DL12 tap water: what's in it?
Northumbrian, Essex and Suffolk Water group (figures include Northumbrian Water): at least 36 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Some published DWI figures don't reconcile or identify a company, so we've left them out; the true number may be higher. England overall: 99.97% of tests met standards.
DL12 tap water quality report · 2026
Hardness
Not covered
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
Details
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
Hosepipe ban
No hosepipe ban
Checked 11 October 2026 at 02:34
Details
Checked 11 October 2026 at 02:34
Storm overflows
29 overflows within 10 km of DL12 centre
519 spills in 2025
Details
519 spills in 2025
Lead pipes
68% built before 1973
Estimate, not a test. Homes in the parts of DL12 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 66–68%. England and Wales: 61% (2026).
Details
Estimate, not a test. Homes in the parts of DL12 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 66–68%. England and Wales: 61% (2026).
Who supplies water in DL12
Part of Northumbrian, Essex and Suffolk Water
Supplies 723 of 726 postcodes (100%)
Sewerage: Usually Northumbrian Water — they provide water and sewerage across most of their area. Your water bill confirms yours.
Also supplied here: Yorkshire Water (2 of 726 postcodes (0%)); United Utilities (1 of 726 postcodes (0%))
Drinking-water test record
Northumbrian Water: 723 of 726 postcodes
Northumbrian Water
Northumbrian, Essex and Suffolk Water group, includes Northumbrian Water
- Regulator
- DWI
- Report year
- 2025
- Failed tests
- Not shown
- Tests
- 266,202
The regulator's published total and its company rows disagree, so we don't show a count.
| Parameter | Failed tests |
|---|---|
| Aluminium | Failed tests: 4 |
| E. coli (confirmed) | Failed tests: 3 |
| Enterococci (confirmed) | Failed tests: 1 |
| Iron | Failed tests: 9 |
| Lead | Failed tests: 5 |
| Manganese | Failed tests: 3 |
| Nickel | Failed tests: 2 |
| Nitrite – consumers taps | Failed tests: 1 |
| Sodium | Failed tests: 1 |
| Total coliforms (confirmed) | Failed tests: 7 |
Source: DWI england 2025, Annex B — dated 6 July 2026, read 13 October 2026
Source: DWI england 2025, Annex A — dated 6 July 2026, read 13 October 2026
England: 99.97% of tests met standards in 2025 (DWI).
Source: DWI england 2025, national compliance — dated 6 July 2026, read 13 October 2026
Yorkshire Water: 2 of 726 postcodes
Yorkshire Water
Yorkshire Water, company-wide
- Regulator
- DWI
- Report year
- 2025
- Failed tests
- Not shown
- Tests
- 388,919
The regulator's published total and its company rows disagree, so we don't show a count.
| Parameter | Failed tests |
|---|---|
| E. coli (confirmed) | Failed tests: 4 |
| Enterococci (confirmed) | Failed tests: 2 |
| Iron | Failed tests: 20 |
| Lead | Failed tests: 6 |
| Nickel | Failed tests: 7 |
| Total coliforms (confirmed) | Failed tests: 30 |
Source: DWI england 2025, Annex B — dated 6 July 2026, read 13 October 2026
Source: DWI england 2025, Annex A — dated 6 July 2026, read 13 October 2026
England: 99.97% of tests met standards in 2025 (DWI).
Source: DWI england 2025, national compliance — dated 6 July 2026, read 13 October 2026
United Utilities: 1 of 726 postcodes
United Utilities
United Utilities, company-wide
- Regulator
- DWI
- Report year
- 2025
- Failed tests
- Not shown
- Tests
- 385,673
The regulator's published total and its company rows disagree, so we don't show a count.
| Parameter | Failed tests |
|---|---|
| Aluminium | Failed tests: 5 |
| E. coli (confirmed) | Failed tests: 4 |
| Iron | Failed tests: 18 |
| Lead | Failed tests: 7 |
| Manganese | Failed tests: 7 |
| Nickel | Failed tests: 3 |
| Total coliforms (confirmed) | Failed tests: 13 |
Source: DWI england 2025, Annex B — dated 6 July 2026, read 13 October 2026
Source: DWI england 2025, Annex A — dated 6 July 2026, read 13 October 2026
England: 99.97% of tests met standards in 2025 (DWI).
Source: DWI england 2025, national compliance — dated 6 July 2026, read 13 October 2026
How hard is the water in DL12?
