Water Hardness in Greater London

London • 330 postcode districts • 13 towns

Hard

286

Average ppm

150

Minimum ppm

350

Maximum ppm

330

Postcodes

Water Hardness Across Greater London

The average water hardness in Greater London is 286 ppm, classified as hard. Across 330 postcode districts in the London region, hardness ranges from 150 ppm to 350 ppm.

Greater London is served by Affinity Water and SES Water and Severn Trent Water and South East Water and Thames Water and Yorkshire Water. With hard water, residents may benefit from a <a href="/water-softener-guide/">water softener</a> to reduce limescale and protect appliances.

Towns in Greater London

Town	Avg Hardness	PPM	Level
Wembley	332 ppm	332 ppm	Very Hard
Enfield	325 ppm	325 ppm	Very Hard
Romford	318 ppm	318 ppm	Very Hard
Ilford	310 ppm	310 ppm	Very Hard
Kingston Upon Thames	310 ppm	310 ppm	Very Hard
London	306 ppm	306 ppm	Very Hard
Bromley	297 ppm	297 ppm	Hard
Croydon	297 ppm	297 ppm	Hard
Dartford	289 ppm	289 ppm	Hard
Southall	287 ppm	287 ppm	Hard
Twickenham	284 ppm	284 ppm	Hard
Sutton	239 ppm	239 ppm	Hard
Watford	233 ppm	233 ppm	Hard

Water Companies in Greater London

Affinity Water

Average: 268 ppm (Hard)

SES Water

Average: 239 ppm (Hard)

Severn Trent Water

Average: 222 ppm (Hard)

South East Water

Average: 297 ppm (Hard)

Thames Water

Average: 302 ppm (Very Hard)

Yorkshire Water

Average: 215 ppm (Hard)

