · Hard
Town pages: Hemel Hempstead, Adeyfield, Apsley and 20 more
Hemel/Kings Langley
Affinity Water · 2025
305 mg/l · Very hard
Town pages: Belsize, Chapel Croft, Nash Mills and 11 more
Hemel/Potten End
Affinity Water · 2025
320 mg/l · Very hard
Town pages: Great Gaddesden, Hudnall, Little Gaddesden and 3 more
HENDON & NEASDEN
Thames Water · 2025
261 mg/l · Hard
Town pages: Mill Hill, Greater London, Staples Corner, Welsh Harp and 2 more
Hertford
Affinity Water · 2025
318 mg/l · Very hard
Town pages: Hertford, Bengeo, Bayford, Hertfordshire and 9 more
HEYTESBURY
Wessex Water · Reporting period not retained in the cached source
262.9 mg/l · Hard
Town pages: Heytesbury
HIGHAMS PARK
Thames Water · 2024
275 mg/l · Hard
Town pages: Chingford Green, Chingford Hatch, Friday Hill and 4 more
HIGHBURY
Thames Water · 2024
259 mg/l · Hard
Town pages: Brownswood Park, Canonbury, De Beauvoir Town and 3 more
Hinckley
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
204 mg/l · Hard
Hitchin
Affinity Water · 2025
368 mg/l · Very hard
Town pages: Hitchin, Shefford, Bury End, Central Bedfordshire and 28 more
HODDESDON
Thames Water · 2024
278 mg/l · Hard
Town pages: Hoddesdon, Broxbourne, Dobb's Weir and 10 more
HOLT
Wessex Water · Reporting period not retained in the cached source
362.8 mg/l · Very hard
Town pages: Holt
HOOKE
Wessex Water · Reporting period not retained in the cached source
314 mg/l · Very hard
Town pages: Hooke
HOUNSLOW HEATH
Thames Water · 2024
263 mg/l · Hard
Town pages: Hounslow West, Lampton, Osterley and 4 more
KENSINGTON SOUTH
Thames Water · 2024
257 mg/l · Hard
Town pages: Earl's Court, Notting Hill, Kensington (Kensington South supply area)
KENTISH TOWN
Thames Water · 2024
263 mg/l · Hard
Town pages: Dartmouth Park, Gospel Oak, Kentish Town and 4 more
KINGS CROSS
Thames Water · 2024
262 mg/l · Hard
Town pages: Berrylands, Coombe, Greater London, Hampton Wick and 8 more
Knebworth/Tewin
Affinity Water · 2025
295 mg/l · Hard
Town pages: Bragbury End, Broadwater, Aston, Hertfordshire and 9 more
LAMBETH SOUTH
Thames Water · 2024
257 mg/l · Hard
Town pages: Kennington, Newington, Greater London, Pimlico, Greater London and 3 more
Leamington
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
304 mg/l · Very hard
Town pages: Royal Leamington Spa, Bridge Town, Clopton and 49 more
LEWISHAM SOUTH
Thames Water · 2024
279 mg/l · Hard
Town pages: Blackheath Park, Brockley, Hither Green and 8 more
LITTON CHENEY
Wessex Water · Reporting period not retained in the cached source
283 mg/l · Hard
Town pages: Litton Cheney
Luton North
Affinity Water · 2025
288 mg/l · Hard
Town pages: Flitwick, Biscot, Bramingham Park and 19 more
Luton Park Street
Affinity Water · 2025
328 mg/l · Very hard
Town pages: Luton, Hart Hill, New Town, Luton and 2 more
Luton Stopsley
Affinity Water · 2025
345 mg/l · Very hard
Town pages: Perry Green, North Hertfordshire, Stopsley, Wigmore and 2 more
Luton West/Houghton Regis
Affinity Water · 2025
308 mg/l · Very hard
Town pages: Bury Park, Farley Hill, Farleygreen and 3 more
Lydbrook
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
335 mg/l · Very hard
Town pages: Clements End, Christchurch, Gloucestershire
Mansfield
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
303 mg/l · Very hard
Town pages: Mansfield, Bleak Hills, Ladybrook and 4 more
MARYLEBONE & PADDINGTON
Thames Water · 2025
273 mg/l · Hard
Town pages: Bayswater, Kensal Town, Maida Vale and 4 more
MERE
Wessex Water · Reporting period not retained in the cached source
275.1 mg/l · Hard
Town pages: Gillingham, Mere, Shaftesbury and 25 more
MILBORNE ST ANDREW
Wessex Water · Reporting period not retained in the cached source
