Hardest Water Areas in the UK

The 50 postcode districts with the highest water hardness levels, ranked by PPM.

#	Postcode	Town	Water Company	Hardness	PPM
1	CM19	Harlow	Anglian Water	394 ppm	394 ppm
2	CM18	Harlow	Anglian Water	393 ppm	393 ppm
3	IP33	Bury St Edmunds	Anglian Water	393 ppm	393 ppm
4	CM17	Harlow	Anglian Water	392 ppm	392 ppm
5	IP32	Bury St Edmunds	Anglian Water	392 ppm	392 ppm
6	NR19	Dereham	Anglian Water	392 ppm	392 ppm
7	CM16	Epping	Anglian Water	391 ppm	391 ppm
8	IP31	Bury St Edmunds	Anglian Water	391 ppm	391 ppm
9	NR18	Wymondham	Anglian Water	391 ppm	391 ppm
10	CM15	Brentwood	Anglian Water	390 ppm	390 ppm
11	IP30	Bury St Edmunds	Anglian Water	390 ppm	390 ppm
12	NR17	Attleborough	Anglian Water	390 ppm	390 ppm
13	CM14	Brentwood	Anglian Water	389 ppm	389 ppm
14	NR16	Norwich	Anglian Water	389 ppm	389 ppm
15	CM13	Brentwood	Anglian Water	388 ppm	388 ppm
16	NR15	Norwich	Anglian Water	388 ppm	388 ppm
17	CM12	Billericay	Anglian Water	387 ppm	387 ppm
18	NR14	Norwich	Anglian Water	387 ppm	387 ppm
19	CM11	Billericay	Anglian Water	386 ppm	386 ppm
20	NR13	Norwich	Anglian Water	386 ppm	386 ppm
21	LN9	Horncastle	Anglian Water	385 ppm	385 ppm
22	NR12	Norwich	Anglian Water	385 ppm	385 ppm
23	LN8	Market Rasen	Anglian Water	384 ppm	384 ppm
24	NR11	Norwich	Anglian Water	384 ppm	384 ppm
25	LN7	Market Rasen	Anglian Water	383 ppm	383 ppm
26	NR10	Norwich	Anglian Water	383 ppm	383 ppm
27	LN6	Lincoln	Anglian Water	382 ppm	382 ppm
28	LN5	Lincoln	Anglian Water	381 ppm	381 ppm
29	LN4	Lincoln	Anglian Water	380 ppm	380 ppm
30	LN3	Lincoln	Anglian Water	379 ppm	379 ppm
31	LN2	Lincoln	Anglian Water	378 ppm	378 ppm
32	SG9	Buntingford	Anglian Water	378 ppm	378 ppm
33	LN1	Lincoln	Anglian Water	377 ppm	377 ppm
34	SG8	Royston	Anglian Water	377 ppm	377 ppm
35	SG7	Baldock	Anglian Water	376 ppm	376 ppm
36	SG6	Letchworth Garden City	Anglian Water	375 ppm	375 ppm
37	SG5	Hitchin	Anglian Water	374 ppm	374 ppm
38	CB25	Cambridge	Anglian Water	373 ppm	373 ppm
39	SG4	Hitchin	Anglian Water	373 ppm	373 ppm
40	CB24	Cambridge	Anglian Water	372 ppm	372 ppm
41	SG3	Knebworth	Anglian Water	372 ppm	372 ppm
42	CB23	Cambridge	Anglian Water	371 ppm	371 ppm
43	SG2	Stevenage	Anglian Water	371 ppm	371 ppm
44	CB22	Cambridge	Anglian Water	370 ppm	370 ppm
45	SG1	Stevenage	Anglian Water	370 ppm	370 ppm
46	CB21	Cambridge	Anglian Water	369 ppm	369 ppm
47	PE9	Stamford	Anglian Water	367 ppm	367 ppm
48	CM9	Maldon	Anglian Water	366 ppm	366 ppm
49	IP29	Bury St Edmunds	Anglian Water	366 ppm	366 ppm
50	PE8	Peterborough	Anglian Water	366 ppm	366 ppm

About UK Water Hardness

Water hardness in the UK varies dramatically by region. The hardest water is found in areas served by Anglian Water and Thames Water, where chalk and limestone aquifers dissolve calcium carbonate into the water supply. The South East and East of England consistently record the highest levels, often exceeding 300 ppm.

Learn more about what water hardness means or explore solutions for hard water.