All Postcodes in Greater London

Postcode	Town	Hardness	PPM	Level
E7	London	350 ppm	350 ppm	Very Hard
E6	London	349 ppm	349 ppm	Very Hard
E5	London	348 ppm	348 ppm	Very Hard
E4	London	347 ppm	347 ppm	Very Hard
E3	London	346 ppm	346 ppm	Very Hard
EN9	Waltham Abbey	346 ppm	346 ppm	Very Hard
KT24	Leatherhead	346 ppm	346 ppm	Very Hard
N9	London	346 ppm	346 ppm	Very Hard
E2	London	345 ppm	345 ppm	Very Hard
EN8	Waltham Cross	345 ppm	345 ppm	Very Hard
KT23	Leatherhead	345 ppm	345 ppm	Very Hard
N8	London	345 ppm	345 ppm	Very Hard
E1	London	344 ppm	344 ppm	Very Hard
EN7	Waltham Cross	344 ppm	344 ppm	Very Hard
KT22	Leatherhead	344 ppm	344 ppm	Very Hard
N7	London	344 ppm	344 ppm	Very Hard
EN6	Potters Bar	343 ppm	343 ppm	Very Hard
KT21	Ashtead	343 ppm	343 ppm	Very Hard
N6	London	343 ppm	343 ppm	Very Hard
EC2A	London	342 ppm	342 ppm	Very Hard
EN5	Barnet	342 ppm	342 ppm	Very Hard
KT20	Tadworth	342 ppm	342 ppm	Very Hard
N5	London	342 ppm	342 ppm	Very Hard
EN4	Barnet	341 ppm	341 ppm	Very Hard
N4	London	341 ppm	341 ppm	Very Hard
EN3	Enfield	340 ppm	340 ppm	Very Hard
N3	London	340 ppm	340 ppm	Very Hard
W9	London	340 ppm	340 ppm	Very Hard
EN2	Enfield	339 ppm	339 ppm	Very Hard
N2	London	339 ppm	339 ppm	Very Hard
RM19	Purfleet On Thames	339 ppm	339 ppm	Very Hard
W8	London	339 ppm	339 ppm	Very Hard
EN1	Enfield	338 ppm	338 ppm	Very Hard
N1	London	338 ppm	338 ppm	Very Hard
RM18	Tilbury	338 ppm	338 ppm	Very Hard
W7	London	338 ppm	338 ppm	Very Hard
RM17	Grays	337 ppm	337 ppm	Very Hard
W6	London	337 ppm	337 ppm	Very Hard
HA9	Wembley	336 ppm	336 ppm	Very Hard
RM16	Grays	336 ppm	336 ppm	Very Hard
W5	London	336 ppm	336 ppm	Very Hard
HA8	Edgware	335 ppm	335 ppm	Very Hard
RM15	South Ockendon	335 ppm	335 ppm	Very Hard
W4	London	335 ppm	335 ppm	Very Hard
HA7	Stanmore	334 ppm	334 ppm	Very Hard
RM14	Upminster	334 ppm	334 ppm	Very Hard
SW1Y	London	334 ppm	334 ppm	Very Hard
W3	London	334 ppm	334 ppm	Very Hard
EC1Y	London	333 ppm	333 ppm	Very Hard
HA6	Northwood	333 ppm	333 ppm	Very Hard
RM13	Rainham	333 ppm	333 ppm	Very Hard
SW1X	London	333 ppm	333 ppm	Very Hard
W2	London	333 ppm	333 ppm	Very Hard
HA5	Pinner	332 ppm	332 ppm	Very Hard
RM12	Hornchurch	332 ppm	332 ppm	Very Hard
SW1W	London	332 ppm	332 ppm	Very Hard
EC4Y	London	331 ppm	331 ppm	Very Hard
HA4	Ruislip	331 ppm	331 ppm	Very Hard
IG11	Barking	331 ppm	331 ppm	Very Hard
RM11	Hornchurch	331 ppm	331 ppm	Very Hard
SW1V	London	331 ppm	331 ppm	Very Hard
EC1V	London	330 ppm	330 ppm	Very Hard
HA3	Harrow	330 ppm	330 ppm	Very Hard
IG10	Loughton	330 ppm	330 ppm	Very Hard
RM10	Dagenham	330 ppm	330 ppm	Very Hard
HA2	Harrow	329 ppm	329 ppm	Very Hard
EC4V	London	328 ppm	328 ppm	Very Hard
HA1	Harrow	328 ppm	328 ppm	Very Hard
HA0	Wembley	327 ppm	327 ppm	Very Hard
SE9	London	327 ppm	327 ppm	Very Hard
EC1R	London	326 ppm	326 ppm	Very Hard
SE28	London	326 ppm	326 ppm	Very Hard
SE8	London	326 ppm	326 ppm	Very Hard
SW20	London	326 ppm	326 ppm	Very Hard
SE27	London	325 ppm	325 ppm	Very Hard
SE7	London	325 ppm	325 ppm	Very Hard
SW1P	London	325 ppm	325 ppm	Very Hard
EC4R	London	324 ppm	324 ppm	Very Hard
