Is Cardiff tap water safe to drink?
Dŵr Cymru Welsh Water: at least 59 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. Wales overall: 99.97% of tests met standards.
Cardiff 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
Not available
We can't confirm the hosepipe-ban status for Dŵr Cymru Welsh Water from the information we hold.
Details
We can't confirm the hosepipe-ban status for Dŵr Cymru Welsh Water from the information we hold.
Storm overflows
59 overflows within 10 km of Cardiff centre
1,657 spills in 2025
Details
1,657 spills in 2025
Lead pipes
59% built before 1973
Estimate, not a test. Homes in the parts of Cardiff 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: 57–59%. England and Wales: 61% (2026).
Details
Estimate, not a test. Homes in the parts of Cardiff 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: 57–59%. England and Wales: 61% (2026).
Who supplies water in Cardiff
Supplies 7,654 of 7,654 postcodes (100%)
Dŵr Cymru Welsh Water's phone number isn't in our records; their contact page lists it.
Sewerage: Usually Dŵr Cymru Welsh Water — they provide water and sewerage across most of their area. Your water bill confirms yours.
Drinking-water test record
Dŵr Cymru Welsh Water: 7,654 of 7,654 postcodes
Dŵr Cymru Welsh Water
Dŵr Cymru Welsh Water, company-wide
- Regulator
- DWI
- Report year
- 2025
- Failed tests
- Not shown
- Tests
- Not given in the report
The regulator's published total and its company rows disagree, so we don't show a count.
| Parameter | Failed tests |
|---|---|
| Coliform bacteria (indicator) | Failed tests: 24 |
| E. coli (confirmed) | Failed tests: 2 |
| Lead | Failed tests: 2 |
| Manganese | Failed tests: 1 |
| Odour | Failed tests: 5 |
| Taste (quantitative) | Failed tests: 5 |
| Total coliforms (confirmed) | Failed tests: 20 |
Source: DWI wales 2025, Annex B — dated 14 July 2026, read 13 October 2026
Source: DWI wales 2025, Annex A — dated 14 July 2026, read 13 October 2026
Wales: 99.97% of tests met standards in 2025 (DWI).
Source: DWI wales 2025, national compliance — dated 9 July 2026, read 13 October 2026
How hard is the water in Cardiff?
Dŵr Cymru Welsh Water (7,654 of 7,654 postcodes)
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
Storm overflows nearby
59 overflows within 10 km of Cardiff centre · 1,657 spills in 2025
near Cardiff centre
Cardiff (7,654 of its postcodes) · 2025
Source: The Rivers Trust (EA/NRW EDM 2025) — dated 8 September 2026, read 13 October 2026
Overflows here are run by Dwr Cymru Welsh Water.
59 of these were monitored for only part of 2025.
Nearest 5 shown
HEATHWOOD ROAD CSO, HEATHWOOD JUNCTION
Receiving water not named in the return · 1.2 km from the centre of Cardiff
27 spills · 27.3 hours · Monitored 92.8% of 2025
ABERPORTH RD CSO
Receiving water not named in the return · 1.5 km from the centre of Cardiff
9 spills · 17 hours · Monitored 91.9% of 2025
Kimberly Road CSO
Receiving water not named in the return · 1.7 km from the centre of Cardiff
0 spills · 0 hours · Monitored 99.9% of 2025
Park Street PS
Receiving water not named in the return · 2.6 km from the centre of Cardiff
6 spills · 4.8 hours · Monitored 99.9% of 2025
Cardiff Wood St/Havelock St Jn CSO
Receiving water not named in the return · 2.6 km from the centre of Cardiff
13 spills · 13.5 hours · Monitored 99.6% 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
59% built before 1973
59% of homes here were built before 1973 — estimate, not a test.
District housing counts allocated by the town’s share of member postcodes. Homes in the parts of Cardiff 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: 57–59%. England and Wales: 61% (2026).
Older homes are more likely to have lead pipes. Only a test tells you whether yours does.
Cardiff (7,654 of its postcodes) · 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 Cardiff
- Is the water in Cardiff hard or soft?
- Dŵr Cymru Welsh Water: 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 Cardiff?
- Dŵr Cymru Welsh Water: at least 59 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. Wales overall: 99.97% of tests met standards.
- Could homes in Cardiff have lead pipes?
- 59% of homes here were built before 1973 — estimate, not a test. Homes in the parts of Cardiff 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: 57–59%. 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 Cardiff 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
- DWI wales 2025, Annex B ↗ · 2025 · read 13 October 2026
- DWI wales 2025, national compliance ↗ · 2025 · read 13 October 2026
- The Rivers Trust (EA/NRW EDM 2025) ↗ · 2025 · read 13 October 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
Water company boundaries © Water UK, licensed under CC BY 4.0Contains public sector information licensed under the Open Government Licence v3.0
Data generation uk-2026-10-16-derive6