Across DL12's supply zones, hardness ranges from 76 mg/l (soft) to 77 mg/l (soft). Those 3 zones cover 43% of its postcodes.
3 identified supply zones in DL12
Barnard Castle Zone · Northumbrian Water (218 of 726 postcodes)
76 mg/l · 5.3 °Clark · 4.3 °dH · 7.6 °fH
Zone average.
Barnard Castle Zone (supply zone) · January 2025 to December 2025
Source: Northumbrian Water — dated January 2025 to December 2025, read 28 September 2026
Lartington WTW to Longnewton Zone · Northumbrian Water (88 of 726 postcodes)
77 mg/l · 5.4 °Clark · 4.3 °dH · 7.7 °fH
Zone average.
Lartington WTW to Longnewton Zone (supply zone) · January 2025 to December 2025
Source: Northumbrian Water — dated January 2025 to December 2025, read 28 September 2026
Butterknowles & Staindrop Zone · Northumbrian Water (3 of 726 postcodes)
77 mg/l · 5.4 °Clark · 4.3 °dH · 7.7 °fH
Zone average.
Butterknowles & Staindrop Zone (supply zone) · January 2025 to December 2025
Source: Northumbrian Water — dated January 2025 to December 2025, read 28 September 2026
417 postcodes without an identified supply zone
Northumbrian Water (414 of 726 postcodes)
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
Yorkshire Water (2 of 726 postcodes)
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
United Utilities (1 of 726 postcodes)
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
Storm overflows nearby
29 overflows within 10 km of DL12 centre · 519 spills in 2025
DL12 (district) · 2025
Source: Environment Agency EDM annual return 2025 — dated 20 August 2026, read 13 October 2026
Overflows here are run by Northumbrian Water.
28 of these were monitored for only part of 2025.
Nearest 5 shown
THE HAGG CSO
Into TRIB OF RIVER BALDER · 0.2 km from the centre of DL12
25 spills · 32.7 hours · Monitored 86.9% of 2025
BALDER COTTAGE CSO
Into RIVER BALDER · 0.4 km from the centre of DL12
0 spills · 0 hours · Monitored 75.1% of 2025
WINDMILL COTTAGE CSO THE MILL TE066
Into UNNAMED TRIB OF LANCE BECK · 0.4 km from the centre of DL12
7 spills · 3.9 hours · Monitored 99.8% of 2025
COTHERSTONE STW
Into RIVER BALDER · 0.5 km from the centre of DL12
161 spills · 2,196.5 hours · Monitored 99.8% of 2025
ROMALDKIRK SEWAGE DISPOSAL WORKS
Into RIVER TEES · 3.1 km from the centre of DL12
11 spills · 6.7 hours · Monitored 99.3% of 2025
Annual 2025 figures from monitored overflows. Not live, and not a bathing-water or tap-water verdict.
- 57 England outfalls in the 2025 return had no usable location and aren't counted.
- Northern Ireland isn't covered: No licensed annual per-outfall source in the approved source list; BT postcode coordinates require an LPS licence.
Older homes and lead pipes
68% built before 1973
68% of homes here were built before 1973 — estimate, not a test.
Homes in the parts of DL12 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 66–68%. England and Wales: 61% (2026).
Older homes are more likely to have lead pipes. Only a test tells you whether yours does.
DL12 (district) · 2026
Source: Valuation Office Agency, Council Tax: stock of properties — dated 31 March 2026, read 24 September 2026
Fluoride
We cannot confirm whether this area is part of a water fluoridation scheme. Ask your water supplier using your postcode.
Around one in ten people in England receive drinking water supplied by a fluoridation scheme.
England · 2026 health monitoring report
Source: UKHSA and DHSC — dated 30 March 2026, read 13 October 2026
Hosepipe bans
What you can do
General picks — we don't hold your hardness
As an Amazon Associate we earn from qualifying purchases. Links go to amazon.com; Amazon's Earn Globally service can localise them to amazon.co.uk. Check the model and UK delivery before buying.
Water filter jugs
LifeStraw
LSH7GLSPK21
Performance certification:
Certified by WQA to NSF/ANSI 42 for Aesthetic Chlorine and Taste and Odor; Certified by WQA to NSF/ANSI 53 for Lead and Mercury; Certified by WQA to NSF/ANSI 401 for Microplastics (a US/international standard; it is not UK approval)
View Detailsreduces chlorine taste and odour in drinking water.
A UK retailer lists this model. Amazon UK stock and delivery are unverified; this Amazon link may not ship to the UK. Check the exact model and UK delivery before you pay.