NW9	London	324 ppm	324 ppm	Very Hard
SE26	London	324 ppm	324 ppm	Very Hard
SE6	London	324 ppm	324 ppm	Very Hard
DA9	Greenhithe	323 ppm	323 ppm	Very Hard
NW8	London	323 ppm	323 ppm	Very Hard
SE25	London	323 ppm	323 ppm	Very Hard
SE5	London	323 ppm	323 ppm	Very Hard
DA8	Erith	322 ppm	322 ppm	Very Hard
EC1N	London	322 ppm	322 ppm	Very Hard
NW7	London	322 ppm	322 ppm	Very Hard
SE24	London	322 ppm	322 ppm	Very Hard
SE4	London	322 ppm	322 ppm	Very Hard
DA7	Bexleyheath	321 ppm	321 ppm	Very Hard
EC1M	London	321 ppm	321 ppm	Very Hard
NW6	London	321 ppm	321 ppm	Very Hard
SE23	London	321 ppm	321 ppm	Very Hard
SE3	London	321 ppm	321 ppm	Very Hard
DA6	Bexleyheath	320 ppm	320 ppm	Very Hard
EC4N	London	320 ppm	320 ppm	Very Hard
NW5	London	320 ppm	320 ppm	Very Hard
SE2	London	320 ppm	320 ppm	Very Hard
SE22	London	320 ppm	320 ppm	Very Hard
WC2R	London	320 ppm	320 ppm	Very Hard
DA5	Bexley	319 ppm	319 ppm	Very Hard
EC4M	London	319 ppm	319 ppm	Very Hard
NW4	London	319 ppm	319 ppm	Very Hard
SE1	London	319 ppm	319 ppm	Very Hard
SE21	London	319 ppm	319 ppm	Very Hard
DA4	Dartford	318 ppm	318 ppm	Very Hard
KT19	Epsom	318 ppm	318 ppm	Very Hard
NW3	London	318 ppm	318 ppm	Very Hard
SE20	London	318 ppm	318 ppm	Very Hard
DA3	Longfield	317 ppm	317 ppm	Very Hard
KT18	Epsom	317 ppm	317 ppm	Very Hard
NW2	London	317 ppm	317 ppm	Very Hard
SW1H	London	317 ppm	317 ppm	Very Hard
DA2	Dartford	316 ppm	316 ppm	Very Hard
KT17	Epsom	316 ppm	316 ppm	Very Hard
NW1	London	316 ppm	316 ppm	Very Hard
W1W	London	316 ppm	316 ppm	Very Hard
WC2N	London	316 ppm	316 ppm	Very Hard
DA1	Dartford	315 ppm	315 ppm	Very Hard
KT16	Chertsey	315 ppm	315 ppm	Very Hard
SW9	London	315 ppm	315 ppm	Very Hard
KT15	Addlestone	314 ppm	314 ppm	Very Hard
SW1E	London	314 ppm	314 ppm	Very Hard
SW8	London	314 ppm	314 ppm	Very Hard
UB11	Uxbridge	314 ppm	314 ppm	Very Hard
W1U	London	314 ppm	314 ppm	Very Hard
KT14	West Byfleet	313 ppm	313 ppm	Very Hard
SW7	London	313 ppm	313 ppm	Very Hard
UB10	Uxbridge	313 ppm	313 ppm	Very Hard
W1T	London	313 ppm	313 ppm	Very Hard
KT13	Weybridge	312 ppm	312 ppm	Very Hard
SW6	London	312 ppm	312 ppm	Very Hard
W1S	London	312 ppm	312 ppm	Very Hard
KT12	Walton On Thames	311 ppm	311 ppm	Very Hard
SW5	London	311 ppm	311 ppm	Very Hard
IG9	Buckhurst Hill	310 ppm	310 ppm	Very Hard
KT11	Cobham	310 ppm	310 ppm	Very Hard
RM9	Dagenham	310 ppm	310 ppm	Very Hard
SW1A	London	310 ppm	310 ppm	Very Hard
SW4	London	310 ppm	310 ppm	Very Hard
WC2H	London	310 ppm	310 ppm	Very Hard
EC1A	London	309 ppm	309 ppm	Very Hard
IG8	Woodford Green	309 ppm	309 ppm	Very Hard
KT10	Esher	309 ppm	309 ppm	Very Hard
RM8	Dagenham	309 ppm	309 ppm	Very Hard
SW3	London	309 ppm	309 ppm	Very Hard
E1W	London	308 ppm	308 ppm	Very Hard
IG7	Chigwell	308 ppm	308 ppm	Very Hard
N22	London	308 ppm	308 ppm	Very Hard
RM7	Romford	308 ppm	308 ppm	Very Hard
SW2	London	308 ppm	308 ppm	Very Hard
EC4A	London	307 ppm	307 ppm	Very Hard
IG6	Ilford	307 ppm	307 ppm	Very Hard
N21	London	307 ppm	307 ppm	Very Hard
RM6	Romford	307 ppm	307 ppm	Very Hard
TW20	Egham	307 ppm	307 ppm	Very Hard