298.5 mg/l · Hard
Town pages: Milborne St Andrew, South West England
MILBOURNE
Wessex Water · Reporting period not retained in the cached source
317 mg/l · Very hard
Town pages: Milbourne
MITCHAM
Thames Water · 2024
262 mg/l · Hard
Town pages: Beddington Corner, Hackbridge, Lower Morden and 7 more
Mixed Zone
Affinity Water · 2025
305 mg/l · Very hard
Town pages: Black Green, Smug Oak, Chiswell Green and 5 more
MOLESEY
Thames Water · 2025
256 mg/l · Hard
Town pages: East Molesey, Thames Ditton, West Molesey and 1 more
MUSWELL HILL & HAMPSTEAD HEATH
Thames Water · 2025
263 mg/l · Hard
Town pages: Muswell Hill & Hampstead Heath
Newark
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
206 mg/l · Hard
Town pages: Newark-on-Trent, Southwell, Beacon Hill and 11 more
Northwood
Affinity Water · 2025
348 mg/l · Very hard
Town pages: Carpenders Park, Northwood Hills, Pinner Green and 6 more
Nottingham City
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
227 mg/l · Hard
Town pages: Nottingham, Alexandra Park, Nottingham, Bakersfield and 13 more
Nuneaton North
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
203 mg/l · Hard
Town pages: Nuneaton
Nuneaton South
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
220 mg/l · Hard
Town pages: Ansley Common, Bedworth
Offley/Kimpton
Affinity Water · 2025
338 mg/l · Very hard
Town pages: Breachwood Green, Great Offley, Lilley and 2 more
ORPINGTON
Thames Water · 2025
291 mg/l · Hard
Town pages: Westerham, Bessels Green, Broom Hill and 16 more
OXFORD CENTRAL
Thames Water · 2024
255 mg/l · Hard
Town pages: Kidlington, Cutteslowe, Garden City and 15 more
OXFORD EAST
Thames Water · 2024
276 mg/l · Hard
Town pages: Oxford, Barton, Oxfordshire, Blackbird Leys and 18 more
OXFORD WEST & KIDLINGTON
Thames Water · 2024
246 mg/l · Hard
Town pages: Botley, Cumnor Hill, Dean Court and 18 more
Paddlesworth
Affinity Water · 2025
293 mg/l · Hard
Town pages: Hythe, North Lyminge, Orchard Valley and 18 more
PARLIAMENT
Thames Water · 2025
264 mg/l · Hard
Town pages: Westminster, Hyde Park Corner, Mayfair and 2 more
PENTONVILLE
Thames Water · 2024
260 mg/l · Hard
Town pages: Clerkenwell, Finsbury, King's Cross and 3 more
Pilgrims Hatch
Affinity Water · 2025
265 mg/l · Hard
Town pages: Basildon, Billericay, Brentwood and 1 more
Pirbright/Send
Affinity Water · 2025
288 mg/l · Hard
Town pages: Farnborough, Farnborough Park, Farnborough Street and 16 more
PLUMSTEAD
Thames Water · 2024
341 mg/l · Very hard
Town pages: Beckton, Bostall Woods, Cyprus, Greater London and 10 more
POOLE TOWN
Wessex Water · Reporting period not retained in the cached source
295.4 mg/l · Hard
Town pages: Bournemouth, Christchurch, Ferndown and 3 more
Potters Bar West
Affinity Water · 2025
363 mg/l · Very hard
Town pages: Potters Bar, Bell Bar, Little Heath, Hertfordshire and 2 more
PURBECK
Wessex Water · Reporting period not retained in the cached source
305.4 mg/l · Very hard
Town pages: Marston Gate
PUTNEY HEATH
Thames Water · 2024
257 mg/l · Hard
Town pages: Parsons Green, Putney Heath, Putney Vale and 4 more
Rayners Lane
Affinity Water · 2025
268 mg/l · Hard
Town pages: North Harrow, Rayners Lane, South Harrow and 2 more
READING WEST
Thames Water · 2024
315 mg/l · Very hard
Town pages: Caversham Heights, Coley, Hemdean Bottom and 8 more
RICHMOND
Thames Water · 2024
251 mg/l · Hard
Town pages: East Sheen, Kew, Greater London, Mortlake and 5 more
Rickmansworth/Gerrards Cross
Affinity Water · 2025
283 mg/l · Hard
Town pages: Chorleywood, Rickmansworth, Batchworth and 14 more
RODING VALLEY
Thames Water · 2024
275 mg/l · Hard
Town pages: Chigwell, Loughton, Collier Row and 11 more