UK availability evidence checked 14 October 2026.
Shower filters
Weddell Water
WD-100BL
Performance certification:
Certified by NSF to NSF/ANSI 177 for Free Available Chlorine Reduction (a US/international standard; it is not UK approval)
View Detailsreduces chlorine in shower water; does not soften water.
A UK retailer lists this model. Amazon UK stock and delivery are unverified; this Amazon link may not ship to the UK. Check the exact model and UK delivery before you pay.
Check it fits your shower fitting before buying; a US fitting may need an adaptor.
UK availability evidence checked 14 October 2026.
We haven't verified a lead test kit for UK buyers yet.
What a pick has to pass:
- A lead result reported by a laboratory accredited for that test (UKAS, ISO/IEC 17025), named on the kit's listing
- UK availability evidenced by Amazon UK, the manufacturer or a UK retailer, checked in the last 90 days
Start with your water company: if you think you have lead pipes, you can ask it to test the water at your kitchen tap. Which water test you need
Common water problems
How much does a water softener cost in the UK?
Water softener cost UK 2026: price by home size
Why is my tap water cloudy or white?
Why is my tap water cloudy or white? (UK)
Brown tap water: causes and what to do (UK)
Why does my tap water taste metallic?
Tap water tastes metallic? Causes and fixes (UK)
Questions about tap water in DL12
- Is the water in DL12 hard or soft?
- Northumbrian Water: We do not have a verified hardness figure for this area. Ask your water company for its water quality report. Northumbrian Water: soft, 76 mg/l, 5.3 °Clark, 4.3 °dH, 7.6 °fH (Barnard Castle Zone (supply zone), January 2025 to December 2025). Zone average. Northumbrian Water: soft, 77 mg/l, 5.4 °Clark, 4.3 °dH, 7.7 °fH (Lartington WTW to Longnewton Zone (supply zone), January 2025 to December 2025). Zone average. Northumbrian Water: soft, 77 mg/l, 5.4 °Clark, 4.3 °dH, 7.7 °fH (Butterknowles & Staindrop Zone (supply zone), January 2025 to December 2025). Zone average. Yorkshire Water: We do not have a verified hardness figure for this area. Ask your water company for its water quality report. United Utilities: We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
- What does the drinking water regulator's record show for DL12?
- Northumbrian, Essex and Suffolk Water group (figures include Northumbrian Water): at least 36 tests failed UK drinking-water standards in 2025 (DWI, company-wide). Some published DWI figures don't reconcile or identify a company, so we've left them out; the true number may be higher. England overall: 99.97% of tests met standards.
- Could homes in DL12 have lead pipes?
- 68% of homes here were built before 1973 — estimate, not a test. Homes in the parts of DL12 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 66–68%. England and Wales: 61% (2026). Older homes are more likely to have lead pipes. Only a test tells you whether yours does.
- Is the water in DL12 fluoridated?
- We cannot confirm whether this area is part of a water fluoridation scheme. Ask your water supplier using your postcode. Around one in ten people in England receive drinking water supplied by a fluoridation scheme.
Sources and method
- Water Company Boundaries (UC2) ↗ · 19 September 2026 · read 20 September 2026
- Northumbrian Water contact page ↗ · 13 October 2026 · read 13 October 2026
- DWI england 2025, Annex B ↗ · 2025 · read 13 October 2026
- DWI england 2025, national compliance ↗ · 2025 · read 13 October 2026
- Northumbrian Water ↗ · January 2025 to December 2025 · read 28 September 2026
- Northumbrian Water ↗ · January 2025 to December 2025 · read 28 September 2026
- Northumbrian Water ↗ · January 2025 to December 2025 · read 28 September 2026
- Environment Agency EDM annual return 2025 ↗ · 2025 · read 13 October 2026
- Valuation Office Agency, Council Tax: stock of properties ↗ · 2026 · read 24 September 2026
- UKHSA and DHSC ↗ · 2026 health monitoring report · read 13 October 2026
- Environment Agency ↗ · 11 October 2026 · read 11 October 2026
Northumbrian Water contact page, Northumbrian Water, Northumbrian Water, Northumbrian Water: Database right, used under the publisher's terms.
Water company boundaries © Water UK, licensed under CC BY 4.0Contains public sector information licensed under the Open Government Licence v3.0All content is available under the Open Government Licence v3.0, except where otherwise stated © Crown copyright
Data generation uk-2026-10-16-derive6