WC2E	London	307 ppm	307 ppm	Very Hard
IG5	Ilford	306 ppm	306 ppm	Very Hard
N20	London	306 ppm	306 ppm	Very Hard
RM5	Romford	306 ppm	306 ppm	Very Hard
IG4	Ilford	305 ppm	305 ppm	Very Hard
RM4	Romford	305 ppm	305 ppm	Very Hard
IG3	Ilford	304 ppm	304 ppm	Very Hard
RM3	Romford	304 ppm	304 ppm	Very Hard
W1K	London	304 ppm	304 ppm	Very Hard
WC2B	London	304 ppm	304 ppm	Very Hard
IG2	Ilford	303 ppm	303 ppm	Very Hard
RM2	Romford	303 ppm	303 ppm	Very Hard
W1J	London	303 ppm	303 ppm	Very Hard
WC2A	London	303 ppm	303 ppm	Very Hard
E20	Olympic Park	302 ppm	302 ppm	Very Hard
IG1	Ilford	302 ppm	302 ppm	Very Hard
RM1	Romford	302 ppm	302 ppm	Very Hard
SW19	London	302 ppm	302 ppm	Very Hard
CR9	Croydon	301 ppm	301 ppm	Very Hard
SW18	London	301 ppm	301 ppm	Very Hard
W1H	London	301 ppm	301 ppm	Very Hard
BR8	Swanley	300 ppm	300 ppm	Hard
CR8	Purley	300 ppm	300 ppm	Hard
SW17	London	300 ppm	300 ppm	Hard
W1G	London	300 ppm	300 ppm	Hard
BR7	Chislehurst	299 ppm	299 ppm	Hard
CR7	Thornton Heath	299 ppm	299 ppm	Hard
SW16	London	299 ppm	299 ppm	Hard
W1F	London	299 ppm	299 ppm	Hard
BR6	Orpington	298 ppm	298 ppm	Hard
CR6	Warlingham	298 ppm	298 ppm	Hard
SW15	London	298 ppm	298 ppm	Hard
BR5	Orpington	297 ppm	297 ppm	Hard
CR5	Coulsdon	297 ppm	297 ppm	Hard
SW14	London	297 ppm	297 ppm	Hard
W1D	London	297 ppm	297 ppm	Hard
BR4	West Wickham	296 ppm	296 ppm	Hard
CR4	Mitcham	296 ppm	296 ppm	Hard
SW13	London	296 ppm	296 ppm	Hard
W1C	London	296 ppm	296 ppm	Hard
BR3	Beckenham	295 ppm	295 ppm	Hard
CR3	Caterham	295 ppm	295 ppm	Hard
EC3V	London	295 ppm	295 ppm	Hard
SW12	London	295 ppm	295 ppm	Hard
W1B	London	295 ppm	295 ppm	Hard
BR2	Bromley	294 ppm	294 ppm	Hard
CR2	South Croydon	294 ppm	294 ppm	Hard
SE19	London	294 ppm	294 ppm	Hard
SW11	London	294 ppm	294 ppm	Hard
BR1	Bromley	293 ppm	293 ppm	Hard
SE18	London	293 ppm	293 ppm	Hard
SW10	London	293 ppm	293 ppm	Hard
TW9	Richmond	293 ppm	293 ppm	Hard
WC1X	London	293 ppm	293 ppm	Hard
CR0	Croydon	292 ppm	292 ppm	Hard
N1C	London	292 ppm	292 ppm	Hard
SE17	London	292 ppm	292 ppm	Hard
TW8	Brentford	292 ppm	292 ppm	Hard
EC3R	London	291 ppm	291 ppm	Hard
KT9	Chessington	291 ppm	291 ppm	Hard
SE16	London	291 ppm	291 ppm	Hard
TW7	Isleworth	291 ppm	291 ppm	Hard
WC1V	London	291 ppm	291 ppm	Hard
KT8	West Molesey	290 ppm	290 ppm	Hard
SE15	London	290 ppm	290 ppm	Hard
KT7	Thames Ditton	289 ppm	289 ppm	Hard
SE14	London	289 ppm	289 ppm	Hard
TW5	Hounslow	289 ppm	289 ppm	Hard
KT6	Surbiton	288 ppm	288 ppm	Hard
NW11	London	288 ppm	288 ppm	Hard
SE13	London	288 ppm	288 ppm	Hard
TW4	Hounslow	288 ppm	288 ppm	Hard
EC3N	London	287 ppm	287 ppm	Hard
KT5	Surbiton	287 ppm	287 ppm	Hard
NW10	London	287 ppm	287 ppm	Hard
SE12	London	287 ppm	287 ppm	Hard
TW3	Hounslow	287 ppm	287 ppm	Hard
WC1R	London	287 ppm	287 ppm	Hard
EC3M	London	286 ppm	286 ppm	Hard
KT4	Worcester Park	286 ppm	286 ppm	Hard
SE11	London	286 ppm	286 ppm	Hard
TW2	Twickenham	286 ppm	286 ppm	Hard
KT3	New Malden	285 ppm	285 ppm	Hard
SE10	London	285 ppm	285 ppm	Hard
TW1	Twickenham	285 ppm	285 ppm	Hard
UB9	Uxbridge	285 ppm	285 ppm	Hard