Ruislip
Affinity Water · 2025
320 mg/l · Very hard
Town pages: Eastcote, Ruislip Common, Ruislip Manor and 2 more
Saffron Walden
Affinity Water · 2025
360 mg/l · Very hard
Town pages: Saffron Walden, Little Walden, Littlebury and 1 more
Sawbridgeworth
Affinity Water · 2025
340 mg/l · Very hard
Town pages: Sawbridgeworth, Churchgate Street, Lower Sheering and 1 more
SHAFTESBURY
Wessex Water · Reporting period not retained in the cached source
288.5 mg/l · Hard
Town pages: Shepton Mallet, Charlton, Somerset, East Town and 13 more
SHEPHERDS SHORE
Wessex Water · Reporting period not retained in the cached source
342.2 mg/l · Very hard
Town pages: Shepherds Shore
SIDCUP & ELMSTEAD WOOD
Thames Water · 2024
331 mg/l · Very hard
Town pages: Blackfen, Chislehurst West, Foots Cray and 4 more
South East Leicester
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
247 mg/l · Hard
Town pages: Leicester, Syston, Beaumont Leys and 41 more
Southall
Affinity Water · 2025
280 mg/l · Hard
Town pages: Dormer's Wells, North Hyde, Norwood Green, Greater London and 1 more
SOUTHGATE
Thames Water · 2024
265 mg/l · Hard
Town pages: Brunswick Park, New Southgate, Oakwood, Greater London and 2 more
Southport Central
United Utilities · Rolling 12 months; updated 2026-10-02
254 mg/l · Hard
Town pages: Southport
St Albans North
Affinity Water · 2025
338 mg/l · Very hard
Town pages: Bernards Heath, Fleetville, Jersey Farm and 4 more
St Albans South
Affinity Water · 2025
338 mg/l · Very hard
Town pages: St Albans, Sopwell, St Julians and 4 more
ST JOHNS WOOD & MAYFAIR
Thames Water · 2025
271 mg/l · Hard
Town pages: Lisson Grove, South Hampstead, St John's Wood
Staines
Affinity Water · 2025
295 mg/l · Hard
Town pages: Egham, Staines-upon-Thames, Birch Green, Surrey and 24 more
Standon
Affinity Water · 2025
330 mg/l · Very hard
Town pages: Church End, East Hertfordshire, Green End, East Hertfordshire, Colliers End
Stanmore/Mill Hill
Affinity Water · 2025
353 mg/l · Very hard
Town pages: Belmont, Harrow, Canons Park, Little Stanmore and 2 more
STOCKLINCH
Wessex Water · Reporting period not retained in the cached source
267.3 mg/l · Hard
Town pages: Downside
STRATFORD EAST
Thames Water · 2024
277 mg/l · Hard
Town pages: Custom House, Forest Gate, Hackney Marsh and 10 more
STREATHAM NORTH
Thames Water · 2024
274 mg/l · Hard
Town pages: Streatham Hill, Streatham Park, Streatham
STREATHAM SOUTH & DULWICH WEST
Thames Water · 2024
264 mg/l · Hard
Town pages: Streatham South & Dulwich West
Sudbury
Affinity Water · 2025
290 mg/l · Hard
Town pages: North Wembley, Perivale, Sudbury, Greater London
SUNBURY EAST
Thames Water · 2024
253 mg/l · Hard
Town pages: Sunbury-on-Thames, Felthamhill, Kempton Park and 4 more
Surface Zone
Affinity Water · 2025
228 mg/l · Hard
Town pages: Garston, Kingswood, Hertfordshire, Leavesden Green and 3 more
SWANAGE
Wessex Water · Reporting period not retained in the cached source
274.4 mg/l · Hard
Town pages: Swanage, Coombe, Dorset, Durlston and 16 more
SWINDON NORTH
Thames Water · 2025
271 mg/l · Hard
Town pages: Abbey Meads, Ash Brake, Gorse Hill, Swindon and 23 more
TEDDINGTON
Thames Water · 2024
259 mg/l · Hard
Town pages: Ham, Greater London, Hampton Court, Hampton Hill and 2 more
THAMESMEAD
Thames Water · 2024
342 mg/l · Very hard
Town pages: Barking Riverside, Becontree, Becontree Heath and 13 more
TILEHURST VILLAGE
Thames Water · 2024
309 mg/l · Very hard
Town pages: Burghfield Hill, Calcot, Calcot Row and 24 more
TOTTENHAM SOUTH
Thames Water · 2024
268 mg/l · Hard
Town pages: Craven Walk, South Tottenham, Tottenham Hale and 2 more
TROWBRIDGE
Wessex Water · Reporting period not retained in the cached source
276.8 mg/l · Hard
Town pages: Bradford-on-Avon, Devizes, Melksham and 22 more
TWYFORD WARGRAVE & SONNING
Thames Water · 2025
346 mg/l · Very hard
Town pages: Twyford Wargrave & Sonning
Underground 1 Zone
Affinity Water · 2025
360 mg/l · Very hard
Town pages: Radlett, Battlers Green, The Folly, Hertsmere and 2 more
Underground 2 Zone
Affinity Water · 2025
313 mg/l · Very hard
Town pages: Bushey, Bushey Heath, Patchetts Green
UPTON SCUDAMORE
Wessex Water · Reporting period not retained in the cached source
322.7 mg/l · Very hard
Town pages: Upton Scudamore
Uxbridge
Affinity Water · 2025
308 mg/l · Very hard
Town pages: Cowley, Greater London, Denham Green, North Hillingdon and 11 more
WALL END
Thames Water · 2024
268 mg/l · Hard
Town pages: Wallingford, Bridge End, Oxfordshire, Cleeve and 30 more
WALTHAM ABBEY
Thames Water · 2024
269 mg/l · Hard
Town pages: Waltham Abbey, Enfield Island Village, Enfield Lock and 3 more
WALTHAMSTOW
Thames Water · 2024
278 mg/l · Hard
Town pages: Higham Hill, Upper Walthamstow, Central Parade and 2 more
Walton
Affinity Water · 2025
288 mg/l · Hard
Town pages: Walton-on-Thames, Ash Estates, Ashley Park and 5 more
WANDSWORTH WANDLE
Thames Water · 2025
265 mg/l · Hard
Town pages: Wandsworth Common, The Mews, Wandsworth
WANSTEAD PARK
Thames Water · 2024
265 mg/l · Hard
Town pages: Aldborough Hatch, Barkingside, Chadwell Heath and 12 more
WANTAGE EAST
Thames Water · 2024
296 mg/l · Hard
Town pages: Wantage, Belmont, Oxfordshire, Charlton, Oxfordshire and 2 more
Watford North
Affinity Water · 2025
323 mg/l · Very hard
Town pages: Meriden, North Watford, Chandler's Cross
Watford South
Affinity Water · 2025
353 mg/l · Very hard
Town pages: Watford, Holywell, Hertfordshire, Oxhey and 3 more
Welwyn Garden City
Affinity Water · 2025
320 mg/l · Very hard
Town pages: Welwyn Garden City, Digswell, Digswell Park and 13 more
Wembley
Affinity Water · 2025
295 mg/l · Hard
Town pages: Alperton, Preston, Greater London, Stonebridge, Greater London and 3 more
West Drayton
Affinity Water · 2025
283 mg/l · Hard
Town pages: Colham Green, Cowley Peachey, Harmondsworth and 13 more
Weybridge/Woodham
Affinity Water · 2025
255 mg/l · Hard
Town pages: Addlestone, Chertsey, Weybridge and 19 more
WEYMOUTH
Wessex Water · Reporting period not retained in the cached source
284.5 mg/l · Hard
Town pages: Chickerell, Fortuneswell, Weymouth and 36 more
WHITECHAPEL
Thames Water · 2024
270 mg/l · Hard
Town pages: Globe Town (Whitechapel supply area), Haggerston, Limehouse and 6 more
Widnes West
United Utilities · Rolling 12 months; updated 2026-09-04
225 mg/l · Hard
Town pages: Widnes
WILLESDEN
Thames Water · 2024
259 mg/l · Hard
Town pages: Brondesbury Park, Church End, Brent, College Park and 8 more
WIMBLEDON
Thames Water · 2024
260 mg/l · Hard
Town pages: Bushey Mead, Collier's Wood, Copse Hill and 7 more
WINDSOR & COLNBROOK
Thames Water · 2024
301 mg/l · Very hard
Town pages: Eton, Maidenhead, Slough and 1 more
Woking
Affinity Water · 2025
273 mg/l · Hard
Town pages: Woking, Hockering Estate, Hook Heath and 16 more
Wollaton
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
221 mg/l · Hard
Town pages: Ilkeston, Stapleford, Aspley, Nottingham and 11 more
WOODFORD
Thames Water · 2024
278 mg/l · Hard
Town pages: South Woodford, Woodford Bridge, Woodford Green and 2 more
Wotton
Severn Trent Water · Rolling report 2025-08-01 to 2026-07-31; hardness period not stated
272 mg/l · Hard
Town pages: Minchinhampton, Nailsworth, Painswick and 3 more
WYCOMBE SOUTH NORTH & CENTRAL
Thames Water · 2025
298 mg/l · Hard
Town pages: Wycombe South North & Central