KT2	Kingston Upon Thames	284 ppm	284 ppm	Hard
UB8	Uxbridge	284 ppm	284 ppm	Hard
KT1	Kingston Upon Thames	283 ppm	283 ppm	Hard
TW19	Staines Upon Thames	283 ppm	283 ppm	Hard
UB7	West Drayton	283 ppm	283 ppm	Hard
WC1N	London	283 ppm	283 ppm	Hard
N19	London	282 ppm	282 ppm	Hard
TW18	Staines Upon Thames	282 ppm	282 ppm	Hard
UB6	Greenford	282 ppm	282 ppm	Hard
N18	London	281 ppm	281 ppm	Hard
TW17	Shepperton	281 ppm	281 ppm	Hard
UB5	Northolt	281 ppm	281 ppm	Hard
W14	London	281 ppm	281 ppm	Hard
N17	London	280 ppm	280 ppm	Hard
TW16	Sunbury On Thames	280 ppm	280 ppm	Hard
UB4	Hayes	280 ppm	280 ppm	Hard
W13	London	280 ppm	280 ppm	Hard
N16	London	279 ppm	279 ppm	Hard
TW15	Ashford	279 ppm	279 ppm	Hard
UB3	Hayes	279 ppm	279 ppm	Hard
W12	London	279 ppm	279 ppm	Hard
N15	London	278 ppm	278 ppm	Hard
TW14	Feltham	278 ppm	278 ppm	Hard
UB2	Southall	278 ppm	278 ppm	Hard
W11	London	278 ppm	278 ppm	Hard
E18	London	277 ppm	277 ppm	Hard
N14	London	277 ppm	277 ppm	Hard
TW13	Feltham	277 ppm	277 ppm	Hard
UB1	Southall	277 ppm	277 ppm	Hard
W10	London	277 ppm	277 ppm	Hard
WC1H	London	277 ppm	277 ppm	Hard
E17	London	276 ppm	276 ppm	Hard
N13	London	276 ppm	276 ppm	Hard
TW12	Hampton	276 ppm	276 ppm	Hard
E16	London	275 ppm	275 ppm	Hard
N12	London	275 ppm	275 ppm	Hard
TW11	Teddington	275 ppm	275 ppm	Hard
E15	London	274 ppm	274 ppm	Hard
EC3A	London	274 ppm	274 ppm	Hard
N11	London	274 ppm	274 ppm	Hard
TW10	Richmond	274 ppm	274 ppm	Hard
WC1E	London	274 ppm	274 ppm	Hard
E14	London	273 ppm	273 ppm	Hard
N10	London	273 ppm	273 ppm	Hard
E13	London	272 ppm	272 ppm	Hard
E12	London	271 ppm	271 ppm	Hard
WC1B	London	271 ppm	271 ppm	Hard
E11	London	270 ppm	270 ppm	Hard
WC1A	London	270 ppm	270 ppm	Hard
E10	London	269 ppm	269 ppm	Hard
EC2Y	London	265 ppm	265 ppm	Hard
DA18	Erith	262 ppm	262 ppm	Hard
EC2V	London	262 ppm	262 ppm	Hard
RM20	Grays	262 ppm	262 ppm	Hard
DA17	Belvedere	261 ppm	261 ppm	Hard
DA16	Welling	260 ppm	260 ppm	Hard
DA15	Sidcup	259 ppm	259 ppm	Hard
DA14	Sidcup	258 ppm	258 ppm	Hard
EC2R	London	258 ppm	258 ppm	Hard
DA13	Gravesend	257 ppm	257 ppm	Hard
DA12	Gravesend	256 ppm	256 ppm	Hard
DA11	Gravesend	255 ppm	255 ppm	Hard
WD25	Watford	255 ppm	255 ppm	Hard
DA10	Swanscombe	254 ppm	254 ppm	Hard
EC2N	London	254 ppm	254 ppm	Hard
WD24	Watford	254 ppm	254 ppm	Hard
EC2M	London	253 ppm	253 ppm	Hard
WD23	Bushey	253 ppm	253 ppm	Hard
E9	London	251 ppm	251 ppm	Hard
E8	London	250 ppm	250 ppm	Hard
EN11	Hoddesdon	247 ppm	247 ppm	Hard
EN10	Broxbourne	246 ppm	246 ppm	Hard
SM7	Banstead	242 ppm	242 ppm	Hard
SM6	Wallington	241 ppm	241 ppm	Hard
SM5	Carshalton	240 ppm	240 ppm	Hard
SM4	Morden	239 ppm	239 ppm	Hard
SM3	Sutton	238 ppm	238 ppm	Hard
SM2	Sutton	237 ppm	237 ppm	Hard
SM1	Sutton	236 ppm	236 ppm	Hard
WD7	Radlett	228 ppm	228 ppm	Hard
WD6	Borehamwood	227 ppm	227 ppm	Hard
WD19	Watford	226 ppm	226 ppm	Hard
WD5	Abbots Langley	226 ppm	226 ppm	Hard
WD18	Watford	225 ppm	225 ppm	Hard
WD4	Kings Langley	225 ppm	225 ppm	Hard
WD17	Watford	224 ppm	224 ppm	Hard
WD3	Rickmansworth	224 ppm	224 ppm	Hard

Hard Water Guides

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